Complement activation initiated by the interaction of microbial ANTIGENS with COMPLEMENT C3B. When COMPLEMENT FACTOR B binds to the membrane-bound C3b, COMPLEMENT FACTOR D cleaves it to form alternative C3 CONVERTASE (C3BBB) which, stabilized by COMPLEMENT FACTOR P, is able to cleave multiple COMPLEMENT C3 to form alternative C5 CONVERTASE (C3BBB3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
Complement activation initiated by the binding of COMPLEMENT C1 to ANTIGEN-ANTIBODY COMPLEXES at the COMPLEMENT C1Q subunit. This leads to the sequential activation of COMPLEMENT C1R and COMPLEMENT C1S subunits. Activated C1s cleaves COMPLEMENT C4 and COMPLEMENT C2 forming the membrane-bound classical C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.
A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.
Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).
A glycoprotein that is important in the activation of CLASSICAL COMPLEMENT PATHWAY. C4 is cleaved by the activated COMPLEMENT C1S into COMPLEMENT C4A and COMPLEMENT C4B.
A glycine-rich, heat-labile serum glycoprotein that contains a component of the C3 CONVERTASE ALTERNATE PATHWAY (C3bBb). Bb, a serine protease, is generated when factor B is cleaved by COMPLEMENT FACTOR D into Ba and Bb.
A subcomponent of complement C1, composed of six copies of three polypeptide chains (A, B, and C), each encoded by a separate gene (C1QA; C1QB; C1QC). This complex is arranged in nine subunits (six disulfide-linked dimers of A and B, and three disulfide-linked homodimers of C). C1q has binding sites for antibodies (the heavy chain of IMMUNOGLOBULIN G or IMMUNOGLOBULIN M). The interaction of C1q and immunoglobulin activates the two proenzymes COMPLEMENT C1R and COMPLEMENT C1S, thus initiating the cascade of COMPLEMENT ACTIVATION via the CLASSICAL COMPLEMENT PATHWAY.
Complement activation triggered by the interaction of microbial POLYSACCHARIDES with serum MANNOSE-BINDING LECTIN resulting in the activation of MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. As in the classical pathway, MASPs cleave COMPLEMENT C4 and COMPLEMENT C2 to form C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.
A component of the CLASSICAL COMPLEMENT PATHWAY. C2 is cleaved by activated COMPLEMENT C1S into COMPLEMENT C2B and COMPLEMENT C2A. C2a, the COOH-terminal fragment containing a SERINE PROTEASE, combines with COMPLEMENT C4B to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).
The larger fragment generated from the cleavage of COMPLEMENT C3 by C3 CONVERTASE. It is a constituent of the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb), and COMPLEMENT C5 CONVERTASES in both the classical (C4b2a3b) and the alternative (C3bBb3b) pathway. C3b participates in IMMUNE ADHERENCE REACTION and enhances PHAGOCYTOSIS. It can be inactivated (iC3b) or cleaved by various proteases to yield fragments such as COMPLEMENT C3C; COMPLEMENT C3D; C3e; C3f; and C3g.
The first complement component to act in the activation of CLASSICAL COMPLEMENT PATHWAY. It is a calcium-dependent trimolecular complex made up of three subcomponents: COMPLEMENT C1Q; COMPLEMENT C1R; and COMPLEMENT C1S at 1:2:2 ratios. When the intact C1 binds to at least two antibodies (involving C1q), C1r and C1s are sequentially activated, leading to subsequent steps in the cascade of COMPLEMENT ACTIVATION.
C5 plays a central role in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C5 is cleaved by C5 CONVERTASE into COMPLEMENT C5A and COMPLEMENT C5B. The smaller fragment C5a is an ANAPHYLATOXIN and mediator of inflammatory process. The major fragment C5b binds to the membrane initiating the spontaneous assembly of the late complement components, C5-C9, into the MEMBRANE ATTACK COMPLEX.
Serum proteins that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host. The complement system is tightly regulated by inactivators that accelerate the decay of intermediates and certain cell surface receptors.
A serum protein which is important in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. This enzyme cleaves the COMPLEMENT C3B-bound COMPLEMENT FACTOR B to form C3bBb which is ALTERNATIVE PATHWAY C3 CONVERTASE.
Serine proteases that cleave COMPLEMENT C3 into COMPLEMENT C3A and COMPLEMENT C3B, or cleave COMPLEMENT C5 into COMPLEMENT C5A and COMPLEMENT C5B. These include the different forms of C3/C5 convertases in the classical and the alternative pathways of COMPLEMENT ACTIVATION. Both cleavages take place at the C-terminal of an ARGININE residue.
A 53-kDa protein that is a positive regulator of the alternate pathway of complement activation (COMPLEMENT ACTIVATION PATHWAY, ALTERNATIVE). It stabilizes the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb) and protects it from rapid inactivation, thus facilitating the cascade of COMPLEMENT ACTIVATION and the formation of MEMBRANE ATTACK COMPLEX. Individuals with mutation in the PFC gene exhibit properdin deficiency and have a high susceptibility to infections.
An important soluble regulator of the alternative pathway of complement activation (COMPLEMENT ACTIVATION PATHWAY, ALTERNATIVE). It is a 139-kDa glycoprotein expressed by the liver and secreted into the blood. It binds to COMPLEMENT C3B and makes iC3b (inactivated complement 3b) susceptible to cleavage by COMPLEMENT FACTOR I. Complement factor H also inhibits the association of C3b with COMPLEMENT FACTOR B to form the C3bB proenzyme, and promotes the dissociation of Bb from the C3bBb complex (COMPLEMENT C3 CONVERTASE, ALTERNATIVE PATHWAY).
Molecules on the surface of some B-lymphocytes and macrophages, that recognize and combine with the C3b, C3d, C1q, and C4b components of complement.
A product of COMPLEMENT ACTIVATION cascade, regardless of the pathways, that forms transmembrane channels causing disruption of the target CELL MEMBRANE and cell lysis. It is formed by the sequential assembly of terminal complement components (COMPLEMENT C5B; COMPLEMENT C6; COMPLEMENT C7; COMPLEMENT C8; and COMPLEMENT C9) into the target membrane. The resultant C5b-8-poly-C9 is the "membrane attack complex" or MAC.
A 105-kDa serum glycoprotein with significant homology to the other late complement components, C7-C9. It is a polypeptide chain cross-linked by 32 disulfide bonds. C6 is the next complement component to bind to the membrane-bound COMPLEMENT C5B in the assembly of MEMBRANE ATTACK COMPLEX. It is encoded by gene C6.
The large fragment formed when COMPLEMENT C4 is cleaved by COMPLEMENT C1S. The membrane-bound C4b binds COMPLEMENT C2A, a SERINE PROTEASE, to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).
Endogenous proteins that inhibit or inactivate COMPLEMENT C3B. They include COMPLEMENT FACTOR H and COMPLEMENT FACTOR I (C3b/C4b inactivator). They cleave or promote the cleavage of C3b into inactive fragments, and thus are important in the down-regulation of COMPLEMENT ACTIVATION and its cytolytic sequence.
Enzymes that activate one or more COMPLEMENT PROTEINS in the complement system leading to the formation of the COMPLEMENT MEMBRANE ATTACK COMPLEX, an important response in host defense. They are enzymes in the various COMPLEMENT ACTIVATION pathways.
A screening assay for circulating COMPLEMENT PROTEINS. Diluted SERUM samples are added to antibody-coated ERYTHROCYTES and the percentage of cell lysis is measured. The values are expressed by the so called CH50, in HEMOLYTIC COMPLEMENT units per milliliter, which is the dilution of serum required to lyse 50 percent of the erythrocytes in the assay.
A 63-kDa serum glycoprotein encoded by gene C9. Monomeric C9 (mC9) binds the C5b-8 complex to form C5b-9 which catalyzes the polymerization of C9 forming C5b-p9 (MEMBRANE ATTACK COMPLEX) and transmembrane channels leading to lysis of the target cell. Patients with C9 deficiency suffer from recurrent bacterial infections.
Compounds that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host.
A process whereby multiple RNA transcripts are generated from a single gene. Alternative splicing involves the splicing together of other possible sets of EXONS during the processing of some, but not all, transcripts of the gene. Thus a particular exon may be connected to any one of several alternative exons to form a mature RNA. The alternative forms of mature MESSENGER RNA produce PROTEIN ISOFORMS in which one part of the isoforms is common while the other parts are different.
Serum serine proteases which participate in COMPLEMENT ACTIVATION. They are activated when complexed with the MANNOSE-BINDING LECTIN, therefore also known as Mannose-binding protein-Associated Serine Proteases (MASPs). They cleave COMPLEMENT C4 and COMPLEMENT C2 to form C4b2a, the CLASSICAL PATHWAY C3 CONVERTASE.
The smaller fragment generated from the cleavage of complement C3 by C3 CONVERTASE. C3a, a 77-amino acid peptide, is a mediator of local inflammatory process. It induces smooth MUSCLE CONTRACTION, and HISTAMINE RELEASE from MAST CELLS and LEUKOCYTES. C3a is considered an anaphylatoxin along with COMPLEMENT C4A; COMPLEMENT C5A; and COMPLEMENT C5A, DES-ARGININE.
A specific mannose-binding member of the collectin family of lectins. It binds to carbohydrate groups on invading pathogens and plays a key role in the MANNOSE-BINDING LECTIN COMPLEMENT PATHWAY.
A 206-amino-acid fragment in the alpha chain (672-1663) of C3b. It is generated when C3b is inactivated (iC3b) and its alpha chain is cleaved by COMPLEMENT FACTOR I into C3c (749-954), and C3dg (955-1303) in the presence COMPLEMENT FACTOR H.
Serum proteins that inhibit, antagonize, or inactivate COMPLEMENT C1 or its subunits.
A 302-amino-acid fragment in the alpha chain (672-1663) of C3b. It is generated when C3b is inactivated (iC3b) and its alpha chain is cleaved by COMPLEMENT FACTOR I into C3c, and C3dg (955-1303) in the presence COMPLEMENT FACTOR H. Serum proteases further degrade C3dg into C3d (1002-1303) and C3g (955-1001).
The minor fragment formed when C5 convertase cleaves C5 into C5a and COMPLEMENT C5B. C5a is a 74-amino-acid glycopeptide with a carboxy-terminal ARGININE that is crucial for its spasmogenic activity. Of all the complement-derived anaphylatoxins, C5a is the most potent in mediating immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE), smooth MUSCLE CONTRACTION; HISTAMINE RELEASE; and migration of LEUKOCYTES to site of INFLAMMATION.
The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.
Proteins that bind to particles and cells to increase susceptibility to PHAGOCYTOSIS, especially ANTIBODIES bound to EPITOPES that attach to FC RECEPTORS. COMPLEMENT C3B may also participate.
The natural bactericidal property of BLOOD due to normally occurring antibacterial substances such as beta lysin, leukin, etc. This activity needs to be distinguished from the bactericidal activity contained in a patient's serum as a result of antimicrobial therapy, which is measured by a SERUM BACTERICIDAL TEST.
Molecular sites on or in some B-lymphocytes and macrophages that recognize and combine with COMPLEMENT C3B. The primary structure of these receptors reveal that they contain transmembrane and cytoplasmic domains, with their extracellular portion composed entirely of thirty short consensus repeats each having 60 to 70 amino acids.
Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.
A 77-kDa subcomponent of complement C1, encoded by gene C1S, is a SERINE PROTEASE existing as a proenzyme (homodimer) in the intact complement C1 complex. Upon the binding of COMPLEMENT C1Q to antibodies, the activated COMPLEMENT C1R cleaves C1s into two chains, A (heavy) and B (light, the serine protease), linked by disulfide bonds yielding the active C1s. The activated C1s, in turn, cleaves COMPLEMENT C2 and COMPLEMENT C4 to form C4b2a (CLASSICAL C3 CONVERTASE).
A plasma serine proteinase that cleaves the alpha-chains of C3b and C4b in the presence of the cofactors COMPLEMENT FACTOR H and C4-binding protein, respectively. It is a 66-kDa glycoprotein that converts C3b to inactivated C3b (iC3b) followed by the release of two fragments, C3c (150-kDa) and C3dg (41-kDa). It was formerly called KAF, C3bINF, or enzyme 3b inactivator.
A serum protein that regulates the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It binds as a cofactor to COMPLEMENT FACTOR I which then hydrolyzes the COMPLEMENT C4B in the CLASSICAL PATHWAY C3 CONVERTASE (C4bC2a).
Zymosan is a polysaccharide derived from the cell walls of Saccharomyces cerevisiae, commonly used in research as an immunostimulant to induce inflammation and study phagocytosis, complement activation, and oxidative burst in neutrophils and macrophages.
A serine protease that is the complex of COMPLEMENT C3B and COMPLEMENT FACTOR BB. It cleaves multiple COMPLEMENT C3 into COMPLEMENT C3A (anaphylatoxin) and COMPLEMENT C3B in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY.
The larger fragment generated from the cleavage of C5 by C5 CONVERTASE that yields COMPLEMENT C5A and C5b (beta chain + alpha' chain, the residual alpha chain, bound by disulfide bond). C5b remains bound to the membrane and initiates the spontaneous assembly of the late complement components to form C5b-8-poly-C9, the MEMBRANE ATTACK COMPLEX.
The smaller fragment formed when complement C4 is cleaved by COMPLEMENT C1S. It is an anaphylatoxin that causes symptoms of immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE) but its activity is weaker than that of COMPLEMENT C3A or COMPLEMENT C5A.
GPI-linked membrane proteins broadly distributed among hematopoietic and non-hematopoietic cells. CD55 prevents the assembly of C3 CONVERTASE or accelerates the disassembly of preformed convertase, thus blocking the formation of the membrane attack complex.
The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).
Venoms from snakes of the genus Naja (family Elapidae). They contain many specific proteins that have cytotoxic, hemolytic, neurotoxic, and other properties. Like other elapid venoms, they are rich in enzymes. They include cobramines and cobralysins.
The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.
The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.
A class of C-type lectins that target the carbohydrate structures found on invading pathogens. Binding of collectins to microorganisms results in their agglutination and enhanced clearance. Collectins form trimers that may assemble into larger oligomers. Each collectin polypeptide chain consists of four regions: a relatively short N-terminal region, a collagen-like region, an alpha-helical coiled-coil region, and carbohydrate-binding region.
A 80-kDa subcomponent of complement C1, existing as a SERINE PROTEASE proenzyme in the intact complement C1 complex. When COMPLEMENT C1Q is bound to antibodies, the changed tertiary structure causes autolytic activation of complement C1r which is cleaved into two chains, A (heavy) and B (light, the serine protease), connected by disulfide bonds. The activated C1r serine protease, in turn, activates COMPLEMENT C1S proenzyme by cleaving the Arg426-Ile427 bond. No fragment is released when either C1r or C1s is cleaved.
A 93-kDa serum glycoprotein encoded by C7 gene. It is a polypeptide chain with 28 disulfide bridges. In the formation of MEMBRANE ATTACK COMPLEX; C7 is the next component to bind the C5b-6 complex forming a trimolecular complex C5b-7 which is lipophilic, resembles an integral membrane protein, and serves as an anchor for the late complement components, C8 and C9.
Proteins that share the common characteristic of binding to carbohydrates. Some ANTIBODIES and carbohydrate-metabolizing proteins (ENZYMES) also bind to carbohydrates, however they are not considered lectins. PLANT LECTINS are carbohydrate-binding proteins that have been primarily identified by their hemagglutinating activity (HEMAGGLUTININS). However, a variety of lectins occur in animal species where they serve diverse array of functions through specific carbohydrate recognition.
A 150-kDa serum glycoprotein composed of three subunits with each encoded by a different gene (C8A; C8B; and C8G). This heterotrimer contains a disulfide-linked C8alpha-C8gamma heterodimer and a noncovalently associated C8beta chain. C8 is the next component to bind the C5-7 complex forming C5b-8 that binds COMPLEMENT C9 and acts as a catalyst in the polymerization of C9.
Serum peptides derived from certain cleaved COMPLEMENT PROTEINS during COMPLEMENT ACTIVATION. They induce smooth MUSCLE CONTRACTION; mast cell HISTAMINE RELEASE; PLATELET AGGREGATION; and act as mediators of the local inflammatory process. The order of anaphylatoxin activity from the strongest to the weakest is C5a, C3a, C4a, and C5a des-arginine.
A ubiquitously expressed complement receptor that binds COMPLEMENT C3B and COMPLEMENT C4B and serves as a cofactor for their inactivation. CD46 also interacts with a wide variety of pathogens and mediates immune response.
Small glycoproteins found on both hematopoietic and non-hematopoietic cells. CD59 restricts the cytolytic activity of homologous complement by binding to C8 and C9 and blocking the assembly of the membrane attack complex. (From Barclay et al., The Leukocyte Antigen FactsBook, 1993, p234)
Molecular sites on or in B-lymphocytes, follicular dendritic cells, lymphoid cells, and epithelial cells that recognize and combine with COMPLEMENT C3D. Human complement receptor 2 (CR2) serves as a receptor for both C3dg and the gp350/220 glycoprotein of HERPESVIRUS 4, HUMAN, and binds the monoclonal antibody OKB7, which blocks binding of both ligands to the receptor.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally being called a macroglobulin.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.
Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.
Polysaccharides found in bacteria and in capsules thereof.
Limbless REPTILES of the suborder Serpentes.
Abnormal immunoglobulins, especially IGG or IGM, that precipitate spontaneously when SERUM is cooled below 37 degrees Celsius. It is characteristic of CRYOGLOBULINEMIA.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A species of gram-negative, anaerobic, rod-shaped bacteria originally classified within the BACTEROIDES genus. This bacterium has been isolated from the mouth, urine, feces, and infections of the mouth, soft tissue, respiratory tract, urogenital tract, and intestinal tract. It is pathogenic, but usually in association with other kinds of organisms.
Immunoglobulins produced in a response to BACTERIAL ANTIGENS.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
A gram-positive organism found in the upper respiratory tract, inflammatory exudates, and various body fluids of normal and/or diseased humans and, rarely, domestic animals.
Degenerative changes in the RETINA usually of older adults which results in a loss of vision in the center of the visual field (the MACULA LUTEA) because of damage to the retina. It occurs in dry and wet forms.
Inbred C57BL mice are a strain of laboratory mice that have been produced by many generations of brother-sister matings, resulting in a high degree of genetic uniformity and homozygosity, making them widely used for biomedical research, including studies on genetics, immunology, cancer, and neuroscience.
Physiological processes and properties of the BLOOD.
A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.
A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.
Multi-subunit proteins which function in IMMUNITY. They are produced by B LYMPHOCYTES from the IMMUNOGLOBULIN GENES. They are comprised of two heavy (IMMUNOGLOBULIN HEAVY CHAINS) and two light chains (IMMUNOGLOBULIN LIGHT CHAINS) with additional ancillary polypeptide chains depending on their isoforms. The variety of isoforms include monomeric or polymeric forms, and transmembrane forms (B-CELL ANTIGEN RECEPTORS) or secreted forms (ANTIBODIES). They are divided by the amino acid sequence of their heavy chains into five classes (IMMUNOGLOBULIN A; IMMUNOGLOBULIN D; IMMUNOGLOBULIN E; IMMUNOGLOBULIN G; IMMUNOGLOBULIN M) and various subclasses.
Polysaccharides consisting of mannose units.
An adhesion-promoting leukocyte surface membrane heterodimer. The alpha subunit consists of the CD11b ANTIGEN and the beta subunit the CD18 ANTIGEN. The antigen, which is an integrin, functions both as a receptor for complement 3 and in cell-cell and cell-substrate adhesive interactions.
Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).
Amyloid P component is a small, non-fibrillar glycoprotein found in normal serum and in all amyloid deposits. It has a pentagonal (pentaxin) structure. It is an acute phase protein, modulates immunologic responses, inhibits ELASTASE, and has been suggested as an indicator of LIVER DISEASE.
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
A subclass of lectins that are specific for CARBOHYDRATES that contain MANNOSE.
The clear portion of BLOOD that is left after BLOOD COAGULATION to remove BLOOD CELLS and clotting proteins.
Antibodies produced by a single clone of cells.
A group of naturally occurring N-and O-acyl derivatives of the deoxyamino sugar neuraminic acid. They are ubiquitously distributed in many tissues.
Chronic glomerulonephritis characterized histologically by proliferation of MESANGIAL CELLS, increase in the MESANGIAL EXTRACELLULAR MATRIX, and a thickening of the glomerular capillary walls. This may appear as a primary disorder or secondary to other diseases including infections and autoimmune disease SYSTEMIC LUPUS ERYTHEMATOSUS. Various subtypes are classified by their abnormal ultrastructures and immune deposits. Hypocomplementemia is a characteristic feature of all types of MPGN.
Any of the ruminant mammals with curved horns in the genus Ovis, family Bovidae. They possess lachrymal grooves and interdigital glands, which are absent in GOATS.
Inflammation of the renal glomeruli (KIDNEY GLOMERULUS) that can be classified by the type of glomerular injuries including antibody deposition, complement activation, cellular proliferation, and glomerulosclerosis. These structural and functional abnormalities usually lead to HEMATURIA; PROTEINURIA; HYPERTENSION; and RENAL INSUFFICIENCY.
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
A specific immune response elicited by a specific dose of an immunologically active substance or cell in an organism, tissue, or cell.
The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring ANTI-INFECTIVE AGENTS, constitutional factors such as BODY TEMPERATURE and immediate acting immune cells such as NATURAL KILLER CELLS.
The rate dynamics in chemical or physical systems.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
An endogenous 105-kDa plasma glycoprotein produced primarily by the LIVER and MONOCYTES. It inhibits a broad spectrum of proteases, including the COMPLEMENT C1R and the COMPLEMENT C1S proteases of the CLASSICAL COMPLEMENT PATHWAY, and the MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. C1-INH-deficient individuals suffer from HEREDITARY ANGIOEDEMA TYPES I AND II.
An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.
Substances elaborated by bacteria that have antigenic activity.
A mitosporic Tremellales fungal genus whose species usually have a capsule and do not form pseudomycellium. Teleomorphs include Filobasidiella and Fidobasidium.
Poisonous animal secretions forming fluid mixtures of many different enzymes, toxins, and other substances. These substances are produced in specialized glands and secreted through specialized delivery systems (nematocysts, spines, fangs, etc.) for disabling prey or predator.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Proteins prepared by recombinant DNA technology.
Established cell cultures that have the potential to propagate indefinitely.
The body fluid that circulates in the vascular system (BLOOD VESSELS). Whole blood includes PLASMA and BLOOD CELLS.
Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)
The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
A species of the fungus CRYPTOCOCCUS. Its teleomorph is Filobasidiella neoformans.
A genus of gram-negative, anaerobic, rod-shaped bacteria. Its organisms are normal inhabitants of the oral, respiratory, intestinal, and urogenital cavities of humans, animals, and insects. Some species may be pathogenic.
Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.
Proteins found in any species of bacterium.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.
A hexose or fermentable monosaccharide and isomer of glucose from manna, the ash Fraxinus ornus and related plants. (From Grant & Hackh's Chemical Dictionary, 5th ed & Random House Unabridged Dictionary, 2d ed)
The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.
A biosensing technique in which biomolecules capable of binding to specific analytes or ligands are first immobilized on one side of a metallic film. Light is then focused on the opposite side of the film to excite the surface plasmons, that is, the oscillations of free electrons propagating along the film's surface. The refractive index of light reflecting off this surface is measured. When the immobilized biomolecules are bound by their ligands, an alteration in surface plasmons on the opposite side of the film is created which is directly proportional to the change in bound, or adsorbed, mass. Binding is measured by changes in the refractive index. The technique is used to study biomolecular interactions, such as antigen-antibody binding.
Local surface sites on antibodies which react with antigen determinant sites on antigens (EPITOPES.) They are formed from parts of the variable regions of FAB FRAGMENTS.
Physiologically inactive substances that can be converted to active enzymes.
Transport proteins that carry specific substances in the blood or across cell membranes.
A G-protein-coupled receptor that signals an increase in intracellular calcium in response to the potent ANAPHYLATOXIN peptide COMPLEMENT C5A.
The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)
Inbred BALB/c mice are a strain of laboratory mice that have been selectively bred to be genetically identical to each other, making them useful for scientific research and experiments due to their consistent genetic background and predictable responses to various stimuli or treatments.
Procedures, such as TISSUE CULTURE TECHNIQUES; mathematical models; etc., when used or advocated for use in place of the use of animals in research or diagnostic laboratories.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
The single layer of pigment-containing epithelial cells in the RETINA, situated closely to the tips (outer segments) of the RETINAL PHOTORECEPTOR CELLS. These epithelial cells are macroglia that perform essential functions for the photoreceptor cells, such as in nutrient transport, phagocytosis of the shed photoreceptor membranes, and ensuring retinal attachment.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
The processes triggered by interactions of ANTIBODIES with their ANTIGENS.
A chronic, relapsing, inflammatory, and often febrile multisystemic disorder of connective tissue, characterized principally by involvement of the skin, joints, kidneys, and serosal membranes. It is of unknown etiology, but is thought to represent a failure of the regulatory mechanisms of the autoimmune system. The disease is marked by a wide range of system dysfunctions, an elevated erythrocyte sedimentation rate, and the formation of LE cells in the blood or bone marrow.
Elements of limited time intervals, contributing to particular results or situations.
A species of gram-negative, aerobic BACTERIA. It is a commensal and pathogen only of humans, and can be carried asymptomatically in the NASOPHARYNX. When found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis (MENINGITIS, MENINGOCOCCAL). It is also found in venereal discharges and blood. There are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being A, B, C, Y, and W-135. Each serogroup can be further classified by serotype, serosubtype, and immunotype.
Univalent antigen-binding fragments composed of one entire IMMUNOGLOBULIN LIGHT CHAIN and the amino terminal end of one of the IMMUNOGLOBULIN HEAVY CHAINS from the hinge region, linked to each other by disulfide bonds. Fab contains the IMMUNOGLOBULIN VARIABLE REGIONS, which are part of the antigen-binding site, and the first IMMUNOGLOBULIN CONSTANT REGIONS. This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.
Adverse functional, metabolic, or structural changes in ischemic tissues resulting from the restoration of blood flow to the tissue (REPERFUSION), including swelling; HEMORRHAGE; NECROSIS; and damage from FREE RADICALS. The most common instance is MYOCARDIAL REPERFUSION INJURY.
Presence of warmth or heat or a temperature notably higher than an accustomed norm.
A plasma protein that circulates in increased amounts during inflammation and after tissue damage.
Bacterial polysaccharides that are rich in phosphodiester linkages. They are the major components of the cell walls and membranes of many bacteria.
An enzyme that catalyzes the hydrolysis of alpha-2,3, alpha-2,6-, and alpha-2,8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate. (From Enzyme Nomenclature, 1992)
Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.
Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.
Toxins closely associated with the living cytoplasm or cell wall of certain microorganisms, which do not readily diffuse into the culture medium, but are released upon lysis of the cells.
Therapeutic practices which are not currently considered an integral part of conventional allopathic medical practice. They may lack biomedical explanations but as they become better researched some (PHYSICAL THERAPY MODALITIES; DIET; ACUPUNCTURE) become widely accepted whereas others (humors, radium therapy) quietly fade away, yet are important historical footnotes. Therapies are termed as Complementary when used in addition to conventional treatments and as Alternative when used instead of conventional treatment.
Polysaccharides are complex carbohydrates consisting of long, often branched chains of repeating monosaccharide units joined together by glycosidic bonds, which serve as energy storage molecules (e.g., glycogen), structural components (e.g., cellulose), and molecular recognition sites in various biological systems.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Infections with bacteria of the species STREPTOCOCCUS PNEUMONIAE.
The sum of the weight of all the atoms in a molecule.
Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
Glycoproteins found on the membrane or surface of cells.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The agent of South American trypanosomiasis or CHAGAS DISEASE. Its vertebrate hosts are man and various domestic and wild animals. Insects of several species are vectors.
The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitized T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement.
The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Proteins isolated from the outer membrane of Gram-negative bacteria.
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory IgA (IMMUNOGLOBULIN A, SECRETORY) is the main immunoglobulin in secretions.
The measurement of infection-blocking titer of ANTISERA by testing a series of dilutions for a given virus-antiserum interaction end-point, which is generally the dilution at which tissue cultures inoculated with the serum-virus mixtures demonstrate cytopathology (CPE) or the dilution at which 50% of test animals injected with serum-virus mixtures show infectivity (ID50) or die (LD50).
A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.
Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
An immune response with both cellular and humoral components, directed against an allogeneic transplant, whose tissue antigens are not compatible with those of the recipient.
The relationship between the dose of an administered drug and the response of the organism to the drug.
A derivative of complement C5a, generated when the carboxy-terminal ARGININE is removed by CARBOXYPEPTIDASE B present in normal human serum. C5a des-Arg shows complete loss of spasmogenic activity though it retains some chemotactic ability (CHEMOATTRACTANTS).
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.

Interaction between terminal complement proteins C5b-7 and anionic phospholipids. (1/625)

We have recently shown that C5b-6 binds to the erythrocyte membrane via an ionic interaction with sialic acid before the addition of C7 and subsequent membrane insertion. In this study we assessed the role of anionic lipids in the binding of the terminal complement proteins to the membrane and the efficiency of subsequent hemolysis. Human erythrocytes were modified by insertion of dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylserine (DPPS), dipalmitoyl phosphatidylethanolamine (DPPE), or dipalmitoyl phosphatidic acid (DPPA). Lipid incorporation and the hemolytic assays were done in the presence of 100 micromol/L sodium orthovanadate to prevent enzymatic redistribution of lipid. We found that the neutral lipids, DPPC and DPPE, did not affect C5b-7 uptake or hemolysis by C5b-9. In contrast, the two acidic phospholipids, DPPS and DPPA, caused a dose-dependent increase in both lysis and C5b-7 uptake. We conclude that the presence of anionic lipids on the exterior face of the membrane increases C5b-7 uptake and subsequent hemolysis. It is known that sickle cell erythrocytes have increased exposure of phosphatidylserine on their external face and are abnormally sensitive to lysis by C5b-9. The data presented here provide a plausible mechanism for this increased sensitivity.  (+info)

Role of antibody and complement in opsonization of group B streptococci. (2/625)

A requirement for the classic complement pathway in opsonization of group B streptococci was observed by using both a chemiluminescence and a radiolabeled bacterial uptake technique. The classic pathway increased levels of opsonization for types Ia and II stock and wild strains and for some type III wild strains. In contrast, other type III wild strains and the type III stock strain had accelerated kinetics of uptake in the presence of an intact classic pathway, but the level of opsonization was unchanged from that with antibody alone. We could not demonstrate a significant role for the alternative pathway in opsonizing stock or wild strains of group B streptococci. Futhermore, electrophoretic and complement consumption analysis by hemolytic titration failed to reveal alternative pathway activation by the majority of strains of this group. Therapy aimed at supplying opsonins for these organisms will require the presence of type-specific antibody.  (+info)

Cutting edge: C1q protects against the development of glomerulonephritis independently of C3 activation. (3/625)

C1q-deficient (C1qa-/-) mice develop antinuclear Abs and glomerulonephritis (GN) characterized by multiple apoptotic bodies. To explore the contribution of C3 activation to the induction of spontaneous GN, C1qa-/- mice were crossed with factor B- and C2-deficient (H2-Bf/C2-/-) mice. GN was present in 64% of the 45 C1qa/H2-Bf/C2-/- mice compared with 8% of the 65 H2-Bf/C2-/- mice and none of the 24 wild-type controls. IgG was detected in the glomeruli of diseased C1qa/H2-Bf/C2-/- kidneys. However, glomerular staining for C3 was absent. Increased numbers of glomerular apoptotic bodies were detected in undiseased C1qa/H2-Bf/C2-/- kidneys. These findings support the hypothesis that C1q may play a role in the clearance of apoptotic cells without the necessity for C3 activation and demonstrate that the activation of C3 is not essential for the development of GN in this spontaneous model of lupus-like disease.  (+info)

The surface properties of Neisseria gonorrhoeae: determinants of susceptibility to antibody complement killing. (4/625)

Monovalent rabbit antisera were prepared to highly purified gonococcal lipopolysaccharide (LPS), to pili and to two major purified outer envelope proteins. All these antisera were free from significant specific IgM antibody and were standardized to 4 microgram specific IgG antibody per test, permitting accurate comparisons between the different gonococcal surface antigens as triggers of the complement-dependent bactericidal reaction. LPS was the most effective antigen at inducing a bactericidal response to homologous and heterologous gonococci, followed by the two individual outer envelope proteins. Pili were relatively ineffective. Strain P9 gonococci grown in vivo or which possessed a 'capsule' in vitro were more resistant to serum killing than the non-capsulated parent strain. One highly susceptible strain, F62, which was killed by complement in the absence of any LPS antibody, was able to directly activate complement by the alternative pathway.  (+info)

Alterations in C3 activation and binding caused by phosphorylation by a casein kinase released from activated human platelets. (5/625)

A casein kinase released from activated human platelets phosphorylates a number of plasma proteins extracellularly, and that activation of platelets in systemic lupus erythematosus patients parallels an increase in the phosphate content of plasma proteins, including C3. The present study was undertaken to characterize this platelet protein kinase and to further elucidate the effect(s) on C3 function of phosphorylation by platelet casein kinase. The phosphate content of human plasma C3 was increased from 0.15 to 0.60 mol phosphate/mol of C3 after platelet activation in whole blood or platelet-rich plasma. The platelet casein kinase was distinct from other casein kinases in terms of its dependence on cations, inhibition by specific protein kinase inhibitors, and immunological reactivity. C3 that had been phosphorylated with platelet casein kinase was tested for its susceptibility to cleavage by trypsin or the classical and alternative pathway convertases and its binding to EAC and IgG. Phosphorylation did not affect the cleavage of C3 into C3a and C3b, but the binding of fragments from phosphorylated C3 to EAC14oxy2 cells and to IgG in purified systems and in serum was increased by 1.6-4.5 times over that of unphosphorylated C3. A covariation was seen between the enhanced binding of C3 fragments to IgG after phosphorylation and an increased ratio of glycerol/glycine binding, from 2.0 for unphosphorylated C3 to 4.9 for phosphorylated C3. The present study suggests that an overall effect of phosphorylation of C3 by platelet casein kinase is to enhance the opsonization of immune complexes.  (+info)

Granzyme A initiates an alternative pathway for granule-mediated apoptosis. (6/625)

Granzyme (gzm) B-deficient cytotoxic lymphocytes (CTL) have a severe defect in the rapid induction of target cell apoptosis that is almost completely corrected by prolonged incubation of the CTL effectors and their targets. We show in this report that perforin-dependent, gzmB-independent cytotoxicity is caused by gzmA (or tightly linked genes). CTL deficient for gzmA and gzmB retain normal perforin function, but these CTL have a cytotoxic defect in vivo that is as severe as perforin-deficient CTL. Collectively, these results suggest that perforin provides target cell access and/or trafficking signals for the gzms, and that the gzms themselves deliver the lethal hits. The gzmA pathway appears to function independently from gzmB and may therefore provide a critical "back-up" system when gzmB is inhibited in the target cell.  (+info)

The influence of complement receptor type 1 (CD35) and decay-accelerating factor (CD55) on complement receptor type 2- (CD21) mediated alternative pathway activation by B cells. (7/625)

The influence of complement receptor type 1 (CR1; CD35) and decay-accelerating factor (DAF; CD55), both down-regulators of complement activation, on the complement receptor type 2- (CR2) mediated alternative pathway (AP) activation of complement on normal B cells, was assessed. The data indicate that, while neither DAF nor CR1 hinder the function of the AP convertase formed on CR2, CR1 plays a significant role in the remodelling of C3b fragments, generated by the convertase and deposited at secondary acceptor sites on the B-cell surface, such that they become suitable ligands for CR2. The significance of this finding is briefly discussed.  (+info)

Calcium-independent haemolysis via the lectin pathway of complement activation in the guinea-pig and other species*. (8/625)

We previously reported that complement-dependent haemolysis of sheep erythrocytes (E) coated with mannan (M) and sensitized with human mannan-binding lectin (MBL) via the lectin pathway in man occurs in Mg-EGTA and requires alternative pathway amplification. Calcium was required for MBL binding to E-M, but once the E-M-MBL intermediate was formed, MBL was retained and haemolysis occurred in the absence of calcium. Comparable or greater lectin pathway haemolysis in the absence of calcium was observed upon incubation of E-M-MBL in guinea-pig, rat, dog and pig sera, and was further investigated in the guinea-pig, in which titres were much higher ( approximately 14-fold) than in man, and in contrast to humans, greater than classical pathway haemolytic activity. As in human serum, no lysis was observed in C4- or C2-deficient guinea-pig serum until purified C4 or C2, respectively, were restored. However, lectin pathway haemolytic activity in the guinea-pig did not require the alternative pathway. Removal (>98%) of factor D activity by three sequential passages through Sephadex G-75, resulting in serum which retained a normal classical pathway but no alternative pathway haemolytic activity, did not reduce the ability of guinea-pig serum to mediate haemolysis via the lectin pathway. Further, the C3-convertase formed via the lectin pathway (E-M-MBL-C4,2) lysed in C2-deficient guinea-pig but not human serum chelated with EDTA, a condition which precludes alternative pathway amplification. Thus, lectin pathway haemolysis occurs efficiently in guinea-pig serum, in the absence of calcium and without requirement for alternative pathway amplification. The guinea-pig provides a model for studying the assembly and haemolytic function of a lectin pathway which contrasts with the lectin pathway of man, and allows for comparisons that may help clarify the role of this pathway in complement biology.  (+info)

The alternative complement pathway is one of the three initiating pathways of the complement system, which is a part of the innate immune system that helps to clear pathogens and damaged cells from the body. The other two pathways are the classical and lectin pathways.

The alternative pathway is continuously activated at a low level, even in the absence of infection or injury, through the spontaneous cleavage of complement component C3 into C3a and C3b by the protease factor D in the presence of magnesium ions. The generated C3b can then bind covalently to nearby surfaces, including pathogens and host cells.

On self-surfaces, regulatory proteins like decay-accelerating factor (DAF) or complement receptor 1 (CR1) help to prevent the formation of the alternative pathway convertase and thus further activation of the complement system. However, on foreign surfaces, the C3b can recruit more complement components, forming a complex called the alternative pathway convertase (C3bBb), which cleaves additional C3 molecules into C3a and C3b.

The generated C3b can then bind to the surface and participate in the formation of the membrane attack complex (MAC), leading to the lysis of the target cell. The alternative pathway plays a crucial role in the defense against gram-negative bacteria, fungi, and parasites, as well as in the clearance of immune complexes and apoptotic cells. Dysregulation of the alternative complement pathway has been implicated in several diseases, including autoimmune disorders and atypical hemolytic uremic syndrome (aHUS).

The "Classical Complement Pathway" is one of the three pathways that make up the complement system, which is a part of the immune system in humans and other animals. The complement system helps to enhance the ability of antibodies and phagocytic cells to clear pathogens from the body.

The Classical Complement Pathway is initiated by the binding of the first component of the complement system, C1, to an activator surface, such as an antigen-antibody complex. Activation of C1 results in the sequential activation of other components of the complement system, including C4 and C2, which form the C3 convertase (C4b2a). The C3 convertase cleaves the third component of the complement system, C3, into C3a and C3b. C3b then binds to the activator surface and forms a complex with other components of the complement system, leading to the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, causing its lysis.

The Classical Complement Pathway plays an important role in the immune response to pathogens and can also contribute to inflammation and tissue damage in certain diseases, such as autoimmune disorders and allergies.

Complement activation is the process by which the complement system, a part of the immune system, is activated to help eliminate pathogens and damaged cells from the body. The complement system consists of a group of proteins that work together to recognize and destroy foreign substances.

Activation of the complement system can occur through three different pathways: the classical pathway, the lectin pathway, and the alternative pathway. Each pathway involves a series of proteolytic reactions that ultimately result in the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, leading to its lysis and removal.

The classical pathway is typically activated by the binding of antibodies to antigens on the surface of a pathogen or damaged cell. The lectin pathway is activated by the recognition of specific carbohydrate structures on the surface of microorganisms. The alternative pathway can be spontaneously activated and serves as an amplification loop for both the classical and lectin pathways.

Complement activation plays a crucial role in the immune response, but uncontrolled or excessive activation can also lead to tissue damage and inflammation. Dysregulation of complement activation has been implicated in various diseases, including autoimmune disorders, inflammatory conditions, and neurodegenerative diseases.

Complement C3 is a protein that plays a central role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Complement C3 can be activated through three different pathways: the classical pathway, the lectin pathway, and the alternative pathway. Once activated, it breaks down into two fragments, C3a and C3b.

C3a is an anaphylatoxin that helps to recruit immune cells to the site of infection or injury, while C3b plays a role in opsonization, which is the process of coating pathogens or damaged cells with proteins to make them more recognizable to the immune system. Additionally, C3b can also activate the membrane attack complex (MAC), which forms a pore in the membrane of target cells leading to their lysis or destruction.

In summary, Complement C3 is an important protein in the complement system that helps to identify and eliminate pathogens and damaged cells from the body through various mechanisms.

The complement system is a group of proteins found in the blood and on the surface of cells that when activated, work together to help eliminate pathogens such as bacteria, viruses, and fungi from the body. The proteins are normally inactive in the bloodstream. When they encounter an invading microorganism or foreign substance, a series of reactions take place leading to the activation of the complement system. Activation results in the production of effector molecules that can punch holes in the cell membranes of pathogens, recruit and activate immune cells, and help remove debris and dead cells from the body.

There are three main pathways that can lead to complement activation: the classical pathway, the lectin pathway, and the alternative pathway. Each pathway involves a series of proteins that work together in a cascade-like manner to amplify the response and generate effector molecules. The three main effector molecules produced by the complement system are C3b, C4b, and C5b. These molecules can bind to the surface of pathogens, marking them for destruction by other immune cells.

Complement proteins also play a role in the regulation of the immune response. They help to prevent excessive activation of the complement system, which could damage host tissues. Dysregulation of the complement system has been implicated in a number of diseases, including autoimmune disorders and inflammatory conditions.

In summary, Complement System Proteins are a group of proteins that play a crucial role in the immune response by helping to eliminate pathogens and regulate the immune response. They can be activated through three different pathways, leading to the production of effector molecules that mark pathogens for destruction. Dysregulation of the complement system has been linked to various diseases.

Complement C4 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Complement C4 is involved in the early stages of the complement activation cascade, where it helps to identify and tag foreign or abnormal cells for destruction by other components of the immune system.

Specifically, Complement C4 can be cleaved into two smaller proteins, C4a and C4b, during the complement activation process. C4b then binds to the surface of the target cell and helps to initiate the formation of the membrane attack complex (MAC), which creates a pore in the cell membrane and leads to lysis or destruction of the target cell.

Deficiencies or mutations in the Complement C4 gene can lead to various immune disorders, including certain forms of autoimmune diseases and susceptibility to certain infections.

Complement Factor B is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, Factor B is a component of the alternative pathway of the complement system, which provides a rapid and amplified response to microbial surfaces.

Factor B is cleaved by another protease called Factor D into two fragments, Ba and Bb. The formation of the C3 convertase (C3bBb) is essential for the activation of the alternative pathway. This complex can cleave and activate more C3 molecules, leading to a cascade of reactions that result in the formation of the membrane attack complex (MAC), which forms pores in the membranes of target cells, causing their lysis and elimination.

Deficiencies or mutations in Complement Factor B can lead to various complement-mediated diseases, such as atypical hemolytic uremic syndrome (aHUS) and age-related macular degeneration (AMD).

Complement C1q is a protein that is part of the complement system, which is a group of proteins in the blood that help to eliminate pathogens and damaged cells from the body. C1q is the first component of the classical complement pathway, which is activated by the binding of C1q to antibodies that are attached to the surface of a pathogen or damaged cell.

C1q is composed of six identical polypeptide chains, each containing a collagen-like region and a globular head region. The globular heads can bind to various structures, including the Fc regions of certain antibodies, immune complexes, and some types of cells. When C1q binds to an activating surface, it triggers a series of proteolytic reactions that lead to the activation of other complement components and the formation of the membrane attack complex (MAC), which can punch holes in the membranes of pathogens or damaged cells, leading to their destruction.

In addition to its role in the immune system, C1q has also been found to have roles in various physiological processes, including tissue remodeling, angiogenesis, and the clearance of apoptotic cells. Dysregulation of the complement system, including abnormalities in C1q function, has been implicated in a variety of diseases, including autoimmune disorders, inflammatory diseases, and neurodegenerative conditions.

The Mannose-Binding Lectin (MBL) pathway is a part of the complement system, which is a group of proteins that play a crucial role in the body's immune defense against infectious agents. The MBL pathway is an alternative activation pathway of the complement system, which can be initiated without the need for antibodies.

MBL is a protein found in blood plasma and other bodily fluids. It recognizes and binds to specific sugars (mannose and fucose) found on the surface of many microorganisms, including bacteria, viruses, fungi, and parasites. When MBL binds to these sugars, it triggers a series of proteolytic cleavage events that activate the complement components C4 and C2, forming the C3 convertase (C4b2a).

The C3 convertase then cleaves the complement component C3 into C3a and C3b. C3b can bind to the surface of microorganisms, leading to their opsonization (coating) and subsequent phagocytosis by immune cells. Additionally, C3b can also trigger the formation of the membrane attack complex (MAC), which creates a pore in the membrane of microorganisms, leading to their lysis and death.

Overall, the MBL pathway plays an essential role in innate immunity, providing a rapid and effective defense against invading microorganisms.

Complement C2 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, C2 is a component of the classical complement pathway, which is activated by the binding of antibodies to antigens on the surface of foreign particles or cells.

When the classical pathway is activated, C2 is cleaved into two fragments: C2a and C2b. C2a then binds to C4b to form the C3 convertase (C4b2a), which cleaves C3 into C3a and C3b. C3b can then go on to form the membrane attack complex, which creates a pore in the membrane of the target cell, leading to its lysis.

In summary, Complement C2 is a protein that helps to activate the complement system and destroy foreign particles or cells through the formation of the C3 convertase and the membrane attack complex.

Complement C3b is a protein fragment that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. C3b is generated during the activation of the complement system, particularly via the classical, lectin, and alternative pathways.

Once formed, C3b can bind covalently to the surface of microbes or other target particles, marking them for destruction by other components of the immune system. Additionally, C3b can interact with other proteins in the complement system to generate the membrane attack complex (MAC), which forms pores in the membranes of targeted cells, leading to their lysis and removal.

In summary, Complement C3b is a vital protein fragment involved in the recognition, tagging, and elimination of pathogens and damaged cells during the immune response.

Complement C1 is a protein complex that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. The complement system consists of a group of proteins that work together to destroy microbes and remove debris.

Complement C1 is composed of three subunits: C1q, C1r, and C1s. When activated, C1q binds to the surface of a pathogen or damaged cell, leading to the activation of C1r and C1s. Activated C1r then cleaves and activates C1s, which in turn cleaves and activates other complement components, ultimately resulting in the formation of the membrane attack complex (MAC), a protein structure that forms a pore in the membrane of the target cell, leading to its lysis and destruction.

Defects in the complement component C1 can lead to immune disorders, such as hereditary angioedema, which is characterized by recurrent episodes of swelling in various parts of the body.

Complement C5 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. The complement system is a complex series of biochemical reactions that help to identify and destroy foreign substances, such as bacteria and viruses.

Complement C5 is one of several proteins in the complement system that are activated in a cascading manner in response to an activating event, such as the binding of an antibody to a pathogen. Once activated, Complement C5 can be cleaved into two smaller proteins, C5a and C5b.

C5a is a powerful anaphylatoxin, which means it can cause the release of histamine from mast cells and basophils, leading to inflammation and increased vascular permeability. It also acts as a chemoattractant, drawing immune cells to the site of infection or injury.

C5b, on the other hand, plays a role in the formation of the membrane attack complex (MAC), which is a protein structure that can punch holes in the membranes of pathogens, leading to their lysis and destruction.

Overall, Complement C5 is an important component of the immune system's response to infection and injury, helping to eliminate pathogens and damaged cells from the body.

Complement inactivator proteins are a group of regulatory proteins that help to control and limit the activation of the complement system, which is a part of the immune system. The complement system is a complex series of biochemical reactions that help to eliminate pathogens and damaged cells from the body. However, if not properly regulated, the complement system can also cause damage to healthy tissues and contribute to the development of various diseases.

Complement inactivator proteins work by inhibiting specific components of the complement system, preventing them from activating and causing an immune response. Some examples of complement inactivator proteins include:

1. C1 inhibitor (C1INH): This protein regulates the activation of the classical pathway of the complement system by inhibiting the C1 complex, which is a group of proteins that initiate this pathway.
2. Decay-accelerating factor (DAF or CD55): This protein regulates the activation of both the classical and alternative pathways of the complement system by accelerating the decay of the C3/C5 convertases, which are enzymes that activate the complement components C3 and C5.
3. Membrane cofactor protein (MCP or CD46): This protein regulates the activation of the alternative pathway of the complement system by serving as a cofactor for the cleavage and inactivation of C3b, a component of the C3 convertase.
4. Factor H: This protein also regulates the activation of the alternative pathway of the complement system by acting as a cofactor for the cleavage and inactivation of C3b, and by preventing the formation of the C3 convertase.

Deficiencies or dysfunction of complement inactivator proteins can lead to various diseases, including hereditary angioedema (C1INH deficiency), atypical hemolytic uremic syndrome (factor H deficiency or dysfunction), and age-related macular degeneration (complement component overactivation).

Complement Factor D is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, Factor D is a serine protease that is involved in the alternative pathway of the complement system.

In this pathway, Factor D helps to cleave another protein called Factor B, which then activates a complex called the C3 convertase. The C3 convertase cleaves complement component 3 (C3) into C3a and C3b, leading to the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, causing its lysis and removal from the body.

Deficiencies or mutations in Complement Factor D can lead to an impaired alternative pathway and increased susceptibility to certain infections, particularly those caused by Neisseria bacteria. Additionally, abnormal regulation of the complement system has been implicated in a variety of diseases, including autoimmune disorders, inflammatory conditions, and neurodegenerative diseases.

Complement C3-C5 convertases are proteins that play a crucial role in the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by marking them for destruction and attracting immune cells to the site of infection or injury.

The C3-C5 convertases are formed during the activation of the complement component 3 (C3) protein, which is a central player in the complement system. The formation of the C3-C5 convertase involves two main steps:

1. C3 convertase formation: In this step, a complex of proteins called the C3 convertase is formed by the cleavage of C3 into C3a and C3b fragments. This complex can then cleave additional C3 molecules into C3a and C3b fragments, amplifying the complement response.
2. C5 convertase formation: In this step, the C3b fragment from the C3 convertase binds to another protein called C4b2a, forming a new complex called the C5 convertase. The C5 convertase can then cleave the C5 protein into C5a and C5b fragments.

The C5b fragment goes on to form the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, leading to its lysis or destruction. The C3a and C5a fragments are small proteins called anaphylatoxins that can cause inflammation and attract immune cells to the site of infection or injury.

Overall, the formation of Complement C3-C5 convertases is a critical step in the activation of the complement system and plays a key role in the body's defense against pathogens and damaged cells.

Properdin is defined as a positive regulatory protein in the complement system, which is a part of the immune system. It plays a crucial role in the alternative pathway of complement activation. Properdin stabilizes the C3 convertase (C3bBb), preventing its decay and increasing the efficiency of the alternative pathway. This results in the production of the membrane attack complex, which leads to the lysis of foreign cells or pathogens. Deficiencies in properdin can lead to an increased susceptibility to bacterial infections.

Complement Factor H is a protein involved in the regulation of the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, Complement Factor H helps to regulate the activation and deactivation of the complement component C3b, preventing excessive or unwanted activation of the complement system and protecting host tissues from damage.

Complement Factor H is a crucial protein in maintaining the balance between the protective effects of the complement system and the potential for harm to the body's own cells and tissues. Deficiencies or mutations in Complement Factor H have been associated with several diseases, including age-related macular degeneration (AMD), atypical hemolytic uremic syndrome (aHUS), and C3 glomerulopathy.

Complement receptors are proteins found on the surface of various cells in the human body, including immune cells and some non-immune cells. They play a crucial role in the complement system, which is a part of the innate immune response that helps to eliminate pathogens and damaged cells from the body. Complement receptors bind to complement proteins or fragments that are generated during the activation of the complement system. This binding triggers various intracellular signaling events that can lead to diverse cellular responses, such as phagocytosis, inflammation, and immune regulation.

There are several types of complement receptors, including:

1. CR1 (CD35): A receptor found on erythrocytes, B cells, neutrophils, monocytes, macrophages, and glomerular podocytes. It functions in the clearance of immune complexes and regulates complement activation.
2. CR2 (CD21): Expressed mainly on B cells and follicular dendritic cells. It facilitates antigen presentation, B-cell activation, and immune regulation.
3. CR3 (CD11b/CD18, Mac-1): Present on neutrophils, monocytes, macrophages, and some T cells. It mediates cell adhesion, phagocytosis, and intracellular signaling.
4. CR4 (CD11c/CD18, p150,95): Expressed on neutrophils, monocytes, macrophages, and dendritic cells. It is involved in cell adhesion, phagocytosis, and intracellular signaling.
5. C5aR (CD88): Found on various immune cells, including neutrophils, monocytes, macrophages, mast cells, eosinophils, and dendritic cells. It binds to the complement protein C5a and mediates chemotaxis, degranulation, and inflammation.
6. C5L2 (GPR77): Present on various cell types, including immune cells. Its function is not well understood but may involve regulating C5a-mediated responses or acting as a receptor for other ligands.

These receptors play crucial roles in the immune response and inflammation by mediating various functions such as chemotaxis, phagocytosis, cell adhesion, and intracellular signaling. Dysregulation of these receptors has been implicated in several diseases, including autoimmune disorders, infections, and cancer.

The Complement Membrane Attack Complex (MAC), also known as the Terminal Complement Complex (TCC), is a protein structure that forms in the final stages of the complement system's immune response. The complement system is a part of the innate immune system that helps to eliminate pathogens and damaged cells from the body.

The MAC is composed of several proteins, including C5b, C6, C7, C8, and multiple subunits of C9, which assemble on the surface of target cells. The formation of the MAC creates a pore-like structure in the cell membrane, leading to disruption of the membrane's integrity and ultimately causing cell lysis or damage.

The MAC plays an important role in the immune response by helping to eliminate pathogens that have evaded other immune defenses. However, uncontrolled activation of the complement system and formation of the MAC can also contribute to tissue damage and inflammation in various diseases, such as autoimmune disorders, age-related macular degeneration, and ischemia-reperfusion injury.

Complement C6 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, C6 is a component of the membrane attack complex (MAC), which is a group of proteins that work together to form a pore in the membrane of target cells, leading to their lysis or destruction.

The complement system is activated through several different pathways, including the classical pathway, the lectin pathway, and the alternative pathway. Once activated, these pathways converge at the level of C3, which is cleaved into C3a and C3b fragments. C3b can then bind to the surface of target cells and initiate the formation of the MAC.

C6 is one of several proteins that are required for the formation of the MAC. When C6 binds to C7, it undergoes a conformational change that allows it to interact with C8 and form a stable complex. This complex then recruits additional C9 molecules, which polymerize to form the pore in the target cell membrane.

Deficiencies in complement components, including C6, can lead to increased susceptibility to certain types of infections, as well as autoimmune disorders and other medical conditions.

Complement C4b is a protein fragment that is formed during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by tagging them for destruction and attracting immune cells to the site of infection or injury.

C4b is generated when the C4 protein is cleaved into two smaller fragments, C4a and C4b, during the activation of the classical or lectin pathways of the complement system. C4b then binds covalently to the surface of the target cell or pathogen, forming a complex with other complement proteins that can create a membrane attack complex (MAC) and cause cell lysis.

C4b can also act as an opsonin, coating the surface of the target cell or pathogen and making it easier for immune cells to recognize and phagocytose them. Additionally, C4b can activate the alternative pathway of the complement system, leading to further amplification of the complement response.

Complement C3b inactivator proteins, also known as complement regulators or decay-accelerating factor (DAF), are a group of proteins that play a crucial role in regulating the complement system. The complement system is a part of the immune system that helps to eliminate pathogens and damaged cells from the body.

The complement C3b inactivator proteins include two main types: complement receptor 1 (CR1) and decay-accelerating factor (DAF). These proteins work by regulating the formation of the membrane attack complex (MAC), a protein structure that forms pores in the cell membrane, leading to cell lysis.

Complement C3b inactivator proteins bind to C3b and C4b components of the complement system, preventing them from forming the MAC. By doing so, they help to prevent excessive activation of the complement system, which can damage healthy cells and tissues.

Deficiencies or dysfunction of complement C3b inactivator proteins have been associated with several diseases, including autoimmune disorders, inflammatory diseases, and infectious diseases. Therefore, understanding the role of these proteins in regulating the complement system is essential for developing new therapies to treat these conditions.

Complement activating enzymes are proteins that play a crucial role in the activation of the complement system, which is a part of the immune system. The complement system is a complex series of biochemical reactions that help to eliminate pathogens and damaged cells from the body.

There are several types of complement activating enzymes, including:

1. Classical pathway activators: These include the C1, C4, and C2 components of the complement system. When activated, they trigger a series of reactions that lead to the formation of the membrane attack complex (MAC), which creates a pore in the membrane of the target cell, leading to its lysis.
2. Alternative pathway activators: These include factors B, D, and P. They are constantly active at low levels and can be activated by surfaces that are not normally found in the body, such as bacterial cell walls. Once activated, they also trigger the formation of the MAC.
3. Lectin pathway activators: These include mannose-binding lectin (MBL) and ficolins. They bind to carbohydrates on the surface of microbes and activate the complement system through the MBL-associated serine proteases (MASPs).

Overall, complement activating enzymes play a critical role in the immune response by helping to identify and eliminate pathogens and damaged cells from the body.

A Complement Hemolytic Activity Assay is a laboratory test used to measure the functionality and activity level of the complement system, which is a part of the immune system. The complement system is a group of proteins that work together to help eliminate pathogens from the body.

The assay measures the ability of the complement system to lyse (break open) red blood cells. This is done by mixing the patient's serum (the liquid portion of the blood) with antibody-coated red blood cells and incubating them together. The complement proteins in the serum will then bind to the antibodies on the red blood cells and cause them to lyse.

The degree of hemolysis (red blood cell lysis) is directly proportional to the activity level of the complement system. By measuring the amount of hemolysis, the assay can determine whether the complement system is functioning properly and at what level of activity.

This test is often used to diagnose or monitor complement-mediated diseases such as autoimmune disorders, infections, and some types of cancer. It may also be used to evaluate the effectiveness of treatments that target the complement system.

Complement C9 is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, C9 is one of the components of the membrane attack complex (MAC), which is a protein structure that forms pores in the membranes of target cells, leading to their lysis or destruction.

When activated, C9 polymerizes and inserts itself into the cell membrane, forming a transmembrane pore that disrupts the membrane's integrity and causes the cell to lyse. This process is an essential part of the complement system's ability to destroy pathogens and clear damaged cells from the body.

Defects in the C9 gene can lead to a rare genetic disorder called complement component 9 deficiency, which is characterized by recurrent bacterial infections and immune complex-mediated diseases. Additionally, mutations in the C9 gene have been associated with an increased risk of age-related macular degeneration (AMD), a leading cause of blindness in older adults.

Complement inactivating agents are substances or drugs that inhibit the complement system, which is a part of the immune system responsible for the recognition and elimination of foreign substances and microorganisms. The complement system consists of a group of proteins that work together to help eliminate pathogens from the body.

Complement inactivating agents are used in medical settings to prevent or treat various conditions associated with excessive or unwanted activation of the complement system, such as inflammation, autoimmune diseases, and transplant rejection. These agents can inhibit different components of the complement pathway, including C1 esterase inhibitors, C3 convertase inhibitors, and C5a receptor antagonists.

Examples of complement inactivating agents include eculizumab, ravulizumab, and Alexion's Ultomiris, which are monoclonal antibodies that target C5, a protein involved in the final steps of the complement pathway. These drugs have been approved for the treatment of paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and other complement-mediated diseases.

Other complement inactivating agents include C1 esterase inhibitors, such as Berinert and Ruconest, which are used to treat hereditary angioedema (HAE). These drugs work by inhibiting the activation of the classical pathway of the complement system, thereby preventing the release of inflammatory mediators that can cause swelling and pain.

Overall, complement inactivating agents play an important role in the treatment of various complement-mediated diseases, helping to reduce inflammation, prevent tissue damage, and improve patient outcomes.

Alternative splicing is a process in molecular biology that occurs during the post-transcriptional modification of pre-messenger RNA (pre-mRNA) molecules. It involves the removal of non-coding sequences, known as introns, and the joining together of coding sequences, or exons, to form a mature messenger RNA (mRNA) molecule that can be translated into a protein.

In alternative splicing, different combinations of exons are selected and joined together to create multiple distinct mRNA transcripts from a single pre-mRNA template. This process increases the diversity of proteins that can be produced from a limited number of genes, allowing for greater functional complexity in organisms.

Alternative splicing is regulated by various cis-acting elements and trans-acting factors that bind to specific sequences in the pre-mRNA molecule and influence which exons are included or excluded during splicing. Abnormal alternative splicing has been implicated in several human diseases, including cancer, neurological disorders, and cardiovascular disease.

Mannose-binding protein-associated serine proteases (MASPs) are a group of enzymes that are associated with mannose-binding lectin (MBL), a protein involved in the innate immune system's response to pathogens. MASPs are responsible for activating the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body.

MASPs are proteases, meaning they cleave other proteins at specific sites. There are two main types of MASPs, MASP-1 and MASP-2, which are activated by the binding of MBL to carbohydrate structures on the surface of pathogens. Once activated, MASP-1 and MASP-2 cleave complement components C4 and C2, leading to the formation of the C3 convertase enzyme complex, which ultimately results in the activation of the complement system.

MASPs have also been shown to play a role in other physiological processes, such as tissue remodeling and inflammation. Mutations in MASP genes have been associated with various immune disorders, including recurrent infections, autoimmune diseases, and inflammatory conditions.

Complement C3a is a protein fragment that is generated during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by marking them for destruction and attracting immune cells to the site of infection or injury.

C3a is produced when the third component of the complement system (C3) is cleaved into two smaller fragments, C3a and C3b, during the complement activation cascade. C3a is a potent anaphylatoxin, which means it can cause the release of histamine and other mediators from mast cells and basophils, leading to inflammation, increased vascular permeability, and smooth muscle contraction.

C3a also has chemotactic properties, meaning it can attract immune cells such as neutrophils and monocytes to the site of complement activation. Additionally, C3a can modulate the activity of various immune cells, including dendritic cells, T cells, and B cells, and play a role in the regulation of the adaptive immune response.

It's important to note that while C3a has important functions in the immune response, uncontrolled or excessive activation of the complement system can lead to tissue damage and inflammation, contributing to the pathogenesis of various diseases such as autoimmune disorders, inflammatory diseases, and allergies.

Mannose-Binding Lectin (MBL) is a protein that belongs to the collectin family and plays a crucial role in the innate immune system. It's primarily produced by the liver and secreted into the bloodstream. MBL binds to carbohydrate structures, such as mannose, found on the surface of various microorganisms, including bacteria, viruses, fungi, and parasites.

Once MBL binds to these microorganisms, it activates the complement system through the lectin pathway, which leads to the destruction of the pathogens by opsonization (marking for phagocytosis) or direct lysis. Additionally, MBL can also initiate other immune responses, such as inflammation and immune cell activation, helping to protect the host from infections.

Deficiencies in MBL have been associated with increased susceptibility to certain infectious diseases, autoimmune disorders, and allergies. However, more research is needed to fully understand the complex role of MBL in human health and disease.

Complement C3c is a protein component of the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Complement C3c is formed when the third component of the complement system (C3) is cleaved into two smaller proteins, C3a and C3b, during the complement activation process.

C3b can then be further cleaved into C3c and C3dg. C3c is a stable fragment that remains in the circulation and can be measured in blood tests as a marker of complement activation. It plays a role in the opsonization of pathogens, which means it coats them to make them more recognizable to immune cells, and helps to initiate the membrane attack complex (MAC), which forms a pore in the cell membrane of pathogens leading to their lysis or destruction.

Abnormal levels of C3c may indicate an underlying inflammatory or immune-mediated condition, such as infection, autoimmune disease, or cancer.

Complement C1 Inactivator proteins are a part of the complement system, which is a group of proteins in the blood that play a crucial role in the body's immune defense system. Specifically, Complement C1 Inactivator proteins are responsible for regulating the activation of the first component of the complement system, C1.

The complement system is activated in response to the presence of foreign substances such as bacteria or viruses in the body. The activation of C1 leads to a cascade of reactions that result in the destruction of the foreign substance. However, if this process is not properly regulated, it can lead to damage to the body's own cells and tissues.

Complement C1 Inactivator proteins help to prevent this by regulating the activation of C1. They do this by binding to and inhibiting the activity of C1, preventing it from initiating the complement cascade. A deficiency in Complement C1 Inactivator proteins can lead to a condition called hereditary angioedema, which is characterized by recurrent episodes of swelling in various parts of the body.

Complement C3d is a protein fragment that is formed during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens such as bacteria and viruses from the body by tagging them for destruction and attracting immune cells to the site of infection.

C3d is a cleavage product of complement component C3, which is one of the central proteins in the complement system. When C3 is activated, it is cleaved into two fragments: C3a and C3b. C3b can then be further cleaved into C3d and C3c.

C3d plays a role in the activation of the immune system by helping to link the complement system with the adaptive immune response. It does this by binding to receptors on B cells, which are a type of white blood cell that produces antibodies. This interaction can help to stimulate the production of antibodies and enhance the immune response to pathogens.

C3d has also been implicated in the development of certain autoimmune diseases, as it can contribute to the formation of immune complexes that can cause tissue damage.

Complement C5a is a protein fragment that is generated during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by tagging them for destruction and attracting immune cells to the site of infection or injury.

C5a is formed when the fifth component of the complement system (C5) is cleaved into two smaller fragments, C5a and C5b, during the complement activation cascade. C5a is a potent pro-inflammatory mediator that can attract and activate various immune cells, such as neutrophils, monocytes, and eosinophils, to the site of infection or injury. It can also increase vascular permeability, promote the release of histamine, and induce the production of reactive oxygen species, all of which contribute to the inflammatory response.

However, excessive or uncontrolled activation of the complement system and generation of C5a can lead to tissue damage and inflammation, contributing to the pathogenesis of various diseases, such as sepsis, acute respiratory distress syndrome (ARDS), and autoimmune disorders. Therefore, targeting C5a or its receptors has been explored as a potential therapeutic strategy for these conditions.

Hemolysis is the destruction or breakdown of red blood cells, resulting in the release of hemoglobin into the surrounding fluid (plasma). This process can occur due to various reasons such as chemical agents, infections, autoimmune disorders, mechanical trauma, or genetic abnormalities. Hemolysis may lead to anemia and jaundice, among other complications. It is essential to monitor hemolysis levels in patients undergoing medical treatments that might cause this condition.

Opsonins are proteins found in the blood that help enhance the immune system's response to foreign substances, such as bacteria and viruses. They do this by coating the surface of these pathogens, making them more recognizable to immune cells like neutrophils and macrophages. This process, known as opsonization, facilitates the phagocytosis (engulfing and destroying) of the pathogen by these immune cells.

There are two main types of opsonins:

1. IgG antibodies: These are a type of antibody produced by the immune system in response to an infection. They bind to specific antigens on the surface of the pathogen, marking them for destruction by phagocytic cells.
2. Complement proteins: The complement system is a group of proteins that work together to help eliminate pathogens. When activated, the complement system can produce various proteins that act as opsonins, including C3b and C4b. These proteins bind to the surface of the pathogen, making it easier for phagocytic cells to recognize and destroy them.

In summary, opsonin proteins are crucial components of the immune system's response to infections, helping to mark foreign substances for destruction by immune cells like neutrophils and macrophages.

Blood bactericidal activity refers to the ability of an individual's blood to kill or inhibit the growth of bacteria. This is an important aspect of the body's immune system, as it helps to prevent infection and maintain overall health. The bactericidal activity of blood can be influenced by various factors, including the presence of antibodies, white blood cells (such as neutrophils), and complement proteins.

In medical terms, the term "bactericidal" specifically refers to an agent or substance that is capable of killing bacteria. Therefore, when we talk about blood bactericidal activity, we are referring to the collective ability of various components in the blood to kill or inhibit the growth of bacteria. This is often measured in laboratory tests as a way to assess a person's immune function and their susceptibility to infection.

It's worth noting that not all substances in the blood are bactericidal; some may simply inhibit the growth of bacteria without killing them. These substances are referred to as bacteriostatic. Both bactericidal and bacteriostatic agents play important roles in maintaining the body's defense against infection.

Complement receptor 3b (CR3b or CD11b/CD18) is not a medical definition itself, but I can provide you with the relevant information regarding this term.

Complement receptor 3 (CR3) is a heterodimeric receptor consisting of two subunits, CD11b (also known as Mac-1 or CR3 alpha) and CD18 (also known as beta2 integrin). There are two forms of the CD11b/CD18 heterodimer: CR3a (CD11b/CD18) and CR3b (CD11b/CD18'). The difference between these two forms lies in the conformation of the CD11b subunit.

Complement receptor 3b (CR3b or CD11b/CD18') is a less common form of the CR3 receptor, which is primarily expressed on myeloid cells such as monocytes, macrophages, and neutrophils. CR3b has a higher affinity for complement component C3b and its fragments iC3b and C3dg compared to CR3a.

CR3b plays a role in various immune functions, including:

1. Phagocytosis: Binding of C3b or its fragments to CR3b facilitates the recognition and uptake of opsonized pathogens by phagocytes.
2. Adhesion: The integrin component of CR3b mediates cell-cell and cell-matrix interactions, contributing to leukocyte migration and recruitment to sites of inflammation or infection.
3. Intracellular signaling: Activation of CR3b can lead to intracellular signaling events that modulate immune responses, such as the release of pro-inflammatory cytokines and reactive oxygen species.

In summary, Complement receptor 3b (CR3b or CD11b/CD18') is a less common form of CR3 primarily expressed on myeloid cells that binds complement component C3b and its fragments with high affinity, mediating phagocytosis, adhesion, and intracellular signaling.

Complement fixation tests are a type of laboratory test used in immunology and serology to detect the presence of antibodies in a patient's serum. These tests are based on the principle of complement activation, which is a part of the immune response. The complement system consists of a group of proteins that work together to help eliminate pathogens from the body.

In a complement fixation test, the patient's serum is mixed with a known antigen and complement proteins. If the patient has antibodies against the antigen, they will bind to it and activate the complement system. This results in the consumption or "fixation" of the complement proteins, which are no longer available to participate in a secondary reaction.

A second step involves adding a fresh source of complement proteins and a dye-labeled antibody that recognizes a specific component of the complement system. If complement was fixed during the first step, it will not be available for this secondary reaction, and the dye-labeled antibody will remain unbound. Conversely, if no antibodies were present in the patient's serum, the complement proteins would still be available for the second reaction, leading to the binding of the dye-labeled antibody.

The mixture is then examined under a microscope or using a spectrophotometer to determine whether the dye-labeled antibody has bound. If it has not, this indicates that the patient's serum contains antibodies specific to the antigen used in the test, and a positive result is recorded.

Complement fixation tests have been widely used for the diagnosis of various infectious diseases, such as syphilis, measles, and influenza. However, they have largely been replaced by more modern serological techniques, like enzyme-linked immunosorbent assays (ELISAs) and nucleic acid amplification tests (NAATs), due to their increased sensitivity, specificity, and ease of use.

Complement C1s is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, C1s is a component of the first protein complex in the classical complement pathway, called C1.

C1 is composed of three subunits: C1q, C1r, and C1s. When C1 encounters an activating surface, such as an antibody-antigen complex or certain types of viruses and bacteria, it undergoes a conformational change that allows C1r to cleave and activate C1s. Activated C1s then goes on to cleave and activate other components in the complement pathway, leading to the generation of the membrane attack complex (MAC) and subsequent lysis of the target cell.

Deficiencies or mutations in the genes encoding complement proteins, including C1s, can lead to various immune disorders and increased susceptibility to infections.

Complement Factor I is a protein involved in the regulation of the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, Complement Factor I is a serine protease that regulates the complement component C3b by cleaving it into inactive fragments, thereby preventing the excessive activation of the complement system and protecting host tissues from damage.

Complement Factor I functions in conjunction with other regulatory proteins, such as complement receptor 1 (CR1) and membrane cofactor protein (MCP), to control the activity of the complement system at various stages. Deficiencies or mutations in Complement Factor I have been associated with several diseases, including atypical hemolytic uremic syndrome (aHUS), age-related macular degeneration (AMD), and systemic lupus erythematosus (SLE).

Complement C4b-binding protein (C4bp) is a regulatory protein in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. C4bp regulates the complement system by binding to and inhibiting the activity of C4b, an activated component of the classical and lectin pathways of the complement system. By doing so, C4bp helps to prevent excessive or inappropriate activation of the complement system, which could otherwise lead to tissue damage and inflammation.

C4bp is a complex protein that consists of several subunits, including a central α-chain and multiple β-chains. It is produced by liver cells and can also be found on the surface of some cells in the body. Mutations in the genes encoding C4bp have been associated with certain immune disorders, such as systemic lupus erythematosus (SLE) and atypical hemolytic uremic syndrome (aHUS).

Zymosan is a type of substance that is derived from the cell walls of yeast and some types of fungi. It's often used in laboratory research as an agent to stimulate inflammation, because it can activate certain immune cells (such as neutrophils) and cause them to release pro-inflammatory chemicals.

In medical terms, Zymosan is sometimes used as a tool for studying the immune system and inflammation in experimental settings. It's important to note that Zymosan itself is not a medical condition or disease, but rather a research reagent with potential applications in understanding human health and disease.

Complement C3 Convertase, Alternative Pathway is a complex enzyme composed of the proteins C3b and Bb. It plays a crucial role in the alternative pathway of the complement system, which is a part of the innate immune system that helps to defend the body against invading pathogens.

The alternative pathway is continuously activated at a low level, and C3 Convertase is responsible for amplifying this activation. It does so by cleaving the complement component C3 into C3a and C3b. The C3b then binds to the surface of the pathogen and can form additional C3 Convertases, leading to a positive feedback loop that results in the rapid accumulation of complement components on the surface of the pathogen.

This accumulation of complement components helps to mark the pathogen for destruction by other immune cells, such as neutrophils and macrophages. Additionally, the cleavage products C3a and C5a generated during this process can act as anaphylatoxins, inducing inflammation and attracting more immune cells to the site of infection.

Regulation of Complement C3 Convertase is critical to prevent damage to host tissues. Several regulatory proteins, such as factor H and decay-accelerating factor (DAF), help to limit the formation and activity of C3 Convertase on host cells and tissues. Dysregulation of the complement system, including the alternative pathway and Complement C3 Convertase, has been implicated in a variety of diseases, including autoimmune disorders, inflammatory diseases, and infectious diseases.

Complement C5b is a protein complex that forms during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells from the body by marking them for destruction and attracting immune cells to the site of infection or injury.

The complement component C5 is cleaved into two fragments, C5a and C5b, during the activation of the complement system. C5a is a small peptide that acts as a chemoattractant, drawing immune cells to the site of inflammation. C5b, on the other hand, forms a complex with other complement components (C6, C7, C8, and C9) to create the membrane attack complex (MAC). The MAC inserts itself into the membrane of the target cell, forming a pore that disrupts the cell's integrity and leads to its lysis or destruction.

Therefore, Complement C5b is an important protein involved in the immune response, specifically in the terminal phase of complement activation, which results in the formation of the MAC and subsequent destruction of target cells.

Complement C4a is a protein fragment or cleavage product generated during the activation of the complement system, which is a part of the immune system. The complement system helps to eliminate pathogens and damaged cells by marking them for destruction and direct lysis. Complement component 4 (C4) is one of the key proteins in this cascade, and it gets cleaved into C4a and C4b during the activation process.

C4a is a small anaphylatoxin with a molecular weight of approximately 9 kDa. It has chemotactic properties, meaning it can attract immune cells like neutrophils to the site of complement activation. Additionally, C4a can induce histamine release from mast cells and basophils, contributing to local inflammation. However, its precise physiological role in the immune response is not entirely clear, and dysregulation of C4a production has been implicated in several pathological conditions, such as autoimmune diseases and allergies.

CD55, also known as Decay-accelerating factor (DAF), is a protein that acts as an inhibitor of the complement system, which is a part of the immune system. It prevents the formation of the membrane attack complex (MAC) on host cells and tissues, thereby protecting them from damage caused by the complement activation. CD55 is found on the surface of many types of cells in the body, including red blood cells, white blood cells, and cells lining the blood vessels.

As an antigen, CD55 is a molecule that can be recognized by the immune system and stimulate an immune response. However, unlike some other antigens, CD55 does not typically elicit a strong immune response because it is a self-antigen, meaning it is normally present in the body and should not be targeted by the immune system.

In certain medical conditions, such as autoimmune disorders or transplant rejection, the immune system may mistakenly attack cells expressing CD55. In these cases, measuring the levels of CD55 antigens can provide valuable diagnostic information and help guide treatment decisions.

Phagocytosis is the process by which certain cells in the body, known as phagocytes, engulf and destroy foreign particles, bacteria, or dead cells. This mechanism plays a crucial role in the immune system's response to infection and inflammation. Phagocytes, such as neutrophils, monocytes, and macrophages, have receptors on their surface that recognize and bind to specific molecules (known as antigens) on the target particles or microorganisms.

Once attached, the phagocyte extends pseudopodia (cell extensions) around the particle, forming a vesicle called a phagosome that completely encloses it. The phagosome then fuses with a lysosome, an intracellular organelle containing digestive enzymes and other chemicals. This fusion results in the formation of a phagolysosome, where the engulfed particle is broken down by the action of these enzymes, neutralizing its harmful effects and allowing for the removal of cellular debris or pathogens.

Phagocytosis not only serves as a crucial defense mechanism against infections but also contributes to tissue homeostasis by removing dead cells and debris.

Cobra venoms are a type of snake venom that is produced by cobras, which are members of the genus Naja in the family Elapidae. These venoms are complex mixtures of proteins and other molecules that have evolved to help the snake immobilize and digest its prey.

Cobra venoms typically contain a variety of toxic components, including neurotoxins, hemotoxins, and cytotoxins. Neurotoxins target the nervous system and can cause paralysis and respiratory failure. Hemotoxins damage blood vessels and tissues, leading to internal bleeding and organ damage. Cytotoxins destroy cells and can cause tissue necrosis.

The specific composition of cobra venoms can vary widely between different species of cobras, as well as between individual snakes of the same species. Some cobras have venoms that are primarily neurotoxic, while others have venoms that are more hemotoxic or cytotoxic. The potency and effects of cobra venoms can also be influenced by factors such as the age and size of the snake, as well as the temperature and pH of the environment.

Cobra bites can be extremely dangerous and even fatal to humans, depending on the species of cobra, the amount of venom injected, and the location of the bite. Immediate medical attention is required in the event of a cobra bite, including the administration of antivenom therapy to neutralize the effects of the venom.

An antigen-antibody complex is a type of immune complex that forms when an antibody binds to a specific antigen. An antigen is any substance that triggers an immune response, while an antibody is a protein produced by the immune system to neutralize or destroy foreign substances like antigens.

When an antibody binds to an antigen, it forms a complex that can be either soluble or insoluble. Soluble complexes are formed when the antigen is small and can move freely through the bloodstream. Insoluble complexes, on the other hand, are formed when the antigen is too large to move freely, such as when it is part of a bacterium or virus.

The formation of antigen-antibody complexes plays an important role in the immune response. Once formed, these complexes can be recognized and cleared by other components of the immune system, such as phagocytes, which help to prevent further damage to the body. However, in some cases, the formation of large numbers of antigen-antibody complexes can lead to inflammation and tissue damage, contributing to the development of certain autoimmune diseases.

Immunoglobulin G (IgG) is a type of antibody, which is a protective protein produced by the immune system in response to foreign substances like bacteria or viruses. IgG is the most abundant type of antibody in human blood, making up about 75-80% of all antibodies. It is found in all body fluids and plays a crucial role in fighting infections caused by bacteria, viruses, and toxins.

IgG has several important functions:

1. Neutralization: IgG can bind to the surface of bacteria or viruses, preventing them from attaching to and infecting human cells.
2. Opsonization: IgG coats the surface of pathogens, making them more recognizable and easier for immune cells like neutrophils and macrophages to phagocytose (engulf and destroy) them.
3. Complement activation: IgG can activate the complement system, a group of proteins that work together to help eliminate pathogens from the body. Activation of the complement system leads to the formation of the membrane attack complex, which creates holes in the cell membranes of bacteria, leading to their lysis (destruction).
4. Antibody-dependent cellular cytotoxicity (ADCC): IgG can bind to immune cells like natural killer (NK) cells and trigger them to release substances that cause target cells (such as virus-infected or cancerous cells) to undergo apoptosis (programmed cell death).
5. Immune complex formation: IgG can form immune complexes with antigens, which can then be removed from the body through various mechanisms, such as phagocytosis by immune cells or excretion in urine.

IgG is a critical component of adaptive immunity and provides long-lasting protection against reinfection with many pathogens. It has four subclasses (IgG1, IgG2, IgG3, and IgG4) that differ in their structure, function, and distribution in the body.

Collectins are a group of proteins that belong to the collectin family, which are involved in the innate immune system. They are composed of a collagen-like region and a carbohydrate recognition domain (CRD), which allows them to bind to specific sugars on the surface of microorganisms, cells, and particles. Collectins play a crucial role in the defense against pathogens by promoting the clearance of microbes, modulating inflammation, and regulating immune responses.

Some examples of collectins include:

* Surfactant protein A (SP-A) and surfactant protein D (SP-D), which are found in the lungs and help to maintain the stability of the lung lining and protect against respiratory infections.
* Mannose-binding lectin (MBL), which is a serum protein that binds to mannose sugars on the surface of microorganisms, activating the complement system and promoting phagocytosis.
* Collectin liver 1 (CL-L1) and collectin kidney 1 (CL-K1), which are found in the liver and kidneys, respectively, and play a role in the clearance of apoptotic cells and immune complexes.

Deficiencies or mutations in collectins can lead to increased susceptibility to infections, autoimmune diseases, and other disorders.

Complement C1r is a protein that plays a crucial role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, C1r is one of the three proteins that make up the C1 complex, which is the first component of the classical complement pathway.

The C1 complex is composed of C1q, C1r, and C1s, and it is activated by the binding of C1q to the Fc region of an antibody that is bound to a pathogen or damaged cell. Once activated, C1r undergoes a conformational change that allows it to cleave and activate C1s. Activated C1s then goes on to cleave and activate other components of the complement system, leading to the production of the membrane attack complex (MAC), which forms a pore in the membrane of the target cell and causes lysis.

Deficiencies or mutations in the genes encoding the proteins of the C1 complex can lead to immune disorders, including hereditary angioedema, which is characterized by recurrent episodes of swelling in various parts of the body.

Complement C7 is a protein that plays a role in the complement system, which is a part of the immune system that helps to clear pathogens and damaged cells from the body. Specifically, C7 is a component of the membrane attack complex (MAC), which is a group of proteins that forms a pore in the membrane of target cells, leading to their lysis or destruction.

C7 is activated when it binds to the C5b-7 complex, which is formed by the cleavage of C5 and C6 by the C5 convertase. Once bound to the C5b-7 complex, C7 undergoes a conformational change that allows it to insert into the target cell membrane. This forms the basis for the formation of the MAC and subsequent lysis of the target cell.

Deficiencies in complement components, including C7, can lead to increased susceptibility to certain infections and autoimmune disorders. Additionally, abnormal regulation of the complement system has been implicated in a variety of diseases, including inflammatory and degenerative conditions.

Lectins are a type of proteins that bind specifically to carbohydrates and have been found in various plant and animal sources. They play important roles in biological recognition events, such as cell-cell adhesion, and can also be involved in the immune response. Some lectins can agglutinate certain types of cells or precipitate glycoproteins, while others may have a more direct effect on cellular processes. In some cases, lectins from plants can cause adverse effects in humans if ingested, such as digestive discomfort or allergic reactions.

Complement C8 is a protein component of the complement system, which is a part of the immune system that helps to eliminate pathogens and damaged cells from the body. Specifically, C8 is a part of the membrane attack complex (MAC), which forms a pore in the membrane of target cells, leading to their lysis or destruction.

C8 is composed of three subunits: alpha, beta, and gamma. It is activated when it binds to the complement component C5b67 complex on the surface of a target cell. Once activated, C8 undergoes a conformational change that allows it to insert into the target cell membrane and form a pore, which disrupts the cell's membrane integrity and can lead to its death.

Deficiencies in complement components, including C8, can make individuals more susceptible to certain infections and autoimmune diseases. Additionally, mutations in the genes encoding complement proteins have been associated with various inherited disorders, such as atypical hemolytic uremic syndrome (aHUS), which is characterized by thrombotic microangiopathy and kidney failure.

Anaphylatoxins are a group of small protein molecules that are released during an immune response, specifically as a result of the activation of the complement system. The term "anaphylatoxin" comes from their ability to induce anaphylaxis, a severe and rapid allergic reaction. There are three main anaphylatoxins, known as C3a, C4a, and C5a, which are derived from the cleavage of complement components C3, C4, and C5, respectively.

Anaphylatoxins play a crucial role in the immune response by attracting and activating various immune cells, such as neutrophils, eosinophils, and mast cells, to the site of infection or injury. They also increase vascular permeability, causing fluid to leak out of blood vessels and leading to tissue swelling. Additionally, anaphylatoxins can induce smooth muscle contraction, which can result in bronchoconstriction and hypotension.

While anaphylatoxins are important for the immune response, they can also contribute to the pathogenesis of various inflammatory diseases, such as asthma, arthritis, and sepsis. Therefore, therapies that target the complement system and anaphylatoxin production have been developed and are being investigated as potential treatments for these conditions.

CD46, also known as membrane cofactor protein (MCP), is a regulatory protein that plays a role in the immune system and helps to protect cells from complement activation. It is found on the surface of many different types of cells in the body, including cells of the immune system such as T cells and B cells, as well as cells of various other tissues such as epithelial cells and endothelial cells.

As an antigen, CD46 is a molecule that can be recognized by the immune system and stimulate an immune response. It is a type I transmembrane protein that consists of four distinct domains: two short cytoplasmic domains, a transmembrane domain, and a large extracellular domain. The extracellular domain contains several binding sites for complement proteins, which helps to regulate the activation of the complement system and prevent it from damaging host cells.

CD46 has been shown to play a role in protecting cells from complement-mediated damage, modulating immune responses, and promoting the survival and proliferation of certain types of immune cells. It is also thought to be involved in the development of some autoimmune diseases and may be a target for immunotherapy in the treatment of cancer.

CD59 is a type of protein found on the surface of many cells in the human body, including red and white blood cells, that functions as an inhibitor of the complement system. The complement system is a part of the immune system that helps to eliminate pathogens such as bacteria and viruses from the body.

CD59 specifically inhibits the formation of the membrane attack complex (MAC), which is a protein structure that forms pores in the cell membrane and can lead to cell lysis or death. By preventing the formation of the MAC, CD59 helps to protect cells from complement-mediated damage.

As an antigen, CD59 is a molecule that can be recognized by the immune system and stimulate an immune response. However, because it is a self-protein found on normal human cells, CD59 is not typically targeted by the immune system unless there is some kind of dysregulation or abnormality.

In certain medical conditions, such as autoimmune disorders or transplant rejection, the immune system may mistakenly target CD59 or other self-proteins, leading to damage to healthy cells and tissues. In these cases, treatments may be necessary to modulate or suppress the immune response and prevent further harm.

Complement receptor 3d (CR3d or CD11b/CD18) is not a medical definition in itself, but rather a specific type of integrin receptor that plays a crucial role in the immune system. Here's a breakdown of the components:

1. Complement Receptors: These are proteins found on the surface of various cells, including white blood cells (leukocytes), that recognize and bind to complement components, which are proteins involved in the immune response. The binding of complement components to their receptors helps facilitate communication between cells, enhances phagocytosis (the process by which certain cells engulf and destroy foreign particles or microorganisms), and contributes to the inflammatory response.
2. CR3 (Complement Receptor 3): Complement Receptor 3 is a heterodimeric receptor composed of two subunits, CD11b (also known as integrin alpha M) and CD18 (also known as integrin beta 2). Together, they form the integrin Mac-1 or αMβ2.
3. CR3d (CD11b/CD18): CR3d specifically refers to the CD11b subunit of the Complement Receptor 3 heterodimer. The CD11b subunit is responsible for recognizing and binding to complement component C3b, iC3b, and C4b fragments, as well as other ligands such as fibrinogen, ICAM-1 (Intercellular Adhesion Molecule 1), and factor X.

In summary, Complement Receptor 3d (CR3d or CD11b/CD18) is a type of integrin receptor found on the surface of various immune cells that recognizes and binds to complement components C3b, iC3b, and C4b fragments, as well as other ligands. This binding facilitates communication between cells, enhances phagocytosis, and contributes to the inflammatory response.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Immunoglobulin M (IgM) is a type of antibody that is primarily found in the blood and lymph fluid. It is the first antibody to be produced in response to an initial exposure to an antigen, making it an important part of the body's primary immune response. IgM antibodies are large molecules that are composed of five basic units, giving them a pentameric structure. They are primarily found on the surface of B cells as membrane-bound immunoglobulins (mlgM), where they function as receptors for antigens. Once an mlgM receptor binds to an antigen, it triggers the activation and differentiation of the B cell into a plasma cell that produces and secretes large amounts of soluble IgM antibodies.

IgM antibodies are particularly effective at agglutination (clumping) and complement activation, which makes them important in the early stages of an immune response to help clear pathogens from the bloodstream. However, they are not as stable or long-lived as other types of antibodies, such as IgG, and their levels tend to decline after the initial immune response has occurred.

In summary, Immunoglobulin M (IgM) is a type of antibody that plays a crucial role in the primary immune response to antigens by agglutination and complement activation. It is primarily found in the blood and lymph fluid, and it is produced by B cells after they are activated by an antigen.

Erythrocytes, also known as red blood cells (RBCs), are the most common type of blood cell in circulating blood in mammals. They are responsible for transporting oxygen from the lungs to the body's tissues and carbon dioxide from the tissues to the lungs.

Erythrocytes are formed in the bone marrow and have a biconcave shape, which allows them to fold and bend easily as they pass through narrow blood vessels. They do not have a nucleus or mitochondria, which makes them more flexible but also limits their ability to reproduce or repair themselves.

In humans, erythrocytes are typically disc-shaped and measure about 7 micrometers in diameter. They contain the protein hemoglobin, which binds to oxygen and gives blood its red color. The lifespan of an erythrocyte is approximately 120 days, after which it is broken down in the liver and spleen.

Abnormalities in erythrocyte count or function can lead to various medical conditions, such as anemia, polycythemia, and sickle cell disease.

I must clarify that the term "Guinea Pigs" is not typically used in medical definitions. However, in colloquial or informal language, it may refer to people who are used as the first to try out a new medical treatment or drug. This is known as being a "test subject" or "in a clinical trial."

In the field of scientific research, particularly in studies involving animals, guinea pigs are small rodents that are often used as experimental subjects due to their size, cost-effectiveness, and ease of handling. They are not actually pigs from Guinea, despite their name's origins being unclear. However, they do not exactly fit the description of being used in human medical experiments.

I apologize, but I am not able to provide a medical definition for "Egtazic Acid" because it is not a term that is recognized in the field of medicine or pharmacology. It is possible that you may have meant "Egтарic Acid," which also does not have a specific medical meaning, or "Ethylene Glycol Tetraacetic Acid (EGTA)," which is a chemical compound used in research and medicine for its ability to bind calcium ions. If you have any other questions, I would be happy to try to help answer them.

Neutrophils are a type of white blood cell that are part of the immune system's response to infection. They are produced in the bone marrow and released into the bloodstream where they circulate and are able to move quickly to sites of infection or inflammation in the body. Neutrophils are capable of engulfing and destroying bacteria, viruses, and other foreign substances through a process called phagocytosis. They are also involved in the release of inflammatory mediators, which can contribute to tissue damage in some cases. Neutrophils are characterized by the presence of granules in their cytoplasm, which contain enzymes and other proteins that help them carry out their immune functions.

Bacterial polysaccharides are complex carbohydrates that consist of long chains of sugar molecules (monosaccharides) linked together by glycosidic bonds. They are produced and used by bacteria for various purposes such as:

1. Structural components: Bacterial polysaccharides, such as peptidoglycan and lipopolysaccharide (LPS), play a crucial role in maintaining the structural integrity of bacterial cells. Peptidoglycan is a major component of the bacterial cell wall, while LPS forms the outer layer of the outer membrane in gram-negative bacteria.
2. Nutrient storage: Some bacteria synthesize and store polysaccharides as an energy reserve, similar to how plants store starch. These polysaccharides can be broken down and utilized by the bacterium when needed.
3. Virulence factors: Bacterial polysaccharides can also function as virulence factors, contributing to the pathogenesis of bacterial infections. For example, certain bacteria produce capsular polysaccharides (CPS) that surround and protect the bacterial cells from host immune defenses, allowing them to evade phagocytosis and persist within the host.
4. Adhesins: Some polysaccharides act as adhesins, facilitating the attachment of bacteria to surfaces or host cells. This is important for biofilm formation, which helps bacteria resist environmental stresses and antibiotic treatments.
5. Antigenic properties: Bacterial polysaccharides can be highly antigenic, eliciting an immune response in the host. The antigenicity of these molecules can vary between different bacterial species or even strains within a species, making them useful as targets for vaccines and diagnostic tests.

In summary, bacterial polysaccharides are complex carbohydrates that serve various functions in bacteria, including structural support, nutrient storage, virulence factor production, adhesion, and antigenicity.

I'm sorry for any confusion, but "snakes" is not a medical term. It refers to a group of legless reptiles that can be found on every continent except Antarctica. If you have any questions about snakes in a different context, please provide more information and I'll do my best to help!

Cryoglobulins are immunoglobulins (a type of antibody) that precipitate or become insoluble at reduced temperatures, typically below 37°C (98.6°F), and re-dissolve when rewarmed. They can be found in various clinical conditions such as infections, inflammatory diseases, and lymphoproliferative disorders.

The presence of cryoglobulins in the blood can lead to a variety of symptoms, including purpura (a type of skin rash), arthralgias (joint pain), neuropathy (nerve damage), and glomerulonephritis (kidney inflammation). The diagnosis of cryoglobulinemia is made by detecting the presence of cryoglobulins in the serum, which requires special handling and processing of the blood sample. Treatment of cryoglobulinemia depends on the underlying cause and may include medications such as corticosteroids, immunosuppressive agents, or targeted therapies.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

"Prevotella melaninogenica" is a gram-negative, anaerobic, rod-shaped bacterium that is commonly found as part of the normal microbiota in the oral cavity, gastrointestinal tract, and urogenital tract. It is named for its ability to produce melanin pigment. This bacterium can sometimes be associated with various infections, including dental abscesses, periodontal disease, lung infections, and bloodstream infections, particularly in individuals with compromised immune systems."

Bacterial antibodies are a type of antibodies produced by the immune system in response to an infection caused by bacteria. These antibodies are proteins that recognize and bind to specific antigens on the surface of the bacterial cells, marking them for destruction by other immune cells. Bacterial antibodies can be classified into several types based on their structure and function, including IgG, IgM, IgA, and IgE. They play a crucial role in the body's defense against bacterial infections and provide immunity to future infections with the same bacteria.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

I believe there may be some confusion in your question. "Rabbits" is a common name used to refer to the Lagomorpha species, particularly members of the family Leporidae. They are small mammals known for their long ears, strong legs, and quick reproduction.

However, if you're referring to "rabbits" in a medical context, there is a term called "rabbit syndrome," which is a rare movement disorder characterized by repetitive, involuntary movements of the fingers, resembling those of a rabbit chewing. It is also known as "finger-chewing chorea." This condition is usually associated with certain medications, particularly antipsychotics, and typically resolves when the medication is stopped or adjusted.

Streptococcus pneumoniae, also known as the pneumococcus, is a gram-positive, alpha-hemolytic bacterium frequently found in the upper respiratory tract of healthy individuals. It is a leading cause of community-acquired pneumonia and can also cause other infectious diseases such as otitis media (ear infection), sinusitis, meningitis, and bacteremia (bloodstream infection). The bacteria are encapsulated, and there are over 90 serotypes based on variations in the capsular polysaccharide. Some serotypes are more virulent or invasive than others, and the polysaccharide composition is crucial for vaccine development. S. pneumoniae infection can be treated with antibiotics, but the emergence of drug-resistant strains has become a significant global health concern.

Macular degeneration, also known as age-related macular degeneration (AMD), is a medical condition that affects the central part of the retina, called the macula. The macula is responsible for sharp, detailed vision, which is necessary for activities such as reading, driving, and recognizing faces.

In AMD, there is a breakdown or deterioration of the macula, leading to gradual loss of central vision. There are two main types of AMD: dry (atrophic) and wet (exudative). Dry AMD is more common and progresses more slowly, while wet AMD is less common but can cause rapid and severe vision loss if left untreated.

The exact causes of AMD are not fully understood, but risk factors include age, smoking, family history, high blood pressure, obesity, and exposure to sunlight. While there is no cure for AMD, treatments such as vitamin supplements, laser therapy, and medication injections can help slow its progression and reduce the risk of vision loss.

C57BL/6 (C57 Black 6) is an inbred strain of laboratory mouse that is widely used in biomedical research. The term "inbred" refers to a strain of animals where matings have been carried out between siblings or other closely related individuals for many generations, resulting in a population that is highly homozygous at most genetic loci.

The C57BL/6 strain was established in 1920 by crossing a female mouse from the dilute brown (DBA) strain with a male mouse from the black strain. The resulting offspring were then interbred for many generations to create the inbred C57BL/6 strain.

C57BL/6 mice are known for their robust health, longevity, and ease of handling, making them a popular choice for researchers. They have been used in a wide range of biomedical research areas, including studies of cancer, immunology, neuroscience, cardiovascular disease, and metabolism.

One of the most notable features of the C57BL/6 strain is its sensitivity to certain genetic modifications, such as the introduction of mutations that lead to obesity or impaired glucose tolerance. This has made it a valuable tool for studying the genetic basis of complex diseases and traits.

Overall, the C57BL/6 inbred mouse strain is an important model organism in biomedical research, providing a valuable resource for understanding the genetic and molecular mechanisms underlying human health and disease.

"Blood physiological phenomena" is a broad term that refers to various functions, processes, and characteristics related to the blood in the body. Here are some definitions of specific blood-related physiological phenomena:

1. Hematopoiesis: The process of producing blood cells in the bone marrow. This includes the production of red blood cells (erythropoiesis), white blood cells (leukopoiesis), and platelets (thrombopoiesis).
2. Hemostasis: The body's response to stop bleeding or prevent excessive blood loss after injury. It involves a complex interplay between blood vessels, platelets, and clotting factors that work together to form a clot.
3. Osmoregulation: The regulation of water and electrolyte balance in the blood. This is achieved through various mechanisms such as thirst, urine concentration, and hormonal control.
4. Acid-base balance: The maintenance of a stable pH level in the blood. This involves the balance between acidic and basic components in the blood, which can be affected by factors such as respiration, metabolism, and kidney function.
5. Hemoglobin function: The ability of hemoglobin molecules in red blood cells to bind and transport oxygen from the lungs to tissues throughout the body.
6. Blood viscosity: The thickness or flowability of blood, which can affect its ability to circulate through the body. Factors that can influence blood viscosity include hematocrit (the percentage of red blood cells in the blood), plasma proteins, and temperature.
7. Immunological function: The role of white blood cells and other components of the immune system in protecting the body against infection and disease. This includes the production of antibodies, phagocytosis (the engulfing and destruction of foreign particles), and inflammation.

Immunoelectrophoresis (IEP) is a laboratory technique used in the field of clinical pathology and immunology. It is a method for separating and identifying proteins, particularly immunoglobulins or antibodies, in a sample. This technique combines the principles of electrophoresis, which separates proteins based on their electric charge and size, with immunological reactions, which detect specific proteins using antigen-antibody interactions.

In IEP, a protein sample is first separated by electrophoresis in an agarose or agar gel matrix on a glass slide or in a test tube. After separation, an antibody specific to the protein of interest is layered on top of the gel and allowed to diffuse towards the separated proteins. This creates a reaction between the antigen (protein) and the antibody, forming a visible precipitate at the point where they meet. The precipitate line's position and intensity can then be analyzed to identify and quantify the protein of interest.

Immunoelectrophoresis is particularly useful in diagnosing various medical conditions, such as immunodeficiency disorders, monoclonal gammopathies (like multiple myeloma), and other plasma cell dyscrasias. It can help detect abnormal protein patterns, quantify specific immunoglobulins, and identify the presence of M-proteins or Bence Jones proteins, which are indicative of monoclonal gammopathies.

Edetic acid, also known as ethylenediaminetetraacetic acid (EDTA), is not a medical term per se, but a chemical compound with various applications in medicine. EDTA is a synthetic amino acid that acts as a chelating agent, which means it can bind to metallic ions and form stable complexes.

In medicine, EDTA is primarily used in the treatment of heavy metal poisoning, such as lead or mercury toxicity. It works by binding to the toxic metal ions in the body, forming a stable compound that can be excreted through urine. This helps reduce the levels of harmful metals in the body and alleviate their toxic effects.

EDTA is also used in some diagnostic tests, such as the determination of calcium levels in blood. Additionally, it has been explored as a potential therapy for conditions like atherosclerosis and Alzheimer's disease, although its efficacy in these areas remains controversial and unproven.

It is important to note that EDTA should only be administered under medical supervision due to its potential side effects and the need for careful monitoring of its use.

Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by the immune system's B cells in response to the presence of foreign substances, such as bacteria, viruses, and toxins. These Y-shaped proteins play a crucial role in identifying and neutralizing pathogens and other antigens, thereby protecting the body against infection and disease.

Immunoglobulins are composed of four polypeptide chains: two identical heavy chains and two identical light chains, held together by disulfide bonds. The variable regions of these chains form the antigen-binding sites, which recognize and bind to specific epitopes on antigens. Based on their heavy chain type, immunoglobulins are classified into five main isotypes or classes: IgA, IgD, IgE, IgG, and IgM. Each class has distinct functions in the immune response, such as providing protection in different body fluids and tissues, mediating hypersensitivity reactions, and aiding in the development of immunological memory.

In medical settings, immunoglobulins can be administered therapeutically to provide passive immunity against certain diseases or to treat immune deficiencies, autoimmune disorders, and other conditions that may benefit from immunomodulation.

Mannans are a type of complex carbohydrate, specifically a heteropolysaccharide, that are found in the cell walls of certain plants, algae, and fungi. They consist of chains of mannose sugars linked together, often with other sugar molecules such as glucose or galactose.

Mannans have various biological functions, including serving as a source of energy for microorganisms that can break them down. In some cases, mannans can also play a role in the immune response and are used as a component of vaccines to stimulate an immune response.

In the context of medicine, mannans may be relevant in certain conditions such as gut dysbiosis or allergic reactions to foods containing mannans. Additionally, some research has explored the potential use of mannans as a delivery vehicle for drugs or other therapeutic agents.

The Macrophage-1 Antigen (also known as Macrophage Antigen-1 or CD14) is a glycoprotein found on the surface of various cells, including monocytes, macrophages, and some dendritic cells. It functions as a receptor for complexes formed by lipopolysaccharides (LPS) and LPS-binding protein (LBP), which are involved in the immune response to gram-negative bacteria. CD14 plays a crucial role in activating immune cells and initiating the release of proinflammatory cytokines upon recognizing bacterial components.

In summary, Macrophage-1 Antigen is a cell surface receptor that contributes to the recognition and response against gram-negative bacteria by interacting with LPS-LBP complexes.

Antibodies are proteins produced by the immune system in response to the presence of a foreign substance, such as a bacterium or virus. They are capable of identifying and binding to specific antigens (foreign substances) on the surface of these invaders, marking them for destruction by other immune cells. Antibodies are also known as immunoglobulins and come in several different types, including IgA, IgD, IgE, IgG, and IgM, each with a unique function in the immune response. They are composed of four polypeptide chains, two heavy chains and two light chains, that are held together by disulfide bonds. The variable regions of the heavy and light chains form the antigen-binding site, which is specific to a particular antigen.

Serum Amyloid P-component (SAP) is a protein that is normally present in the blood and other bodily fluids. It is a part of the larger family of pentraxin proteins, which are involved in the innate immune response, meaning they provide immediate defense against foreign invaders without needing to adapt over time. SAP plays a role in inflammation, immune complex clearance, and complement activation.

In the context of amyloidosis, SAP binds to misfolded proteins called amyloid fibrils, which can deposit in various tissues and organs, leading to their dysfunction and failure. The accumulation of these amyloid fibrils with SAP is a hallmark of systemic amyloidosis.

It's important to note that while SAP plays a role in the pathogenesis of amyloidosis, it is not directly responsible for causing the disease. Instead, its presence can serve as a useful marker for diagnosing and monitoring the progression of amyloidosis.

A "knockout" mouse is a genetically engineered mouse in which one or more genes have been deleted or "knocked out" using molecular biology techniques. This allows researchers to study the function of specific genes and their role in various biological processes, as well as potential associations with human diseases. The mice are generated by introducing targeted DNA modifications into embryonic stem cells, which are then used to create a live animal. Knockout mice have been widely used in biomedical research to investigate gene function, disease mechanisms, and potential therapeutic targets.

Mannose-binding lectins (MBLs) are a group of proteins that belong to the collectin family and play a crucial role in the innate immune system. They are primarily produced by the liver and secreted into the bloodstream. MBLs have a specific affinity for mannose sugar residues found on the surface of various microorganisms, including bacteria, viruses, fungi, and parasites.

The primary function of MBLs is to recognize and bind to these mannose-rich structures, which triggers the complement system's activation through the lectin pathway. This process leads to the destruction of the microorganism by opsonization (coating the microbe to enhance phagocytosis) or direct lysis. MBLs also have the ability to neutralize certain viruses and inhibit the replication of others, further contributing to their antimicrobial activity.

Deficiencies in MBL levels or function have been associated with an increased susceptibility to infections, particularly in children and older adults. However, the clinical significance of MBL deficiency remains a subject of ongoing research.

Serum, in the context of clinical and medical laboratory science, refers to the fluid that is obtained after blood coagulation. It is the yellowish, straw-colored liquid fraction of whole blood that remains after the clotting factors have been removed. Serum contains various proteins, electrolytes, hormones, antibodies, antigens, and other substances, which can be analyzed to help diagnose and monitor a wide range of medical conditions. It is commonly used for various clinical tests such as chemistry panels, immunological assays, drug screening, and infectious disease testing.

Monoclonal antibodies are a type of antibody that are identical because they are produced by a single clone of cells. They are laboratory-produced molecules that act like human antibodies in the immune system. They can be designed to attach to specific proteins found on the surface of cancer cells, making them useful for targeting and treating cancer. Monoclonal antibodies can also be used as a therapy for other diseases, such as autoimmune disorders and inflammatory conditions.

Monoclonal antibodies are produced by fusing a single type of immune cell, called a B cell, with a tumor cell to create a hybrid cell, or hybridoma. This hybrid cell is then able to replicate indefinitely, producing a large number of identical copies of the original antibody. These antibodies can be further modified and engineered to enhance their ability to bind to specific targets, increase their stability, and improve their effectiveness as therapeutic agents.

Monoclonal antibodies have several mechanisms of action in cancer therapy. They can directly kill cancer cells by binding to them and triggering an immune response. They can also block the signals that promote cancer growth and survival. Additionally, monoclonal antibodies can be used to deliver drugs or radiation directly to cancer cells, increasing the effectiveness of these treatments while minimizing their side effects on healthy tissues.

Monoclonal antibodies have become an important tool in modern medicine, with several approved for use in cancer therapy and other diseases. They are continuing to be studied and developed as a promising approach to treating a wide range of medical conditions.

Sialic acids are a family of nine-carbon sugars that are commonly found on the outermost surface of many cell types, particularly on the glycoconjugates of mucins in various secretions and on the glycoproteins and glycolipids of cell membranes. They play important roles in a variety of biological processes, including cell recognition, immune response, and viral and bacterial infectivity. Sialic acids can exist in different forms, with N-acetylneuraminic acid being the most common one in humans.

Membranoproliferative Glomerulonephritis (MPGN) is a type of glomerulonephritis, which is a group of kidney disorders characterized by inflammation and damage to the glomeruli, the tiny blood vessels in the kidneys responsible for filtering waste and excess fluids from the blood.

MPGN is specifically characterized by thickening of the glomerular basement membrane and proliferation (increased number) of cells in the mesangium, a region within the glomerulus. This condition can be primary or secondary to other diseases such as infections, autoimmune disorders, or monoclonal gammopathies.

MPGN is typically classified into three types based on the pattern of injury seen on electron microscopy: Type I, Type II (Dense Deposit Disease), and Type III. Each type has distinct clinical features, laboratory findings, and treatment approaches. Symptoms of MPGN may include hematuria (blood in urine), proteinuria (protein in urine), hypertension (high blood pressure), edema (swelling), and eventually progress to chronic kidney disease or end-stage renal disease if left untreated.

I apologize, but "sheep" is not a term that has a medical definition. It is a common animal with the scientific name Ovis aries. If you have any medical or health-related questions, I would be happy to try and help answer those for you.

Glomerulonephritis is a medical condition that involves inflammation of the glomeruli, which are the tiny blood vessel clusters in the kidneys that filter waste and excess fluids from the blood. This inflammation can impair the kidney's ability to filter blood properly, leading to symptoms such as proteinuria (protein in the urine), hematuria (blood in the urine), edema (swelling), hypertension (high blood pressure), and eventually kidney failure.

Glomerulonephritis can be acute or chronic, and it may occur as a primary kidney disease or secondary to other medical conditions such as infections, autoimmune disorders, or vasculitis. The diagnosis of glomerulonephritis typically involves a combination of medical history, physical examination, urinalysis, blood tests, and imaging studies, with confirmation often requiring a kidney biopsy. Treatment depends on the underlying cause and severity of the disease but may include medications to suppress inflammation, control blood pressure, and manage symptoms.

Glycoproteins are complex proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbone. These glycans are linked to the protein through asparagine residues (N-linked) or serine/threonine residues (O-linked). Glycoproteins play crucial roles in various biological processes, including cell recognition, cell-cell interactions, cell adhesion, and signal transduction. They are widely distributed in nature and can be found on the outer surface of cell membranes, in extracellular fluids, and as components of the extracellular matrix. The structure and composition of glycoproteins can vary significantly depending on their function and location within an organism.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Blood proteins, also known as serum proteins, are a group of complex molecules present in the blood that are essential for various physiological functions. These proteins include albumin, globulins (alpha, beta, and gamma), and fibrinogen. They play crucial roles in maintaining oncotic pressure, transporting hormones, enzymes, vitamins, and minerals, providing immune defense, and contributing to blood clotting.

Albumin is the most abundant protein in the blood, accounting for about 60% of the total protein mass. It functions as a transporter of various substances, such as hormones, fatty acids, and drugs, and helps maintain oncotic pressure, which is essential for fluid balance between the blood vessels and surrounding tissues.

Globulins are divided into three main categories: alpha, beta, and gamma globulins. Alpha and beta globulins consist of transport proteins like lipoproteins, hormone-binding proteins, and enzymes. Gamma globulins, also known as immunoglobulins or antibodies, are essential for the immune system's defense against pathogens.

Fibrinogen is a protein involved in blood clotting. When an injury occurs, fibrinogen is converted into fibrin, which forms a mesh to trap platelets and form a clot, preventing excessive bleeding.

Abnormal levels of these proteins can indicate various medical conditions, such as liver or kidney disease, malnutrition, infections, inflammation, or autoimmune disorders. Blood protein levels are typically measured through laboratory tests like serum protein electrophoresis (SPE) and immunoelectrophoresis (IEP).

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

A dose-response relationship in immunology refers to the quantitative relationship between the dose or amount of an antigen (a substance that triggers an immune response) and the magnitude or strength of the resulting immune response. Generally, as the dose of an antigen increases, the intensity and/or duration of the immune response also increase, up to a certain point. This relationship helps in determining the optimal dosage for vaccines and immunotherapies, ensuring sufficient immune activation while minimizing potential adverse effects.

Innate immunity, also known as non-specific immunity or natural immunity, is the inherent defense mechanism that provides immediate protection against potentially harmful pathogens (like bacteria, viruses, fungi, and parasites) without the need for prior exposure. This type of immunity is present from birth and does not adapt to specific threats over time.

Innate immune responses involve various mechanisms such as:

1. Physical barriers: Skin and mucous membranes prevent pathogens from entering the body.
2. Chemical barriers: Enzymes, stomach acid, and lysozyme in tears, saliva, and sweat help to destroy or inhibit the growth of microorganisms.
3. Cellular responses: Phagocytic cells (neutrophils, monocytes, macrophages) recognize and engulf foreign particles and pathogens, while natural killer (NK) cells target and eliminate virus-infected or cancerous cells.
4. Inflammatory response: When an infection occurs, the innate immune system triggers inflammation to increase blood flow, recruit immune cells, and remove damaged tissue.
5. Complement system: A group of proteins that work together to recognize and destroy pathogens directly or enhance phagocytosis by coating them with complement components (opsonization).

Innate immunity plays a crucial role in initiating the adaptive immune response, which is specific to particular pathogens and provides long-term protection through memory cells. Both innate and adaptive immunity work together to maintain overall immune homeostasis and protect the body from infections and diseases.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

The Fluorescent Antibody Technique (FAT) is a type of immunofluorescence assay used in laboratory medicine and pathology for the detection and localization of specific antigens or antibodies in tissues, cells, or microorganisms. In this technique, a fluorescein-labeled antibody is used to selectively bind to the target antigen or antibody, forming an immune complex. When excited by light of a specific wavelength, the fluorescein label emits light at a longer wavelength, typically visualized as green fluorescence under a fluorescence microscope.

The FAT is widely used in diagnostic microbiology for the identification and characterization of various bacteria, viruses, fungi, and parasites. It has also been applied in the diagnosis of autoimmune diseases and certain cancers by detecting specific antibodies or antigens in patient samples. The main advantage of FAT is its high sensitivity and specificity, allowing for accurate detection and differentiation of various pathogens and disease markers. However, it requires specialized equipment and trained personnel to perform and interpret the results.

The Complement C1 Inhibitor protein, also known as C1-INH, is a protein involved in the regulation of the complement system and the contact system, which are parts of the immune system. The complement system helps to eliminate pathogens (e.g., bacteria, viruses) from the body, while the contact system helps to regulate blood coagulation and inflammation.

C1-INH works by inhibiting the activation of C1, an enzyme complex that is the first component of the classical complement pathway. By inhibiting C1, C1-INH prevents the activation of downstream components of the complement system, thereby helping to regulate the immune response and prevent excessive inflammation.

Deficiencies or dysfunction in the C1-INH protein can lead to a group of genetic disorders known as C1 inhibitor deficiency disorders, which include hereditary angioedema (HAE) and acquired angioedema (AAE). These conditions are characterized by recurrent episodes of swelling in various parts of the body, such as the face, hands, feet, and airway, which can be painful and potentially life-threatening if they affect the airway.

An Enzyme-Linked Immunosorbent Assay (ELISA) is a type of analytical biochemistry assay used to detect and quantify the presence of a substance, typically a protein or peptide, in a liquid sample. It takes its name from the enzyme-linked antibodies used in the assay.

In an ELISA, the sample is added to a well containing a surface that has been treated to capture the target substance. If the target substance is present in the sample, it will bind to the surface. Next, an enzyme-linked antibody specific to the target substance is added. This antibody will bind to the captured target substance if it is present. After washing away any unbound material, a substrate for the enzyme is added. If the enzyme is present due to its linkage to the antibody, it will catalyze a reaction that produces a detectable signal, such as a color change or fluorescence. The intensity of this signal is proportional to the amount of target substance present in the sample, allowing for quantification.

ELISAs are widely used in research and clinical settings to detect and measure various substances, including hormones, viruses, and bacteria. They offer high sensitivity, specificity, and reproducibility, making them a reliable choice for many applications.

Bacterial antigens are substances found on the surface or produced by bacteria that can stimulate an immune response in a host organism. These antigens can be proteins, polysaccharides, teichoic acids, lipopolysaccharides, or other molecules that are recognized as foreign by the host's immune system.

When a bacterial antigen is encountered by the host's immune system, it triggers a series of responses aimed at eliminating the bacteria and preventing infection. The host's immune system recognizes the antigen as foreign through the use of specialized receptors called pattern recognition receptors (PRRs), which are found on various immune cells such as macrophages, dendritic cells, and neutrophils.

Once a bacterial antigen is recognized by the host's immune system, it can stimulate both the innate and adaptive immune responses. The innate immune response involves the activation of inflammatory pathways, the recruitment of immune cells to the site of infection, and the production of antimicrobial peptides.

The adaptive immune response, on the other hand, involves the activation of T cells and B cells, which are specific to the bacterial antigen. These cells can recognize and remember the antigen, allowing for a more rapid and effective response upon subsequent exposures.

Bacterial antigens are important in the development of vaccines, as they can be used to stimulate an immune response without causing disease. By identifying specific bacterial antigens that are associated with virulence or pathogenicity, researchers can develop vaccines that target these antigens and provide protection against infection.

'Cryptococcus' is a genus of encapsulated, budding yeast that are found in the environment, particularly in soil and bird droppings. The most common species that causes infection in humans is Cryptococcus neoformans, followed by Cryptococcus gattii.

Infection with Cryptococcus can occur when a person inhales the microscopic yeast cells, which can then lead to lung infections (pneumonia) or disseminated disease, particularly in people with weakened immune systems. The most common form of disseminated cryptococcal infection is meningitis, an inflammation of the membranes surrounding the brain and spinal cord.

Cryptococcal infections can be serious and even life-threatening, especially in individuals with HIV/AIDS or other conditions that weaken the immune system. Treatment typically involves antifungal medications, such as amphotericin B and fluconazole.

Venom is a complex mixture of toxic compounds produced by certain animals, such as snakes, spiders, scorpions, and marine creatures like cone snails and stonefish. These toxic substances are specifically designed to cause damage to the tissues or interfere with the normal physiological processes of other organisms, which can lead to harmful or even lethal effects.

Venoms typically contain a variety of components, including enzymes, peptides, proteins, and small molecules, each with specific functions that contribute to the overall toxicity of the mixture. Some of these components may cause localized damage, such as tissue necrosis or inflammation, while others can have systemic effects, impacting various organs and bodily functions.

The study of venoms, known as toxinology, has important implications for understanding the evolution of animal behavior, developing new therapeutics, and advancing medical treatments for envenomation (the process of being poisoned by venom). Additionally, venoms have been used in traditional medicine for centuries, and ongoing research continues to uncover novel compounds with potential applications in modern pharmacology.

Species specificity is a term used in the field of biology, including medicine, to refer to the characteristic of a biological entity (such as a virus, bacterium, or other microorganism) that allows it to interact exclusively or preferentially with a particular species. This means that the biological entity has a strong affinity for, or is only able to infect, a specific host species.

For example, HIV is specifically adapted to infect human cells and does not typically infect other animal species. Similarly, some bacterial toxins are species-specific and can only affect certain types of animals or humans. This concept is important in understanding the transmission dynamics and host range of various pathogens, as well as in developing targeted therapies and vaccines.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Blood is the fluid that circulates in the body of living organisms, carrying oxygen and nutrients to the cells and removing carbon dioxide and other waste products. It is composed of red and white blood cells suspended in a liquid called plasma. The main function of blood is to transport oxygen from the lungs to the body's tissues and carbon dioxide from the tissues to the lungs. It also transports nutrients, hormones, and other substances to the cells and removes waste products from them. Additionally, blood plays a crucial role in the body's immune system by helping to fight infection and disease.

Lipopolysaccharides (LPS) are large molecules found in the outer membrane of Gram-negative bacteria. They consist of a hydrophilic polysaccharide called the O-antigen, a core oligosaccharide, and a lipid portion known as Lipid A. The Lipid A component is responsible for the endotoxic activity of LPS, which can trigger a powerful immune response in animals, including humans. This response can lead to symptoms such as fever, inflammation, and septic shock, especially when large amounts of LPS are introduced into the bloodstream.

Antibody specificity refers to the ability of an antibody to bind to a specific epitope or antigenic determinant on an antigen. Each antibody has a unique structure that allows it to recognize and bind to a specific region of an antigen, typically a small portion of the antigen's surface made up of amino acids or sugar residues. This highly specific binding is mediated by the variable regions of the antibody's heavy and light chains, which form a pocket that recognizes and binds to the epitope.

The specificity of an antibody is determined by its unique complementarity-determining regions (CDRs), which are loops of amino acids located in the variable domains of both the heavy and light chains. The CDRs form a binding site that recognizes and interacts with the epitope on the antigen. The precise fit between the antibody's binding site and the epitope is critical for specificity, as even small changes in the structure of either can prevent binding.

Antibody specificity is important in immune responses because it allows the immune system to distinguish between self and non-self antigens. This helps to prevent autoimmune reactions where the immune system attacks the body's own cells and tissues. Antibody specificity also plays a crucial role in diagnostic tests, such as ELISA assays, where antibodies are used to detect the presence of specific antigens in biological samples.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

Magnesium is an essential mineral that plays a crucial role in various biological processes in the human body. It is the fourth most abundant cation in the body and is involved in over 300 enzymatic reactions, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. Magnesium also contributes to the structural development of bones and teeth.

In medical terms, magnesium deficiency can lead to several health issues, such as muscle cramps, weakness, heart arrhythmias, and seizures. On the other hand, excessive magnesium levels can cause symptoms like diarrhea, nausea, and muscle weakness. Magnesium supplements or magnesium-rich foods are often recommended to maintain optimal magnesium levels in the body.

Some common dietary sources of magnesium include leafy green vegetables, nuts, seeds, legumes, whole grains, and dairy products. Magnesium is also available in various forms as a dietary supplement, including magnesium oxide, magnesium citrate, magnesium chloride, and magnesium glycinate.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

'Immune sera' refers to the serum fraction of blood that contains antibodies produced in response to an antigenic stimulus, such as a vaccine or an infection. These antibodies are proteins known as immunoglobulins, which are secreted by B cells (a type of white blood cell) and can recognize and bind to specific antigens. Immune sera can be collected from an immunized individual and used as a source of passive immunity to protect against infection or disease. It is often used in research and diagnostic settings to identify or measure the presence of specific antigens or antibodies.

Animal disease models are specialized animals, typically rodents such as mice or rats, that have been genetically engineered or exposed to certain conditions to develop symptoms and physiological changes similar to those seen in human diseases. These models are used in medical research to study the pathophysiology of diseases, identify potential therapeutic targets, test drug efficacy and safety, and understand disease mechanisms.

The genetic modifications can include knockout or knock-in mutations, transgenic expression of specific genes, or RNA interference techniques. The animals may also be exposed to environmental factors such as chemicals, radiation, or infectious agents to induce the disease state.

Examples of animal disease models include:

1. Mouse models of cancer: Genetically engineered mice that develop various types of tumors, allowing researchers to study cancer initiation, progression, and metastasis.
2. Alzheimer's disease models: Transgenic mice expressing mutant human genes associated with Alzheimer's disease, which exhibit amyloid plaque formation and cognitive decline.
3. Diabetes models: Obese and diabetic mouse strains like the NOD (non-obese diabetic) or db/db mice, used to study the development of type 1 and type 2 diabetes, respectively.
4. Cardiovascular disease models: Atherosclerosis-prone mice, such as ApoE-deficient or LDLR-deficient mice, that develop plaque buildup in their arteries when fed a high-fat diet.
5. Inflammatory bowel disease models: Mice with genetic mutations affecting intestinal barrier function and immune response, such as IL-10 knockout or SAMP1/YitFc mice, which develop colitis.

Animal disease models are essential tools in preclinical research, but it is important to recognize their limitations. Differences between species can affect the translatability of results from animal studies to human patients. Therefore, researchers must carefully consider the choice of model and interpret findings cautiously when applying them to human diseases.

'Cryptococcus neoformans' is a species of encapsulated, budding yeast that is an important cause of fungal infections in humans and animals. The capsule surrounding the cell wall is composed of polysaccharides and is a key virulence factor, allowing the organism to evade host immune responses. C. neoformans is found worldwide in soil, particularly in association with bird droppings, and can be inhaled, leading to pulmonary infection. In people with weakened immune systems, such as those with HIV/AIDS, hematological malignancies, or organ transplants, C. neoformans can disseminate from the lungs to other sites, most commonly the central nervous system (CNS), causing meningitis. The infection can also affect other organs, including the skin, bones, and eyes.

The diagnosis of cryptococcosis typically involves microscopic examination and culture of clinical specimens, such as sputum, blood, or cerebrospinal fluid (CSF), followed by biochemical and molecular identification of the organism. Treatment usually consists of a combination of antifungal medications, such as amphotericin B and fluconazole, along with management of any underlying immunodeficiency. The prognosis of cryptococcosis depends on various factors, including the patient's immune status, the extent and severity of infection, and the timeliness and adequacy of treatment.

Bacteroides are a genus of gram-negative, anaerobic, rod-shaped bacteria that are normally present in the human gastrointestinal tract. They are part of the normal gut microbiota and play an important role in breaking down complex carbohydrates and other substances in the gut. However, some species of Bacteroides can cause opportunistic infections, particularly in individuals with weakened immune systems or when they spread to other parts of the body. They are resistant to many commonly used antibiotics, making infections caused by these bacteria difficult to treat.

Immunodiffusion is a laboratory technique used in immunology to detect and measure the presence of specific antibodies or antigens in a sample. It is based on the principle of diffusion, where molecules move from an area of high concentration to an area of low concentration until they reach equilibrium. In this technique, a sample containing an unknown quantity of antigen or antibody is placed in a gel or agar medium that contains a known quantity of antibody or antigen, respectively.

The two substances then diffuse towards each other and form a visible precipitate at the point where they meet and reach equivalence, which indicates the presence and quantity of the specific antigen or antibody in the sample. There are several types of immunodiffusion techniques, including radial immunodiffusion (RID) and double immunodiffusion (Ouchterlony technique). These techniques are widely used in diagnostic laboratories to identify and measure various antigens and antibodies, such as those found in infectious diseases, autoimmune disorders, and allergic reactions.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

Electrophoresis, polyacrylamide gel (EPG) is a laboratory technique used to separate and analyze complex mixtures of proteins or nucleic acids (DNA or RNA) based on their size and electrical charge. This technique utilizes a matrix made of cross-linked polyacrylamide, a type of gel, which provides a stable and uniform environment for the separation of molecules.

In this process:

1. The polyacrylamide gel is prepared by mixing acrylamide monomers with a cross-linking agent (bis-acrylamide) and a catalyst (ammonium persulfate) in the presence of a buffer solution.
2. The gel is then poured into a mold and allowed to polymerize, forming a solid matrix with uniform pore sizes that depend on the concentration of acrylamide used. Higher concentrations result in smaller pores, providing better resolution for separating smaller molecules.
3. Once the gel has set, it is placed in an electrophoresis apparatus containing a buffer solution. Samples containing the mixture of proteins or nucleic acids are loaded into wells on the top of the gel.
4. An electric field is applied across the gel, causing the negatively charged molecules to migrate towards the positive electrode (anode) while positively charged molecules move toward the negative electrode (cathode). The rate of migration depends on the size, charge, and shape of the molecules.
5. Smaller molecules move faster through the gel matrix and will migrate farther from the origin compared to larger molecules, resulting in separation based on size. Proteins and nucleic acids can be selectively stained after electrophoresis to visualize the separated bands.

EPG is widely used in various research fields, including molecular biology, genetics, proteomics, and forensic science, for applications such as protein characterization, DNA fragment analysis, cloning, mutation detection, and quality control of nucleic acid or protein samples.

A genetic complementation test is a laboratory procedure used in molecular genetics to determine whether two mutated genes can complement each other's function, indicating that they are located at different loci and represent separate alleles. This test involves introducing a normal or wild-type copy of one gene into a cell containing a mutant version of the same gene, and then observing whether the presence of the normal gene restores the normal function of the mutated gene. If the introduction of the normal gene results in the restoration of the normal phenotype, it suggests that the two genes are located at different loci and can complement each other's function. However, if the introduction of the normal gene does not restore the normal phenotype, it suggests that the two genes are located at the same locus and represent different alleles of the same gene. This test is commonly used to map genes and identify genetic interactions in a variety of organisms, including bacteria, yeast, and animals.

Mannose is a simple sugar (monosaccharide) that is similar in structure to glucose. It is a hexose, meaning it contains six carbon atoms. Mannose is a stereoisomer of glucose, meaning it has the same chemical formula but a different structural arrangement of its atoms.

Mannose is not as commonly found in foods as other simple sugars, but it can be found in some fruits, such as cranberries, blueberries, and peaches, as well as in certain vegetables, like sweet potatoes and turnips. It is also found in some dietary fibers, such as those found in beans and whole grains.

In the body, mannose can be metabolized and used for energy, but it is also an important component of various glycoproteins and glycolipids, which are molecules that play critical roles in many biological processes, including cell recognition, signaling, and adhesion.

Mannose has been studied as a potential therapeutic agent for various medical conditions, including urinary tract infections (UTIs), because it can inhibit the attachment of certain bacteria to the cells lining the urinary tract. Additionally, mannose-binding lectins have been investigated for their potential role in the immune response to viral and bacterial infections.

Exons are the coding regions of DNA that remain in the mature, processed mRNA after the removal of non-coding intronic sequences during RNA splicing. These exons contain the information necessary to encode proteins, as they specify the sequence of amino acids within a polypeptide chain. The arrangement and order of exons can vary between different genes and even between different versions of the same gene (alternative splicing), allowing for the generation of multiple protein isoforms from a single gene. This complexity in exon structure and usage significantly contributes to the diversity and functionality of the proteome.

Surface Plasmon Resonance (SPR) is a physical phenomenon that occurs at the interface between a metal and a dielectric material, when electromagnetic radiation (usually light) is shone on it. It involves the collective oscillation of free electrons in the metal, known as surface plasmons, which are excited by the incident light. The resonance condition is met when the momentum and energy of the photons match those of the surface plasmons, leading to a strong absorption of light and an evanescent wave that extends into the dielectric material.

In the context of medical diagnostics and research, SPR is often used as a sensitive and label-free detection technique for biomolecular interactions. By immobilizing one binding partner (e.g., a receptor or antibody) onto the metal surface and flowing the other partner (e.g., a ligand or antigen) over it, changes in the refractive index at the interface can be measured in real-time as the plasmons are disturbed by the presence of bound molecules. This allows for the quantification of binding affinities, kinetics, and specificity with high sensitivity and selectivity.

A binding site on an antibody refers to the specific region on the surface of the antibody molecule that can recognize and bind to a specific antigen. Antibodies are proteins produced by the immune system in response to the presence of foreign substances called antigens. They have two main functions: to neutralize the harmful effects of antigens and to help eliminate them from the body.

The binding site of an antibody is located at the tips of its Y-shaped structure, formed by the variable regions of the heavy and light chains of the antibody molecule. These regions contain unique amino acid sequences that determine the specificity of the antibody for a particular antigen. The binding site can recognize and bind to a specific epitope or region on the antigen, forming an antigen-antibody complex.

The binding between the antibody and antigen is highly specific and depends on non-covalent interactions such as hydrogen bonds, van der Waals forces, and electrostatic attractions. This interaction plays a crucial role in the immune response, as it allows the immune system to recognize and eliminate pathogens and other foreign substances from the body.

Enzyme precursors are typically referred to as zymogens or proenzymes. These are inactive forms of enzymes that can be activated under specific conditions. When the need for the enzyme's function arises, the proenzyme is converted into its active form through a process called proteolysis, where it is cleaved by another enzyme. This mechanism helps control and regulate the activation of certain enzymes in the body, preventing unwanted or premature reactions. A well-known example of an enzyme precursor is trypsinogen, which is converted into its active form, trypsin, in the digestive system.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

The term "Receptor, Anaphylatoxin C5a" refers to a specific type of receptor found on the surface of various cells in the human body, including immune cells and endothelial cells. This receptor binds to a molecule called C5a, which is a cleavage product of the complement component C5 and is one of the most potent anaphylatoxins.

Anaphylatoxins are inflammatory mediators that play a crucial role in the immune response, particularly in the activation of the complement system and the recruitment of immune cells to sites of infection or injury. C5a is generated during the activation of the complement system and has a wide range of biological activities, including chemotaxis (attracting immune cells to the site of inflammation), increased vascular permeability, and the activation of immune cells such as neutrophils, monocytes, and mast cells.

The C5a receptor, also known as CD88, is a G protein-coupled receptor that belongs to the superfamily of seven transmembrane domain receptors. When C5a binds to the receptor, it triggers a series of intracellular signaling events that lead to the activation of various cellular responses, such as the release of inflammatory mediators and the recruitment of immune cells to the site of inflammation.

Abnormal activation of the C5a/C5a receptor pathway has been implicated in a variety of inflammatory diseases, including sepsis, acute respiratory distress syndrome (ARDS), and autoimmune disorders. Therefore, targeting this pathway with therapeutic agents has emerged as a promising strategy for the treatment of these conditions.

Macrophages are a type of white blood cell that are an essential part of the immune system. They are large, specialized cells that engulf and destroy foreign substances, such as bacteria, viruses, parasites, and fungi, as well as damaged or dead cells. Macrophages are found throughout the body, including in the bloodstream, lymph nodes, spleen, liver, lungs, and connective tissues. They play a critical role in inflammation, immune response, and tissue repair and remodeling.

Macrophages originate from monocytes, which are a type of white blood cell produced in the bone marrow. When monocytes enter the tissues, they differentiate into macrophages, which have a larger size and more specialized functions than monocytes. Macrophages can change their shape and move through tissues to reach sites of infection or injury. They also produce cytokines, chemokines, and other signaling molecules that help coordinate the immune response and recruit other immune cells to the site of infection or injury.

Macrophages have a variety of surface receptors that allow them to recognize and respond to different types of foreign substances and signals from other cells. They can engulf and digest foreign particles, bacteria, and viruses through a process called phagocytosis. Macrophages also play a role in presenting antigens to T cells, which are another type of immune cell that helps coordinate the immune response.

Overall, macrophages are crucial for maintaining tissue homeostasis, defending against infection, and promoting wound healing and tissue repair. Dysregulation of macrophage function has been implicated in a variety of diseases, including cancer, autoimmune disorders, and chronic inflammatory conditions.

BALB/c is an inbred strain of laboratory mouse that is widely used in biomedical research. The strain was developed at the Institute of Cancer Research in London by Henry Baldwin and his colleagues in the 1920s, and it has since become one of the most commonly used inbred strains in the world.

BALB/c mice are characterized by their black coat color, which is determined by a recessive allele at the tyrosinase locus. They are also known for their docile and friendly temperament, making them easy to handle and work with in the laboratory.

One of the key features of BALB/c mice that makes them useful for research is their susceptibility to certain types of tumors and immune responses. For example, they are highly susceptible to developing mammary tumors, which can be induced by chemical carcinogens or viral infection. They also have a strong Th2-biased immune response, which makes them useful models for studying allergic diseases and asthma.

BALB/c mice are also commonly used in studies of genetics, neuroscience, behavior, and infectious diseases. Because they are an inbred strain, they have a uniform genetic background, which makes it easier to control for genetic factors in experiments. Additionally, because they have been bred in the laboratory for many generations, they are highly standardized and reproducible, making them ideal subjects for scientific research.

Animal testing alternatives, also known as alternative methods or replacement methods, refer to scientific techniques that can be used to replace the use of animals in research and testing. These methods aim to achieve the same scientific objectives while avoiding harm to animals. There are several categories of animal testing alternatives:

1. In vitro (test tube or cell culture) methods: These methods involve growing cells or tissues in a laboratory setting, outside of a living organism. They can be used to study the effects of chemicals, drugs, and other substances on specific cell types or tissues.
2. Computer modeling and simulation: Advanced computer programs and algorithms can be used to model biological systems and predict how they will respond to various stimuli. These methods can help researchers understand complex biological processes without using animals.
3. In silico (using computer models) methods: These methods involve the use of computational tools and databases to predict the potential toxicity or other biological effects of chemicals, drugs, and other substances. They can be used to identify potential hazards and prioritize further testing.
4. Microdosing: This method involves giving human volunteers very small doses of a drug or chemical, followed by careful monitoring to assess its safety and pharmacological properties. This approach can provide valuable information while minimizing the use of animals.
5. Tissue engineering: Scientists can create functional tissue constructs using cells, scaffolds, and bioreactors. These engineered tissues can be used to study the effects of drugs, chemicals, and other substances on human tissues without using animals.
6. Human-based approaches: These methods involve the use of human volunteers, donated tissues, or cells obtained from consenting adults. Examples include microdosing, organ-on-a-chip technology, and the use of human cell lines in laboratory experiments.

These animal testing alternatives can help reduce the number of animals used in research and testing, refine experimental procedures to minimize suffering, and replace the use of animals with non-animal methods whenever possible.

A peptide fragment is a short chain of amino acids that is derived from a larger peptide or protein through various biological or chemical processes. These fragments can result from the natural breakdown of proteins in the body during regular physiological processes, such as digestion, or they can be produced experimentally in a laboratory setting for research or therapeutic purposes.

Peptide fragments are often used in research to map the structure and function of larger peptides and proteins, as well as to study their interactions with other molecules. In some cases, peptide fragments may also have biological activity of their own and can be developed into drugs or diagnostic tools. For example, certain peptide fragments derived from hormones or neurotransmitters may bind to receptors in the body and mimic or block the effects of the full-length molecule.

The retinal pigment epithelium (RPE) is a single layer of cells located between the photoreceptor cells of the retina and the choroid, which is a part of the eye containing blood vessels. The RPE plays a crucial role in maintaining the health and function of the photoreceptors by providing them with nutrients, removing waste products, and helping to regulate the light-sensitive visual pigments within the photoreceptors.

The RPE cells contain pigment granules that absorb excess light to prevent scattering within the eye and improve visual acuity. They also help to form the blood-retina barrier, which restricts the movement of certain molecules between the retina and the choroid, providing an important protective function for the retina.

Damage to the RPE can lead to a variety of eye conditions, including age-related macular degeneration (AMD), which is a leading cause of vision loss in older adults.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

An antigen-antibody reaction is a specific immune response that occurs when an antigen (a foreign substance, such as a protein or polysaccharide on the surface of a bacterium or virus) comes into contact with a corresponding antibody (a protective protein produced by the immune system in response to the antigen). The antigen and antibody bind together, forming an antigen-antibody complex. This interaction can neutralize the harmful effects of the antigen, mark it for destruction by other immune cells, or activate complement proteins to help eliminate the antigen from the body. Antigen-antibody reactions are a crucial part of the adaptive immune response and play a key role in the body's defense against infection and disease.

Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease that can affect almost any organ or system in the body. In SLE, the immune system produces an exaggerated response, leading to the production of autoantibodies that attack the body's own cells and tissues, causing inflammation and damage. The symptoms and severity of SLE can vary widely from person to person, but common features include fatigue, joint pain, skin rashes (particularly a "butterfly" rash across the nose and cheeks), fever, hair loss, and sensitivity to sunlight.

Systemic lupus erythematosus can also affect the kidneys, heart, lungs, brain, blood vessels, and other organs, leading to a wide range of symptoms such as kidney dysfunction, chest pain, shortness of breath, seizures, and anemia. The exact cause of SLE is not fully understood, but it is believed to involve a combination of genetic, environmental, and hormonal factors. Treatment typically involves medications to suppress the immune system and manage symptoms, and may require long-term management by a team of healthcare professionals.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Neisseria meningitidis is a Gram-negative, aerobic, bean-shaped diplococcus bacterium. It is one of the leading causes of bacterial meningitis and sepsis (known as meningococcal disease) worldwide. The bacteria can be found in the back of the nose and throat of approximately 10-25% of the general population, particularly in children, teenagers, and young adults, without causing any symptoms or illness. However, when the bacterium invades the bloodstream and spreads to the brain or spinal cord, it can lead to life-threatening infections such as meningitis (inflammation of the membranes surrounding the brain and spinal cord) and septicemia (blood poisoning).

Neisseria meningitidis is classified into 12 serogroups based on the chemical structure of their capsular polysaccharides. The six major serogroups that cause most meningococcal disease worldwide are A, B, C, W, X, and Y. Vaccines are available to protect against some or all of these serogroups.

Meningococcal disease can progress rapidly, leading to severe symptoms such as high fever, headache, stiff neck, confusion, nausea, vomiting, and a rash consisting of purple or red spots. Immediate medical attention is required if someone experiences these symptoms, as meningococcal disease can cause permanent disabilities or death within hours if left untreated.

Immunoglobulin (Ig) Fab fragments are the antigen-binding portions of an antibody that result from the digestion of the whole antibody molecule by enzymes such as papain. An antibody, also known as an immunoglobulin, is a Y-shaped protein produced by the immune system to identify and neutralize foreign substances like bacteria, viruses, or toxins. The antibody has two identical antigen-binding sites, located at the tips of the two shorter arms, which can bind specifically to a target antigen.

Fab fragments are formed when an antibody is cleaved by papain, resulting in two Fab fragments and one Fc fragment. Each Fab fragment contains one antigen-binding site, composed of a variable region (Fv) and a constant region (C). The Fv region is responsible for the specificity and affinity of the antigen binding, while the C region contributes to the effector functions of the antibody.

Fab fragments are often used in various medical applications, such as immunodiagnostics and targeted therapies, due to their ability to bind specifically to target antigens without triggering an immune response or other effector functions associated with the Fc region.

Reperfusion injury is a complex pathophysiological process that occurs when blood flow is restored to previously ischemic tissues, leading to further tissue damage. This phenomenon can occur in various clinical settings such as myocardial infarction (heart attack), stroke, or peripheral artery disease after an intervention aimed at restoring perfusion.

The restoration of blood flow leads to the generation of reactive oxygen species (ROS) and inflammatory mediators, which can cause oxidative stress, cellular damage, and activation of the immune system. This results in a cascade of events that may lead to microvascular dysfunction, capillary leakage, and tissue edema, further exacerbating the injury.

Reperfusion injury is an important consideration in the management of ischemic events, as interventions aimed at restoring blood flow must be carefully balanced with potential harm from reperfusion injury. Strategies to mitigate reperfusion injury include ischemic preconditioning (exposing the tissue to short periods of ischemia before a prolonged ischemic event), ischemic postconditioning (applying brief periods of ischemia and reperfusion after restoring blood flow), remote ischemic preconditioning (ischemia applied to a distant organ or tissue to protect the target organ), and pharmacological interventions that scavenge ROS, reduce inflammation, or improve microvascular function.

In a medical context, "hot temperature" is not a standard medical term with a specific definition. However, it is often used in relation to fever, which is a common symptom of illness. A fever is typically defined as a body temperature that is higher than normal, usually above 38°C (100.4°F) for adults and above 37.5-38°C (99.5-101.3°F) for children, depending on the source.

Therefore, when a medical professional talks about "hot temperature," they may be referring to a body temperature that is higher than normal due to fever or other causes. It's important to note that a high environmental temperature can also contribute to an elevated body temperature, so it's essential to consider both the body temperature and the environmental temperature when assessing a patient's condition.

C-reactive protein (CRP) is a protein produced by the liver in response to inflammation or infection in the body. It is named after its ability to bind to the C-polysaccharide of pneumococcus, a type of bacteria. CRP levels can be measured with a simple blood test and are often used as a marker of inflammation or infection. Elevated CRP levels may indicate a variety of conditions, including infections, tissue damage, and chronic diseases such as rheumatoid arthritis and cancer. However, it is important to note that CRP is not specific to any particular condition, so additional tests are usually needed to make a definitive diagnosis.

Teichoic acids are complex polymers of glycerol or ribitol linked by phosphate groups, found in the cell wall of gram-positive bacteria. They play a crucial role in the bacterial cell's defense against hostile environments and can also contribute to virulence by helping the bacteria evade the host's immune system. Teichoic acids can be either linked to peptidoglycan (wall teichoic acids) or to membrane lipids (lipoteichoic acids). They can vary in structure and composition among different bacterial species, which can have implications for the design of antibiotics and other therapeutics.

Neuraminidase is an enzyme that occurs on the surface of influenza viruses. It plays a crucial role in the life cycle of the virus by helping it to infect host cells and to spread from cell to cell within the body. Neuraminidase works by cleaving sialic acid residues from glycoproteins, allowing the virus to detach from infected cells and to move through mucus and other bodily fluids. This enzyme is a major target of antiviral drugs used to treat influenza, such as oseltamivir (Tamiflu) and zanamivir (Relenza). Inhibiting the activity of neuraminidase can help to prevent the spread of the virus within the body and reduce the severity of symptoms.

Serine endopeptidases are a type of enzymes that cleave peptide bonds within proteins (endopeptidases) and utilize serine as the nucleophilic amino acid in their active site for catalysis. These enzymes play crucial roles in various biological processes, including digestion, blood coagulation, and programmed cell death (apoptosis). Examples of serine endopeptidases include trypsin, chymotrypsin, thrombin, and elastase.

Staphylococcus aureus is a type of gram-positive, round (coccal) bacterium that is commonly found on the skin and mucous membranes of warm-blooded animals and humans. It is a facultative anaerobe, which means it can grow in the presence or absence of oxygen.

Staphylococcus aureus is known to cause a wide range of infections, from mild skin infections such as pimples, impetigo, and furuncles (boils) to more severe and potentially life-threatening infections such as pneumonia, endocarditis, osteomyelitis, and sepsis. It can also cause food poisoning and toxic shock syndrome.

The bacterium is often resistant to multiple antibiotics, including methicillin, which has led to the emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains that are difficult to treat. Proper hand hygiene and infection control practices are critical in preventing the spread of Staphylococcus aureus and MRSA.

Endotoxins are toxic substances that are associated with the cell walls of certain types of bacteria. They are released when the bacterial cells die or divide, and can cause a variety of harmful effects in humans and animals. Endotoxins are made up of lipopolysaccharides (LPS), which are complex molecules consisting of a lipid and a polysaccharide component.

Endotoxins are particularly associated with gram-negative bacteria, which have a distinctive cell wall structure that includes an outer membrane containing LPS. These toxins can cause fever, inflammation, and other symptoms when they enter the bloodstream or other tissues of the body. They are also known to play a role in the development of sepsis, a potentially life-threatening condition characterized by a severe immune response to infection.

Endotoxins are resistant to heat, acid, and many disinfectants, making them difficult to eliminate from contaminated environments. They can also be found in a variety of settings, including hospitals, industrial facilities, and agricultural operations, where they can pose a risk to human health.

Complementary therapies refer to a group of diverse medical and health care systems, practices, and products that are not presently considered an integral part of conventional allopathic medicine. They are often used in conjunction with conventional treatments and are intended to facilitate the physical and emotional well-being of the patient. Complementary therapies can include a wide range of interventions such as acupuncture, chiropractic care, massage therapy, herbal medicine, yoga, meditation, guided imagery, hypnotherapy, and homeopathy, among others. It is important to note that while some complementary therapies have been shown to be effective for certain conditions, others lack scientific evidence of their safety and efficacy. Therefore, it is always recommended to consult with a healthcare provider before starting any new complementary therapy.

Polysaccharides are complex carbohydrates consisting of long chains of monosaccharide units (simple sugars) bonded together by glycosidic linkages. They can be classified based on the type of monosaccharides and the nature of the bonds that connect them.

Polysaccharides have various functions in living organisms. For example, starch and glycogen serve as energy storage molecules in plants and animals, respectively. Cellulose provides structural support in plants, while chitin is a key component of fungal cell walls and arthropod exoskeletons.

Some polysaccharides also have important roles in the human body, such as being part of the extracellular matrix (e.g., hyaluronic acid) or acting as blood group antigens (e.g., ABO blood group substances).

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Pneumococcal infections are illnesses caused by the bacterium Streptococcus pneumoniae, also known as pneumococcus. This bacterium can infect different parts of the body, including the lungs (pneumonia), blood (bacteremia or sepsis), and the covering of the brain and spinal cord (meningitis). Pneumococcal infections can also cause ear infections and sinus infections. The bacteria spread through close contact with an infected person, who may spread the bacteria by coughing or sneezing. People with weakened immune systems, children under 2 years of age, adults over 65, and those with certain medical conditions are at increased risk for developing pneumococcal infections.

Molecular weight, also known as molecular mass, is the mass of a molecule. It is expressed in units of atomic mass units (amu) or daltons (Da). Molecular weight is calculated by adding up the atomic weights of each atom in a molecule. It is a useful property in chemistry and biology, as it can be used to determine the concentration of a substance in a solution, or to calculate the amount of a substance that will react with another in a chemical reaction.

Flow cytometry is a medical and research technique used to measure physical and chemical characteristics of cells or particles, one cell at a time, as they flow in a fluid stream through a beam of light. The properties measured include:

* Cell size (light scatter)
* Cell internal complexity (granularity, also light scatter)
* Presence or absence of specific proteins or other molecules on the cell surface or inside the cell (using fluorescent antibodies or other fluorescent probes)

The technique is widely used in cell counting, cell sorting, protein engineering, biomarker discovery and monitoring disease progression, particularly in hematology, immunology, and cancer research.

Western blotting is a laboratory technique used in molecular biology to detect and quantify specific proteins in a mixture of many different proteins. This technique is commonly used to confirm the expression of a protein of interest, determine its size, and investigate its post-translational modifications. The name "Western" blotting distinguishes this technique from Southern blotting (for DNA) and Northern blotting (for RNA).

The Western blotting procedure involves several steps:

1. Protein extraction: The sample containing the proteins of interest is first extracted, often by breaking open cells or tissues and using a buffer to extract the proteins.
2. Separation of proteins by electrophoresis: The extracted proteins are then separated based on their size by loading them onto a polyacrylamide gel and running an electric current through the gel (a process called sodium dodecyl sulfate-polyacrylamide gel electrophoresis or SDS-PAGE). This separates the proteins according to their molecular weight, with smaller proteins migrating faster than larger ones.
3. Transfer of proteins to a membrane: After separation, the proteins are transferred from the gel onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric current in a process called blotting. This creates a replica of the protein pattern on the gel but now immobilized on the membrane for further analysis.
4. Blocking: The membrane is then blocked with a blocking agent, such as non-fat dry milk or bovine serum albumin (BSA), to prevent non-specific binding of antibodies in subsequent steps.
5. Primary antibody incubation: A primary antibody that specifically recognizes the protein of interest is added and allowed to bind to its target protein on the membrane. This step may be performed at room temperature or 4°C overnight, depending on the antibody's properties.
6. Washing: The membrane is washed with a buffer to remove unbound primary antibodies.
7. Secondary antibody incubation: A secondary antibody that recognizes the primary antibody (often coupled to an enzyme or fluorophore) is added and allowed to bind to the primary antibody. This step may involve using a horseradish peroxidase (HRP)-conjugated or alkaline phosphatase (AP)-conjugated secondary antibody, depending on the detection method used later.
8. Washing: The membrane is washed again to remove unbound secondary antibodies.
9. Detection: A detection reagent is added to visualize the protein of interest by detecting the signal generated from the enzyme-conjugated or fluorophore-conjugated secondary antibody. This can be done using chemiluminescent, colorimetric, or fluorescent methods.
10. Analysis: The resulting image is analyzed to determine the presence and quantity of the protein of interest in the sample.

Western blotting is a powerful technique for identifying and quantifying specific proteins within complex mixtures. It can be used to study protein expression, post-translational modifications, protein-protein interactions, and more. However, it requires careful optimization and validation to ensure accurate and reproducible results.

Membrane glycoproteins are proteins that contain oligosaccharide chains (glycans) covalently attached to their polypeptide backbone. They are integral components of biological membranes, spanning the lipid bilayer and playing crucial roles in various cellular processes.

The glycosylation of these proteins occurs in the endoplasmic reticulum (ER) and Golgi apparatus during protein folding and trafficking. The attached glycans can vary in structure, length, and composition, which contributes to the diversity of membrane glycoproteins.

Membrane glycoproteins can be classified into two main types based on their orientation within the lipid bilayer:

1. Type I (N-linked): These glycoproteins have a single transmembrane domain and an extracellular N-terminus, where the oligosaccharides are predominantly attached via asparagine residues (Asn-X-Ser/Thr sequon).
2. Type II (C-linked): These glycoproteins possess two transmembrane domains and an intracellular C-terminus, with the oligosaccharides linked to tryptophan residues via a mannose moiety.

Membrane glycoproteins are involved in various cellular functions, such as:

* Cell adhesion and recognition
* Receptor-mediated signal transduction
* Enzymatic catalysis
* Transport of molecules across membranes
* Cell-cell communication
* Immunological responses

Some examples of membrane glycoproteins include cell surface receptors (e.g., growth factor receptors, cytokine receptors), adhesion molecules (e.g., integrins, cadherins), and transporters (e.g., ion channels, ABC transporters).

Cricetinae is a subfamily of rodents that includes hamsters, gerbils, and relatives. These small mammals are characterized by having short limbs, compact bodies, and cheek pouches for storing food. They are native to various parts of the world, particularly in Europe, Asia, and Africa. Some species are popular pets due to their small size, easy care, and friendly nature. In a medical context, understanding the biology and behavior of Cricetinae species can be important for individuals who keep them as pets or for researchers studying their physiology.

Trypanosoma cruzi is a protozoan parasite that causes Chagas disease, also known as American trypanosomiasis. It's transmitted to humans and other mammals through the feces of triatomine bugs, often called "kissing bugs." The parasite can also be spread through contaminated food, drink, or from mother to baby during pregnancy or birth.

The life cycle of Trypanosoma cruzi involves two main forms: the infective metacyclic trypomastigote that is found in the bug's feces and the replicative intracellular amastigote that resides within host cells. The metacyclic trypomastigotes enter the host through mucous membranes or skin lesions, where they invade various types of cells and differentiate into amastigotes. These amastigotes multiply by binary fission and then differentiate back into trypomastigotes, which are released into the bloodstream when the host cell ruptures. The circulating trypomastigotes can then infect other cells or be taken up by another triatomine bug during a blood meal, continuing the life cycle.

Clinical manifestations of Chagas disease range from an acute phase with non-specific symptoms like fever, swelling, and fatigue to a chronic phase characterized by cardiac and gastrointestinal complications, which can develop decades after the initial infection. Early detection and treatment of Chagas disease are crucial for preventing long-term health consequences.

Immunologic cytotoxicity refers to the damage or destruction of cells that occurs as a result of an immune response. This process involves the activation of immune cells, such as cytotoxic T cells and natural killer (NK) cells, which release toxic substances, such as perforins and granzymes, that can kill target cells.

In addition, antibodies produced by B cells can also contribute to immunologic cytotoxicity by binding to antigens on the surface of target cells and triggering complement-mediated lysis or antibody-dependent cellular cytotoxicity (ADCC) by activating immune effector cells.

Immunologic cytotoxicity plays an important role in the body's defense against viral infections, cancer cells, and other foreign substances. However, it can also contribute to tissue damage and autoimmune diseases if the immune system mistakenly targets healthy cells or tissues.

A cell wall is a rigid layer found surrounding the plasma membrane of plant cells, fungi, and many types of bacteria. It provides structural support and protection to the cell, maintains cell shape, and acts as a barrier against external factors such as chemicals and mechanical stress. The composition of the cell wall varies among different species; for example, in plants, it is primarily made up of cellulose, hemicellulose, and pectin, while in bacteria, it is composed of peptidoglycan.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

Bacterial outer membrane proteins (OMPs) are a type of protein found in the outer membrane of gram-negative bacteria. The outer membrane is a unique characteristic of gram-negative bacteria, and it serves as a barrier that helps protect the bacterium from hostile environments. OMPs play a crucial role in maintaining the structural integrity and selective permeability of the outer membrane. They are involved in various functions such as nutrient uptake, transport, adhesion, and virulence factor secretion.

OMPs are typically composed of beta-barrel structures that span the bacterial outer membrane. These proteins can be classified into several groups based on their size, function, and structure. Some of the well-known OMP families include porins, autotransporters, and two-partner secretion systems.

Porins are the most abundant type of OMPs and form water-filled channels that allow the passive diffusion of small molecules, ions, and nutrients across the outer membrane. Autotransporters are a diverse group of OMPs that play a role in bacterial pathogenesis by secreting virulence factors or acting as adhesins. Two-partner secretion systems involve the cooperation between two proteins to transport effector molecules across the outer membrane.

Understanding the structure and function of bacterial OMPs is essential for developing new antibiotics and therapies that target gram-negative bacteria, which are often resistant to conventional treatments.

CHO cells, or Chinese Hamster Ovary cells, are a type of immortalized cell line that are commonly used in scientific research and biotechnology. They were originally derived from the ovaries of a female Chinese hamster (Cricetulus griseus) in the 1950s.

CHO cells have several characteristics that make them useful for laboratory experiments. They can grow and divide indefinitely under appropriate conditions, which allows researchers to culture large quantities of them for study. Additionally, CHO cells are capable of expressing high levels of recombinant proteins, making them a popular choice for the production of therapeutic drugs, vaccines, and other biologics.

In particular, CHO cells have become a workhorse in the field of biotherapeutics, with many approved monoclonal antibody-based therapies being produced using these cells. The ability to genetically modify CHO cells through various methods has further expanded their utility in research and industrial applications.

It is important to note that while CHO cells are widely used in scientific research, they may not always accurately represent human cell behavior or respond to drugs and other compounds in the same way as human cells do. Therefore, results obtained using CHO cells should be validated in more relevant systems when possible.

Immunoglobulin A (IgA) is a type of antibody that plays a crucial role in the immune function of the human body. It is primarily found in external secretions, such as saliva, tears, breast milk, and sweat, as well as in mucous membranes lining the respiratory and gastrointestinal tracts. IgA exists in two forms: a monomeric form found in serum and a polymeric form found in secretions.

The primary function of IgA is to provide immune protection at mucosal surfaces, which are exposed to various environmental antigens, such as bacteria, viruses, parasites, and allergens. By doing so, it helps prevent the entry and colonization of pathogens into the body, reducing the risk of infections and inflammation.

IgA functions by binding to antigens present on the surface of pathogens or allergens, forming immune complexes that can neutralize their activity. These complexes are then transported across the epithelial cells lining mucosal surfaces and released into the lumen, where they prevent the adherence and invasion of pathogens.

In summary, Immunoglobulin A (IgA) is a vital antibody that provides immune defense at mucosal surfaces by neutralizing and preventing the entry of harmful antigens into the body.

Neutralization tests are a type of laboratory assay used in microbiology and immunology to measure the ability of a substance, such as an antibody or antitoxin, to neutralize the activity of a toxin or infectious agent. In these tests, the substance to be tested is mixed with a known quantity of the toxin or infectious agent, and the mixture is then incubated under controlled conditions. After incubation, the mixture is tested for residual toxicity or infectivity using a variety of methods, such as cell culture assays, animal models, or biochemical assays.

The neutralization titer is then calculated based on the highest dilution of the test substance that completely neutralizes the toxin or infectious agent. Neutralization tests are commonly used in the diagnosis and evaluation of immune responses to vaccines, as well as in the detection and quantification of toxins and other harmful substances.

Examples of neutralization tests include the serum neutralization test for measles antibodies, the plaque reduction neutralization test (PRNT) for dengue virus antibodies, and the cytotoxicity neutralization assay for botulinum neurotoxins.

Inflammation is a complex biological response of tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. It is characterized by the following signs: rubor (redness), tumor (swelling), calor (heat), dolor (pain), and functio laesa (loss of function). The process involves the activation of the immune system, recruitment of white blood cells, and release of inflammatory mediators, which contribute to the elimination of the injurious stimuli and initiation of the healing process. However, uncontrolled or chronic inflammation can also lead to tissue damage and diseases.

Protein isoforms are different forms or variants of a protein that are produced from a single gene through the process of alternative splicing, where different exons (or parts of exons) are included in the mature mRNA molecule. This results in the production of multiple, slightly different proteins that share a common core structure but have distinct sequences and functions. Protein isoforms can also arise from genetic variations such as single nucleotide polymorphisms or mutations that alter the protein-coding sequence of a gene. These differences in protein sequence can affect the stability, localization, activity, or interaction partners of the protein isoform, leading to functional diversity and specialization within cells and organisms.

Genotype, in genetics, refers to the complete heritable genetic makeup of an individual organism, including all of its genes. It is the set of instructions contained in an organism's DNA for the development and function of that organism. The genotype is the basis for an individual's inherited traits, and it can be contrasted with an individual's phenotype, which refers to the observable physical or biochemical characteristics of an organism that result from the expression of its genes in combination with environmental influences.

It is important to note that an individual's genotype is not necessarily identical to their genetic sequence. Some genes have multiple forms called alleles, and an individual may inherit different alleles for a given gene from each parent. The combination of alleles that an individual inherits for a particular gene is known as their genotype for that gene.

Understanding an individual's genotype can provide important information about their susceptibility to certain diseases, their response to drugs and other treatments, and their risk of passing on inherited genetic disorders to their offspring.

A kidney, in medical terms, is one of two bean-shaped organs located in the lower back region of the body. They are essential for maintaining homeostasis within the body by performing several crucial functions such as:

1. Regulation of water and electrolyte balance: Kidneys help regulate the amount of water and various electrolytes like sodium, potassium, and calcium in the bloodstream to maintain a stable internal environment.

2. Excretion of waste products: They filter waste products from the blood, including urea (a byproduct of protein metabolism), creatinine (a breakdown product of muscle tissue), and other harmful substances that result from normal cellular functions or external sources like medications and toxins.

3. Endocrine function: Kidneys produce several hormones with important roles in the body, such as erythropoietin (stimulates red blood cell production), renin (regulates blood pressure), and calcitriol (activated form of vitamin D that helps regulate calcium homeostasis).

4. pH balance regulation: Kidneys maintain the proper acid-base balance in the body by excreting either hydrogen ions or bicarbonate ions, depending on whether the blood is too acidic or too alkaline.

5. Blood pressure control: The kidneys play a significant role in regulating blood pressure through the renin-angiotensin-aldosterone system (RAAS), which constricts blood vessels and promotes sodium and water retention to increase blood volume and, consequently, blood pressure.

Anatomically, each kidney is approximately 10-12 cm long, 5-7 cm wide, and 3 cm thick, with a weight of about 120-170 grams. They are surrounded by a protective layer of fat and connected to the urinary system through the renal pelvis, ureters, bladder, and urethra.

Immunohistochemistry (IHC) is a technique used in pathology and laboratory medicine to identify specific proteins or antigens in tissue sections. It combines the principles of immunology and histology to detect the presence and location of these target molecules within cells and tissues. This technique utilizes antibodies that are specific to the protein or antigen of interest, which are then tagged with a detection system such as a chromogen or fluorophore. The stained tissue sections can be examined under a microscope, allowing for the visualization and analysis of the distribution and expression patterns of the target molecule in the context of the tissue architecture. Immunohistochemistry is widely used in diagnostic pathology to help identify various diseases, including cancer, infectious diseases, and immune-mediated disorders.

Graft rejection is an immune response that occurs when transplanted tissue or organ (the graft) is recognized as foreign by the recipient's immune system, leading to the activation of immune cells to attack and destroy the graft. This results in the failure of the transplant and the need for additional medical intervention or another transplant. There are three types of graft rejection: hyperacute, acute, and chronic. Hyperacute rejection occurs immediately or soon after transplantation due to pre-existing antibodies against the graft. Acute rejection typically occurs within weeks to months post-transplant and is characterized by the infiltration of T-cells into the graft. Chronic rejection, which can occur months to years after transplantation, is a slow and progressive process characterized by fibrosis and tissue damage due to ongoing immune responses against the graft.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Complement C5a, des-Arginine is a derivative of the complement component C5a. The complement system is a group of proteins that are part of the body's immune defense against foreign invaders such as bacteria and viruses. When activated, the complement system can help to eliminate pathogens by attracting immune cells to the site of infection, promoting inflammation, and directly killing the pathogen.

C5a is a small protein that is generated when the complement component C5 is cleaved during the activation of the complement system. C5a is a potent anaphylatoxin, which means it can cause the release of histamine from mast cells and basophils, leading to increased vascular permeability, smooth muscle contraction, and recruitment of immune cells to the site of infection.

Des-Arginine refers to the removal of an arginine residue from the C-terminus of C5a. This modified form of C5a is known as C5a-desArg and has reduced pro-inflammatory activity compared to intact C5a. However, it can still contribute to the regulation of the immune response by interacting with specific receptors on immune cells.

In summary, Complement C5a, des-Arginine is a derivative of the complement component C5a that has reduced pro-inflammatory activity due to the removal of an arginine residue from its C-terminus.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

The alternative pathway is one of three complement pathways that opsonize and kill pathogens. The pathway is triggered when the ... The alternative pathway is a type of cascade reaction of the complement system and is a component of the innate immune system, ... Alternative pathway activation also plays a significant role in complement-mediated renal disorders such as atypical hemolytic ... Classical complement pathway Lectin pathway Conrad DH, Carlo JR, Ruddy S (June 1978). "Interaction of beta1H globulin with cell ...
Alternative complement pathway - another complement system pathway Lectin pathway - another complement system pathway Noris, ... Activation of the complement pathway through the classical, lectin or alternative complement pathway is followed by a cascade ... The classical complement pathway is one of three pathways which activate the complement system, which is part of the immune ... The classical pathway is distinct from the other complement pathways in its unique activation triggers and cascade sequence. ...
... the classical complement pathway, the alternative complement pathway, and the lectin pathway. The alternative pathway accounts ... Accordingly, the alternative complement pathway is one element of innate immunity.[citation needed] Once the alternative C3 ... Alternative Complement Pathway) Inflammation - by attracting macrophages and neutrophils. (Lectin pathway) Most of the proteins ... Polymorphisms of complement component 3, complement factor B, and complement factor I, as well as deletion of complement factor ...
In the alternative complement pathway, C3 is cleaved by C3bBb, another form of C3-convertase composed of activated forms of C3 ... Its activation is required for both classical and alternative complement activation pathways. People with C3 deficiency are ... The resultant complex, C3bBb, is called the alternative pathway (AP) C3 convertase. C3bBb is deactivated in steps. First, the ... "Entrez Gene: C3 complement component 3". Sahu A, Lambris JD (Apr 2001). "Structure and biology of complement protein C3, a ...
"Biosynthesis of the complement components and the regulatory proteins of the alternative complement pathway by human peripheral ... Maga TK, Nishimura CJ, Weaver AE, Frees KL, Smith RJ (June 2010). "Mutations in alternative pathway complement proteins in ... This contribution is thought to be due to the dysregulation of the alternative pathway, leading to increased inflammation in ... Complement factor I, also known as C3b/C4b inactivator, is a protein that in humans is encoded by the CFI gene. Complement ...
Most cases are associated with the dysregulation of the alternative complement pathway. DDD is associated with deposition of ... immunoglobulin suggested to early investigators that DDD was due to abnormal activation of the complement alternative pathway ( ... It is believed to be associated with the classical complement pathway. Also called recently as 'C3 nephropathy' The preferred ... Type III is very rare, it is characterized by a mixture of subepithelial and subendothelial immune and/or complement deposits. ...
Hourcade D (2006). "The Role of Properdin in the Assembly of the Alternative Pathway C3 Convertases of Complement". J Biol Chem ... The alternative pathway is not dependent on antibodies. This branch of the complement system is activated by IgA immune ... a Positive Regulator of the Alternative Pathway of Complement". J Biol Chem. 259 (7): R4582-4588. doi:10.1016/S0021-9258(17) ... It binds to preformed alternative pathway C3-convertases. Properdin also inhibits the Factor H - mediated cleavage of C3b by ...
This gene encodes complement factor B, a component of the alternative pathway of complement activation. Factor B circulates in ... Upon activation of the alternative pathway, it is cleaved by complement factor D yielding the noncatalytic chain Ba and the ... components of the alternative-pathway C3 convertase of complement". The Biochemical Journal. 253 (3): 667-75. doi:10.1042/ ... the major zymogen protease of the alternative complement pathway". The Journal of Investigative Dermatology. 98 (3): 379-83. ...
"Activation of the alternative pathway of complement by a phosphorothioate oligonucleotide: potential mechanism of action". The ... Cytosolic nucleic acid-sensing pathways can enhance immune response to cancer. RIG-I agonist, stem loop RNA (SLR) 14. Tumor ... As a therapeutic, miRNA has the potential to affect biochemical pathways throughout the organism. With more than 400 miRNA ... Houseley J, Tollervey D (February 2009). "The many pathways of RNA degradation". Cell. 136 (4): 763-76. doi:10.1016/j.cell. ...
A Type III Complement Factor D Deficiency: Structural insights for inhibition of the alternative pathway. J. Allergy Clin. ...
Alternative pathway hemolytic assay ("AH50") can be used in conjunction to indicate if there is a terminal pathway deficiency ( ... "Simplified assays of hemolytic activity of the classical and alternative complement pathways". Journal of Immunological Methods ... CH50 and AH50 both are low), classical pathway deficiency (CH50 low, AH50 normal) or alternative pathway deficiency (AH50 low, ... For example, if and individual has normal C3/C4 values but a decreased CH50, that can indicate a terminal complement pathway ...
The alternative pathway of complement activation is typically always active at low levels in blood plasma through a process ... The classical pathway of complement activation is initiated when the C1 complex, made up of C1r and C1s serine proteases, ... Other than the alternative pathway, which is constantly active, C3a formation is triggered by pathogenic infection. ... 12th European Meeting on Complement in Human Disease12th European Meeting on CHD12th European Meeting on Complement in Human ...
M protein also inhibits opsonization by the alternative complement pathway by binding to host complement regulators. The M ... Whilst Rgg2/3 pathway increases biofilm, the RopB pathway disrupts it. RopB is another Rgg-like protein (Rgg1) that directly ... One of the biofilm forming pathways in GAS is the Rgg2/3 pathway. It regulates SHP's (short hydrophobic peptides) that are ... In the cytosol the pheromones have two functions in the Rgg2/3 pathway. Firstly, they inhibit the activity of Rgg3 which is a ...
Hourcade D (2006). "The Role of Properdin in the Assembly of the Alternative Pathway C3 Convertases of Complement". J Biol Chem ... C3 convertase can be used to refer to the form produced in the alternative pathway (C3bBb) or the classical and lectin pathways ... C3 convertase formation can occur in three different pathways: the classical, lectin, and alternative pathways. Cleavage of ... "C3b deposition during activation of the alternative complement pathway and the effect of deposition on the activating surface ...
A NOVEL ORAL COMPLEMENT ALTERNATIVE PATHWAY FACTOR B INHIBITOR FOR THE TREATMENT OF GLOMERULAR DISEASE. Nephrology Dialysis ...
Different complement receptors can participate in either the classical complement pathway, the alternative complement pathway, ... All four complement receptors can bind to fragments of complement component 3 or complement component 4 coated on pathogen ... A complement receptor is a membrane-bound receptor belonging to the complement system, which is part of the innate immune ... Mutations in complement receptors which alter receptor function can also increase risk of certain diseases. Complement system ...
The complement system can be activated through three pathways: the classical pathway, the alternative pathway, and the lectin ... Binding of MBL to a micro-organism results in activation of the lectin pathway of the complement system. Another important ... The subsequent complement cascade catalyzed by C3-convertase results in creating a membrane attack complex, which causes lysis ... In order to activate the complement system when MBL binds to its target (for example, mannose on the surface of a bacterium), ...
... is involved in the alternative complement pathway of the complement system where it cleaves factor B. The protein ... The encoded protein is a component of the alternative complement pathway best known for its role in humoral suppression of ... Lesavre, PH; Müller-Eberhard, HJ (1 December 1978). "Mechanism of action of factor D of the alternative complement pathway". ... Role of MASP-3 in the Physiological Activation of Factor D of the Alternative Complement Pathway". Journal of Immunology. 203 ( ...
C3 nephritic factor is a serum immunoglobulin G that interacts with the C3bBb alternative pathway convertase to activate C3. C3 ... Complement dysfunction may predispose some patients to bacterial infections. The diagnosis of the disease is mainly clinical ( ... Around 83% of APL patients had low complement 3 (C3) levels and the presence of polyclonal immunoglobulin C3 nephritic factor. ... Lipodystrophy is often associated with glomerulonephritis, low C3 serum complement levels, and the presence of a C3 nephritic ...
The complement pathway is composed of several subset pathways: the lectin/mannose pathway, alternative pathway and the ... classical complement pathway). In brief, the crucial role of C1q in the pathway is its importance as the first protein to start ... in the complement pathway) named C1-inhibitor. The inhibition of C1-inhibitor leads to over-activation of the complement ... which instigates activation of the entire complement pathway. Consequently, levels of all complement proteins become low. ...
The formation of the MAC occurs through three distinct pathways: the classical, alternative, and lectin pathways. Pore ... Complement component 9 (C9) is a MACPF protein involved in the complement system, which is part of the innate immune system. ... C9 is one member of the complement membrane attack complex (MAC), which also includes complement components C5b, C6, C7 and C8 ... Complement+9 at the U.S. National Library of Medicine Medical Subject Headings (MeSH) PDBe-KB provides an overview of all the ...
... thus preventing amplification of the complement cascade through the alternative pathway. Complement factor I can further cleave ... iC3b is produced when complement factor I cleaves C3b. Complement receptors on white blood cells are able to bind iC3b, so iC3b ... iC3b is a protein fragment that is part of the complement system, a component of the vertebrate immune system. ... v t e (Complement system, All stub articles, Biochemistry stubs). ...
All three pathways of the complement system (classical, lectin and alternative pathways) initiate the formation of MAC. Another ... Terminal complement pathway deficiency Paroxysmal nocturnal haemoglobinuria Perforin Pore-forming toxin Xie CB, Jane-Wit D, ... ISBN 978-0-323-54943-1. Media related to Complement membrane attack complex at Wikimedia Commons Complement+Membrane+Attack+ ... two regulators of complement. The membrane attack complex is initiated when the complement protein C5 convertase cleaves C5 ...
The classical pathway, lectin pathway, and alternative pathway of complement are all involved in glomerulonephritis, depending ... There are no current clinical trials for DPGN happening.[citation needed] Activating complement pathways plays a large role in ... There are currently drugs available that will target the complement pathway. It has been proposed that if fluorescently tagged ... then identification of specific pathways involved and the accumulated complement proteins in the glomeruli should be achievable ...
To support this thesis, he has 1) determined how the alternative complement pathway of innate immunity attaches C3 to microbial ...
... alternative pathway). Interaction of DAF with cell-associated C4b of the classical and lectin pathways interferes with the ... Complement decay-accelerating factor, also known as CD55 or DAF, is a protein that, in humans, is encoded by the CD55 gene. DAF ... and interaction of DAF with C3b of the alternative pathway interferes with the conversion of factor B to Bb by factor D, ... thereby preventing formation of the C3bBb C3 convertase of the alternative pathway. Thus, by limiting the amplification ...
Complement Factor D is a member of the trypsin family of peptidases and is a component of the alternative complement pathway. ... The product candidate is also referred to as "FCFD4514S" or "RG7417". The drug is designed to inhibit complement activation and ... Other than the therapeutic antibodies, which target the IgE allergic pathway, immune factors, and CD4, Tanox also possessed ... an Fab fragment of a humanized antibody against Factor D of the human immune complement system to be tested for treating ...
Binding to the complement factor H allows for meningococcus to grow in human blood while blocking alternative pathways. This ... Reverse vaccinology also led to the discovery of factor G binding protein in meningococcus, which binds to complement factor H ... The Pathway from Genomes and Epitope Predictions to Tailored Recombinant Vaccines", Vaccine Design: Methods and Protocols: ... model does not fit many animal species, which do not have the same complement factor H as humans, indicating differentiation of ...
... directly activates the alternative complement pathway and also interferes with complement regulation by binding to complement ... 2009). "Alternative pathway of complement in children with diarrhea-associated hemolytic uremic syndrome". Clin J Am Soc ... Later, mutations in complement factor H, complement factor I, membrane cofactor protein, factor B, C3, and thrombomodulin have ... 2009). "Complement inhibitor eculizumab in atypical hemolytic uremic syndrome". Clin J Am Soc Nephrol. 4 (8): 1312-1316. doi: ...
Croize J, Arvieux J, Berche P, Colomb MG (December 1993). "Activation of the human complement alternative pathway by Listeria ... The three different complement systems are classical, alternative and lectin. Classical: starts when antibody binds to bacteria ... The complement system is a biochemical cascade of the immune system that helps, or "complements", the ability of antibodies to ... Alternative: starts "spontaneously" Lectin: starts when lectins bind to mannose on bacteria Elements of the complement cascade ...
The alternative pathway is one of three complement pathways that opsonize and kill pathogens. The pathway is triggered when the ... The alternative pathway is a type of cascade reaction of the complement system and is a component of the innate immune system, ... Alternative pathway activation also plays a significant role in complement-mediated renal disorders such as atypical hemolytic ... Classical complement pathway Lectin pathway Conrad DH, Carlo JR, Ruddy S (June 1978). "Interaction of beta1H globulin with cell ...
Santiago Rodríguez de Córdoba on Physiopathological implications of genetic variability in the complement alternative pathway, ... The evolution of complement and the alternative pathway The evolution of complement and the alternative pathway ... Physiopathological implications of genetic variability in the complement alternative pathway. *Prof. Santiago Rodríguez de ... Physiopathological Implication of Genetic Variability in the Complement Alternative Pathway. My name is Santiago Rodriguez de ...
Evasion of the alternative complement pathway by Photorhabdus spp. / Beeton, Michael L; Vlisidou, Isabella; Spiller, O et al. ... Evasion of the alternative complement pathway by Photorhabdus spp. In: Molecular Immunology. 2011 ; Vol. 48, No. 14. pp. 1703- ... Evasion of the alternative complement pathway by Photorhabdus spp. Michael L Beeton, Isabella Vlisidou, O Spiller, R Waterfield ... Beeton ML, Vlisidou I, Spiller O, Waterfield R. Evasion of the alternative complement pathway by Photorhabdus spp. Molecular ...
... and inhibits complement activation via classical (IC50 = 110.8 nM) and alternative (IC50 = 291.3 nM) pathways in Wieslab assays ... Nanofitins® efficiently inhibit complement pathway by targeting C3/C3b. Affilogic discovery process was engaged to identify ... The proof of concept of inhibition of different complement pathways has been demonstrated in rodents and non-human-primate (NHP ... Garlich et al., Discovery of APL-1030, a Novel, High-Affinity Nanofitin Inhibitor of C3-Mediated Complement Activation, ...
Complement Pathway ELISA is a qualitative/semiquantitative test that detects activation of the complement system alternative ... Mouse Alternative Complement Pathway ELISA Assay Kit. $1,190.00. The Mouse Alternative Complement Pathway ELISA Assay Kit is a ... Mouse Alternative Complement Pathway ELISA Assay Kit. The Mouse Alternative Complement Pathway ELISA Assay Kit is For Research ... Rat Alternative Complement Pathway ELISA Assay Kit. Pig Alternative Complement Pathway ELISA Assay Kit. Mouse Classical ...
... complement: …occurs by three pathways: the classical pathway, the lectin pathway, and the alternative pathway (or properdin ... The classical pathway is triggered by groups of antibodies bound to the surfaces of a microorganism, while the lectin pathway ... system). A different type of signal activates each pathway. ... In complement. …occurs by three pathways: the classical pathway ... the lectin pathway, and the alternative pathway (or properdin system). A different type of signal activates each pathway. The ...
Properdin, a positive regulator of the complement system, has recently been reported to bind to certain pathogenic ... thus providing a platform for de novo convertase assembly and complement activation. These studies, with some contradictory ... which is in agreement with the reported role for properdin as a complement initiator. ... first time that the physiological forms of human properdin can selectively recognize surfaces and enhance or promote complement ...
The top scored pathway was "complement activation, alternative pathway", and several proteins involved in this pathway were ... Gingival Exudatome Dynamics Implicate Inhibition of the Alternative Complement Pathway in the Protective Action of the C3 ... exudate of cynomolgus monkey periodontitis in response to C3 inhibition and identified the alternative pathway of complement ... Although complement inhibition has been successfully used to treat periodontitis in animal models, studies globally analyzing ...
Kinetic analysis of the interaction between the complement regulators CD46 and CD55 and components of the alternative pathway ... Kinetic analysis of the interaction between the complement regulators CD46 and CD55 and components of the alternative pathway ...
Inefficient binding of alternative pathway complement components to serotypes B and C may contribute to the relative difficulty ... Inefficient binding of alternative pathway complement components to serotypes B and C may contribute to the relative difficulty ... Inefficient binding of alternative pathway complement components to serotypes B and C may contribute to the relative difficulty ... Inefficient binding of alternative pathway complement components to serotypes B and C may contribute to the relative difficulty ...
... of the alternative complement pathway and that a novel complement activation site targeted inhibitor of the alternative pathway ... Subretinal Rather Than Intravitreal Adeno-Associated Virus-Mediated Delivery of a Complement Alternative Pathway Inhibitor Is ... Subretinal Rather Than Intravitreal Adeno-Associated Virus-Mediated Delivery of a Complement Alternative Pathway Inhibitor Is ... Results: RPE- but not RGC-mediated secretion of CR2-fH was found to reduce SIOP and complement activation in RPE/choroid. ...
Learn about the three pathways lead to complement activation and some of their key inhibitors. ... The alternative pathway. The alternative pathway of complement activation is in a constant state of low-level activation (known ... Note, C3b generated in the classical pathway feeds into the alternative pathway to amplify the activation of complement. ... The alternative pathway is regulated by Factor H, CD55 and CD35, which inhibit the C3 convertase of the alternative pathway. ...
Predicted to be involved in complement activation; proteolysis; and regulation of complement activation, alternative pathway. ... complement factor H-related 4. MGI:3646434 Go Annotations as Summary Text (Tabular View) (GO Graph). Automated description from ... Orthologous to human CFH (complement factor H).. Go Annotations in Tabular Form (Text View) (GO Graph) Filter annotations by: ... Enables complement component C3b binding activity and heparin binding activity. ...
... which can be split into terminal and proximal complement inhibitors. Many novel terminal complement inhibitors are now in ... which can be split into terminal and proximal complement inhibitors. Many novel terminal complement inhibitors are now in ... At the moment there are three strategies of proximal complement inhibition: anti-C3 agents, anti-factor D agents and anti- ... Indeed, we envision a new scenario of therapeutic complement inhibition, where proximal inhibitors (either anti-C3, anti-FD or ...
Another big bucket is complement inhibitors. As best we can tell, the alternative and lectin pathway are both involved in IgA ... The classical pathway is not. People are testing different drugs that inhibit either the alternative pathway alone, like a ... factor B inhibitor, for example, the lectin pathway alone, or the terminal complement cascade. We should keep an eye on those ...
Furthermore, the alternative pathway of complement is absent in the CSF. By contrast, CSF is a good growth medium for the ... Itraconazole 200 mg/day can be an alternative to fluconazole, but it is less effective. There is limited data for use of the ... Amphotericin B (1 mg/kg/wk) is less effective than fluconazole, but it is an alternative for patients who experience relapse on ... oral therapy is an important alternative. Results of a randomized trial suggest that a 2-week course of high-dose fluconazole ( ...
The normal complement system consists of the classic and alternative pathways. The classic pathway is activated by the ... The alternative pathway utilizes C3 and factors B and D to form the alternative pathway convertase C3b,Bb. ... indicating activation of the alternative complement pathway. Signs of activation of the classic pathway are minimal, and ... NFa stabilizes the alternative pathway convertase and results in complement activation and chronic C3 consumption. Deficiency ...
The Alternative Complement Pathway Deficiency Amerliorates Chronic Smoked-Induced Functional And Morphological Ocular Injury. ... The Alternative Complement Pathway Mediates Functional And Morphological Deficits In A Smoke Model Of Age-Related Macular ...
... the classical pathway, the alternative pathway and the mannose-binding lectin (MBL) pathway (Figure 1). All three pathways ... Figure 1 Complement activation pathways. Complement activation is triggered via activation of either the alternative, classical ... The third complement activation pathway, the lectin-binding pathway, is homologous to the classical pathway except that it is ... In vitro alternative pathway activation of complement by the brush border of proximal tubules of normal rat kidney. J Immunol. ...
... alternative pathway; CFHR: complement factor H-related; CP: classical pathway; CR1: complement receptor 1; FB: factor B; FD: ... NETosing neutrophils activate complement both on their own NETs and bacteria via alternative and non-alternative pathways. ... Complement alternative pathway acts as a positive feedback amplification of neutrophil activation. Blood 2011;117:1340-9. ... Activation of the complement system occurs through the classical (CP), lectin (LP), or alternative (AP) pathways. The CP is ...
We investigated ADAMTS13 and complement alternative pathway (CAP) activity as previously described (16). ... Frémeaux-Bacchi V, Sellier-Leclerc A-L, Vieira-Martins P, Limou S, Kwon T, Lahoche A, et al. Complement gene variants and Shiga ... Screening for variants in complement genes is not usually conducted among children with STEC-associated HUS. Similarly, it ... However, a decrease in the concentration of complement factors, the interpretation of which remains equivocal, might be ...
Inefficiency in the neonates alternative complement pathway compromises their defense against encapsulated bacteria [3] ...
... and fibroblasts to promote wound healing and can initiate the alternative complement pathway to inhibit sepsis caused by Gram- ... Minami, S., Suzuki, H., Okamoto, Y., Fujinaga, T. & Shigemasa, Y. Chitin and chitosan activate complement via the alternative ... TLR2, TLR4 and the MYD88 Signaling Pathway Are Crucial for Neutrophil Migration in Acute Kidney Injury Induced by Sepsis. PloS ... Chitohexaose activates macrophages by alternate pathway through TLR4 and blocks endotoxemia. PLoS pathogens 8, e1002717, https ...
Complement is a blood test that measures the activity of certain proteins in the liquid portion of your blood. ... Complement is a blood test that measures the activity of certain proteins in the liquid portion of your blood. ... with some bacterial blood infections and shock often have very low C3 and components of whats known as the alternative pathway ... The "complement cascade" is a series of reactions that take place in the blood. The cascade activates the complement proteins. ...
Complement System and Immunology; Allergic Disorders - Learn about from the MSD Manuals - Medical Professional Version. ... Complement activation pathways. The classical, lectin, and alternative pathways converge into a final common pathway when C3 ... There are 3 pathways of complement activation (see figure Complement activation pathways Complement activation pathways ): ... see figure Complement activation pathways Complement activation pathways ). C3 cleavage may result in formation of the membrane ...
Devine, D.V.; Falk, R.J.; Balber, A.E. Restriction of the alternative pathway of human complement by intact Trypanosoma brucei ... Rurangirwa, F.R.; Tabel, H.; Losos, G.; Tizard, I.R. Hemolytic complement and serum C3 levels in Zebu cattle infected with ... This not only allows the removal of VSG-bound antibodies, but also reduces the efficacy of complement-mediated killing after ... This pathology involves the disruption of regular B cell affinity maturation pathways, as well as the induction of low-affinity ...
aHUS is a condition associated with alternative pathway complement dysregulation. It is characterized by thrombotic ... Complement C3. Complement C4. ADAMTS 13 Activity. Initial results. 1.7mg/dl. 45mg/dl. 9.4g/dl. 37000/ul. 1+. 341U/L. 27.4SGU. > ...
Teoh CW, Riedl M, Licht C. The alternative pathway of complement and the thrombotic microangiopathies. The Journal of ... Guidelines, pathways and other documents to guide health care professionals in the management of specific health conditions. ... complement-mediated injury in transplantation and improving long-term outcomes in paediatric transplantation. ... University of Toronto studying the role of complement in calcineurin inhibitor-induced endothelial cell toxicity. ...
A complement atlas identifies interleukin-6-dependent alternative pathway dysregulation as a key druggable feature of COVID-19 ... A Complement Atlas identifies interleukin 6 dependent alternative pathway dysregulation as a key druggable feature of COVID-19 ...
A Complement Atlas identifies interleukin 6 dependent alternative pathway dysregulation as a key druggable feature of COVID-19 ... Efficacy and safety of the investigational complement C5 inhibitor zilucoplan in patients hospitalized with COVID-19 : an open- ...
  • This convertase, the alternative pathway C3-convertase, although only produced in small amounts, can cleave multiple C3 proteins into C3a and C3b. (wikipedia.org)
  • The addition of properdin forms the complex C3bBbP, a stable compound which can bind an additional C3b to form alternative pathway C5-convertase. (wikipedia.org)
  • The C5-convertase of the alternative pathway consists of (C3b)2BbP (sometimes referred to as C3b2Bb). (wikipedia.org)
  • After the creation of C5 convertase (either as (C3b)2BbP or C4b2b3b from the classical pathway), the complement system follows the same path regardless of the means of activation (alternative, classical, or lectin). (wikipedia.org)
  • Properdin, a positive regulator of the complement system, has recently been reported to bind to certain pathogenic microorganisms, to early or late apoptotic and necrotic cells, and to particular live human cell lines, thus providing a platform for de novo convertase assembly and complement activation. (utoledo.edu)
  • We conclude that the relatively high degree of side chain substitution of capsular polysaccharide from C. neoformans variety gattii contributes to inefficient surface assembly of the alternative pathway C3 convertase. (johnshopkins.edu)
  • C2a remains associated with C4b to form the classical pathway C3 convertase (C4b2a). (abcam.com)
  • The latter binds to the C3 convertase complex to form C4b2a3b, the classical pathway C5 convertase. (abcam.com)
  • This interaction results in the formation of C4b2a, which is the classic pathway C3b convertase. (medscape.com)
  • The alternative pathway utilizes C3 and factors B and D to form the alternative pathway convertase C3b,Bb. (medscape.com)
  • Small amounts of C3b are constantly being formed in the circulation, which are inactivated by factors H and I. The binding of C3b to a foreign antigen decreases its affinity for factor H and allows for the formation of increasing amounts of the alternate pathway convertase. (medscape.com)
  • C3b is an opsonin itself, and C3 convertase facilitates the activation of the terminal pathway and the formation of the membrane attack complex C5b-9. (medscape.com)
  • The classical, lectin, and alternative pathways converge into a final common pathway when C3 convertase (C3 con) cleaves C3 into C3a and C3b. (msdmanuals.com)
  • Properdin (FP) is a positive regulator of the immune system stimulating the activity of the proteolytically active C3 convertase C3bBb in the alternative pathway of the complement system. (rcsb.org)
  • Its processing by C3 convertase is the central reaction in both classical and alternative complement pathways. (abcam.com)
  • C3 nephritic factor is a serum immunoglobulin G that interacts with the C3bBb alternative pathway convertase to activate C3. (medscape.com)
  • Adipocytes synthesize C3, factor B, and factor D (adipsin), which allows C3bBb to be formed locally, but which usually does not result in the activation of the terminal lytic part of the complement pathway (C5-9).The IgG antibody, C3Nef, prevents the alternative complement C3-convertase C3Bb from dissociative inactivation, resulting in adipocyte lysis. (medscape.com)
  • The proof of concept of inhibition of different complement pathways has been demonstrated in rodents and non-human-primate (NHP) models. (affilogic.com)
  • Gingival Exudatome Dynamics Implicate Inhibition of the Alternative Complement Pathway in the Protective Action of the C3 Inhibitor Cp40 in Nonhuman Primate Periodontitis. (bvsalud.org)
  • Although complement inhibition has been successfully used to treat periodontitis in animal models , studies globally analyzing inflamed tissue proteins to glean insight into possible mechanisms of action are missing. (bvsalud.org)
  • We mapped the proteomic fingerprint changes in local tissue exudate of cynomolgus monkey periodontitis in response to C3 inhibition and identified the alternative pathway of complement activation and leukocyte degranulation as main targets, which are thus likely to play significant roles in periodontal disease pathogenesis . (bvsalud.org)
  • Conclusions: Our results suggest that complement inhibition for AMD-like pathology is required basal to the RPE and argues in favor of AAV vector delivery to the RPE or outside the blood-retina barrier. (marclab.org)
  • Anti-complement Treatment for Paroxysmal Nocturnal Hemoglobinuria: Time for Proximal Complement Inhibition? (frontiersin.org)
  • At the moment there are three strategies of proximal complement inhibition: anti-C3 agents, anti-factor D agents and anti-factor B agents. (frontiersin.org)
  • Preliminary data clearly demonstrate that proximal complement inhibition is pharmacologically feasible and apparently safe, and may drastically improve the hematological response to complement inhibition in PNH. (frontiersin.org)
  • Indeed, we envision a new scenario of therapeutic complement inhibition, where proximal inhibitors (either anti-C3, anti-FD or anti-FB) may prove effective for the treatment of PNH, either in monotherapy or in combination with anti-C5 agents, eventually leading to drastic improvement of hematological response. (frontiersin.org)
  • In this review we discuss current evidence that complement activation contributes to progression of CKD, how complement could cause renal inflammation and whether complement inhibition would slow progression of renal disease. (wjgnet.com)
  • 1 Most recently, a drug from Genentech/Roche known as FCFD4514S (lampalizumab) provided the first evidence that the growth of GA could be slowed down by complement inhibition. (mvrf.org)
  • Considering the destructive potential of the complement system, it is no surprise that nearly half of the system's proteins are involved in its inhibition. (lu.se)
  • Dysregulation of the complement system has been implicated in several diseases and pathologies, including Atypical hemolytic uremic syndrome in which kidney function is compromised. (wikipedia.org)
  • The role of complement dysregulation on vascular endothelial cells has been well established in atypical hemolytic uremic syndrome (aHUS), a thrombotic microangiopathy (TMA) characterized by microangiopathic hemolytic anemia, thrombocytopenia, and target organ injury. (jrheum.org)
  • aHUS is a condition associated with alternative pathway complement dysregulation. (asn-online.org)
  • Alterations in the alternative pathway, like properdin or ficolin deficiency, increase the susceptibility to infection. (eaglebio.com)
  • occurs by three pathways: the classical pathway, the lectin pathway, and the alternative pathway (or properdin system). (britannica.com)
  • Finally, we have determined for the first time that the physiological forms of human properdin can selectively recognize surfaces and enhance or promote complement activation, which is in agreement with the reported role for properdin as a complement initiator. (utoledo.edu)
  • Alternative pathway components are often lettered (eg, factor B, factor D) or named (eg, properdin). (msdmanuals.com)
  • This pathway is regulated by properdin, factor H, and decay-accelerating factor (CD55). (msdmanuals.com)
  • The alternative pathway (AP) of complement consists of C3, factor B, factor D and properdin, which amplifies AP activation. (karger.com)
  • In this study, we investigated the role of properdin (P), a positive alternative pathway complement regulator, in allergen-induced airway inflammation. (nih.gov)
  • Properdin is a serum glycoprotein that up-regulates the alternative pathway of complement by stabilizing the C3b-Bb complex. (embl.de)
  • The alternative pathway is one of three complement pathways that opsonize and kill pathogens. (wikipedia.org)
  • But complement not only serve to eliminate pathogens, also contribute to other physiological surveillance functions. (hstalks.com)
  • The classical pathway is initiated by binding of C1q to antibody complexes, whereas the alternative and lectin pathway are activated in an antibody-independent fashion through the interaction of complement components with respectively specific carbohydrate groups and lipopolysaccharides (LPS) on the surface of foreign pathogens. (eaglebio.com)
  • and the alternative pathway, which is triggered by other means, including invading pathogens or tumour cells. (britannica.com)
  • 8 , 11 - 14 Numerous stimuli can drive the activation of the complement system, including apoptotic debris, pathogens, and antibody-antigen complexes, in addition to ischemia-reperfusion injuries associated with organ transplantation. (jrheum.org)
  • 4 , 13 Complement plays a crucial role in host defense against foreign bodies by promoting phagocyte-mediated clearance of cell debris through activation of an inflammatory response, opsonization of pathogens, and lysis of susceptible bacteria and cells. (jrheum.org)
  • However, only in recent years it has become apparent that complement not only plays a major role in innate defense against pathogens but also identifies foreign materials and removes waste (immune complexes and dying cells). (lu.se)
  • Invading pathogens activate complement either spontaneously due to differences in envelope/membrane composition compared to host (alternative and lectin pathways) or through antibody binding (classical pathway). (lu.se)
  • The classic and alternate pathway convertases cause C3 activation, forming C3a and C3b. (medscape.com)
  • Bb can then become the enzymatically active constituent of the C3 and C5 alternative pathway convertases. (quidel.com)
  • Most inhibitors act on complement convertases through increased dissociation of these enzymatic complexes (acceleration of decay) or through promoting enzymatic cleavage of activated complement factors C3b or C4b by a serine proteinase factor I (FI). (lu.se)
  • Alternative pathway activation also plays a significant role in complement-mediated renal disorders such as atypical hemolytic uremic syndrome, C3 glomerulopathy, and C3 glomerulonephritis (Dense Deposit Disease or MPGN Type II). (wikipedia.org)
  • 7 - 9 A TMA is called "primary" when a genetic or acquired defect in a complement protein is identified (as in atypical hemolytic uremic syndrome [aHUS]) or "secondary" when occurring in the context of another disease process or factor such as infection, autoimmune disease, malignancy, or drugs. (jrheum.org)
  • 3,4 LNP023 is currently in clinical development for PNH and a number of renal conditions with complement system involvement where significant unmet needs exist, including IgA nephropathy, complement 3 glomerulopathy (C3G), atypical hemolytic uremic syndrome and membranous nephropathy. (novartis.com)
  • Narsoplimab is also in multiple late-stage clinical development programs focused on other complement-mediated disorders, including IgA nephropathy, atypical hemolytic uremic syndrome and COVID-19. (biospace.com)
  • A common way to measure the activity of the classical or alternative pathway is the hemolysis of erythrocytes. (eaglebio.com)
  • Indeed, proximal inhibitors are designed to interfere with early phases of complement activation, eventually preventing C3-mediated extravascular hemolysis in addition to intravascular hemolysis. (frontiersin.org)
  • Paroxysmal nocturnal hemoglobinuria (PNH) is a rare hematological disorder characterized by complement-mediated intravascular hemolysis, bone marrow failure, and severe thrombophilia ( 1 ). (frontiersin.org)
  • PNH is a rare and life threatening blood disorder characterized by complement-driven hemolysis, thrombosis and impaired bone marrow function, 6 resulting in debilitating symptoms that can impact patient's quality of life. (novartis.com)
  • In PNH, LNP023 acts upstream of the C5 terminal pathway, preventing not only intravascular hemolysis but also extravascular hemolysis. (novartis.com)
  • PNH is a very rare, life-threatening and debilitating disease characterized by complement-mediated hemolysis with or without hemoglobinuria. (empr.com)
  • We have previously demonstrated that pathology in the smoke-induced ocular pathology (SIOP) model, a model with similarities to dry AMD, is dependent on activation of the alternative complement pathway and that a novel complement activation site targeted inhibitor of the alternative pathway can be delivered to ocular tissues via an adeno-associated virus (AAV). (marclab.org)
  • One can screen for deficiencies in complement by performing the total serum classic hemolytic complement (CH 50 ) test or the alternative hemolytic complement (AP 50 ) test. (medscape.com)
  • The alternative pathway is a type of cascade reaction of the complement system and is a component of the innate immune system, a natural defense against infections. (wikipedia.org)
  • The ELISA contains a positive control which can be used as control to ensure that the alternative complement cascade has run completely. (eaglebio.com)
  • C1 is the first molecule in the classical complement cascade and comprises C1q and two molecules of C1r and C1s respectively. (abcam.com)
  • The complement system is an enzyme cascade that helps defend against infection. (msdmanuals.com)
  • The "complement cascade" is a series of reactions that take place in the blood. (medlineplus.gov)
  • The cascade activates the complement proteins. (medlineplus.gov)
  • Pegcetacoplan is a synthetic cyclic peptide conjugated to a polyethylene glycol (PEG) polymer that inhibits the complement cascade centrally at C3. (empr.com)
  • According to Hantson, the clinical-stage Factor D inhibitor in Achillion's drug portfolio shows tremendous potential as its mechanism of action leaves intact the body's ability to fight infection and targets an alternative pathway of the complement activation cascade is inhibited. (yaledailynews.com)
  • The complement cascade is likely to play a major role in causing AMD. (mvrf.org)
  • It is therefore possible that inhibiting complement activation would reduce inflammation, lead to reduced fibrosis and preservation of renal function. (wjgnet.com)
  • the classical pathway initiated by antibodies bound to the surface of foreign bodies and the alternative and lectin pathways that provide an antibody-independent mechanism for complement activation, induced by the presence of bacteria and other micro-organisms. (abcam.com)
  • The classic pathway is activated by the interaction of C1 with an antigen-antibody complex. (medscape.com)
  • The CH 50 test specifically tests for deficiencies in the classic pathway by measuring the ability of the patient's serum to lyse antibody-coated sheep erythrocytes. (medscape.com)
  • Adipocytes synthesize factor D, the limiting component of the alternative complement pathway, which cleaves C3-bound factor B to its active enzymatic form. (medscape.com)
  • Complement activation proceeds in a sequential fashion through the proteolytic cleavage of a series of proteins leading to the generation of activated products that mediate various biological activities through their interaction with specific cellular receptors and other serum proteins. (eaglebio.com)
  • This cleavage activates the terminal complement pathway leading to eventually the formation of the terminal C5b-9 complement complex (TCC). (eaglebio.com)
  • Following these cleavage events, complement pathway activation continues as in the classical pathway. (abcam.com)
  • C3 cleavage may result in formation of the membrane attack complex (MAC), the cytotoxic component of the complement system. (msdmanuals.com)
  • Apoptotic pathways in ischemic acute renal failure. (bmj.com)
  • Functional complement C1q abnormality leads to impaired immune complexes and apoptotic cell clearance. (medscape.com)
  • C4b-binding protein (C4BP) is the major soluble inhibitor of the classical and lectin pathways whereas factor H (FH) inhibits the alternative route. (lu.se)
  • Complement deficiencies or other defects in the complement system can easily be screened by running an assay for each pathway in parallel or separately. (eaglebio.com)
  • Ram S. Complement and deficiencies. (medlineplus.gov)
  • Patients with classic complement pathway deficiencies should be screened for sequelae of immune complex diseases. (medscape.com)
  • Grumach AS, Kirschfink M. Are complement deficiencies really rare? (medscape.com)
  • Complement deficiencies in systemic lupus erythematosus. (medscape.com)
  • Complement genetics, deficiencies, and disease associations. (medscape.com)
  • The Mouse Alternative Complement Pathway ELISA Assay Kit is a qualitative/ semiquantitative ELISA to be used for the in vitro determination of activation of the alternative pathway of the complement system in serum and plasma samples. (eaglebio.com)
  • A major component of this response is the complement system. (eaglebio.com)
  • The complement system consist of a complex family of proteins and receptors which are found in the circulation, in tissues and other body-fluids. (eaglebio.com)
  • The system consist of three defined pathways which are activated by a pathway specific panel of molecules. (eaglebio.com)
  • Under certain conditions, the complement system can be unfavorable to the host leading to e.g. autoimmune diseases and infections. (eaglebio.com)
  • Binding of complement component C3 and Factor B to Cryptococcus neoformans serotypes A through D via the alternative complement pathway was measured in a system containing fresh nonimmune human serum. (johnshopkins.edu)
  • Purpose: The risk for age-related macular degeneration has been tied to an overactive complement system. (marclab.org)
  • The complement system is a heat-labile component of blood that confers bactericidal properties. (abcam.com)
  • The normal complement system consists of the classic and alternative pathways. (medscape.com)
  • The complement system is an integral part of the innate immune system but also augments adaptive immune responses. (wjgnet.com)
  • The complement system is a tightly regulated, cascading protein network representing a key component linking the innate and humoral immune systems. (jrheum.org)
  • Therefore, a clearer understanding of the role of the complement system in TMA associated with other conditions will help to identify patients who would benefit from these therapies. (jrheum.org)
  • The complement system is a tightly regulated, cascading protein network that performs multiple roles in homeostasis and disease prevention and is a key component of both the innate and the humoral immune systems. (jrheum.org)
  • Activation of the complement system occurs through the classical (CP), lectin (LP), or alternative (AP) pathways. (jrheum.org)
  • The complement system is a group of nearly 60 proteins that are in blood plasma or on the surface of some cells. (medlineplus.gov)
  • Total complement activity (CH50, CH100) looks at the overall activity of the complement system. (medlineplus.gov)
  • We will continue to develop LNP023 in this condition while exploring its use in a range of other diseases with complement system involvement. (novartis.com)
  • The two companies develop rare-disease therapeutics that target a specific immune pathway called the complement system. (yaledailynews.com)
  • The Achillion acquisition will expand Alexion's portfolio of drugs targeting the complement system, as two of Achillion's two clinical-stage medicines target complement-mediated rare diseases through a mechanism different from that of Alexion's existing drugs. (yaledailynews.com)
  • John Orloff, head of research and development at Alexion, added that targeting the alternative pathway of the complement system has significant opportunities for treating a broad range of rare diseases that have little or no existing treatments. (yaledailynews.com)
  • We have established great momentum - discovering and advancing several small molecules into clinical development that have the potential to treat immune-related diseases associated with the alternative pathway of the complement system," said Achillion President and Chief Executive Officer Joe Truitt in an Oct. 16 press release. (yaledailynews.com)
  • C3 plays a central role in the activation of the complement system. (abcam.com)
  • This gene encodes a G-protein coupled receptor 1 family member involved in the complement system of the innate immune response. (antikoerper-online.de)
  • Degn SE, Jensenius JC, Thiel S. Disease-causing mutations in genes of the complement system. (medscape.com)
  • The molecular mechanisms behind the bacteria-induced formation of fibrinopeptides were investigated and shown to be triggered by the activation of the contact system, also known as the kallikrein/kinin system or the intrinsic pathway of coagulation. (lu.se)
  • Our group investigates the physiological regulation of human complement system as well as pathologic situations when this regulation fails. (lu.se)
  • Learn about the three pathways lead to complement activation and some of their key inhibitors. (abcam.com)
  • These two latter pathogenic mechanisms are the target of novel strategies of anti-complement treatments, which can be split into terminal and proximal complement inhibitors. (frontiersin.org)
  • Many novel terminal complement inhibitors are now in clinical development: they all target C5 (as eculizumab), potentially paralleling the efficacy and safety profile of eculizumab. (frontiersin.org)
  • Advancements in the understanding of the etiopathogenesis of aHUS paved the way for the successful development of anticomplement therapies (complement C5 inhibitors), which have revolutionized the treatment of aHUS. (jrheum.org)
  • The addition of [Achillion's] clinical-stage Factor D inhibitors that have the potential to advance the standard of care for rare, complement-mediated diseases provides an important opportunity to diversify our complement portfolio. (yaledailynews.com)
  • Several of these inhibitors circulate in blood whereas others are expressed on virtually all cells of the body to protect self-tissue from complement attack. (lu.se)
  • Age related macular degeneration (AMD) is now believed to be caused, at least in part, by complement overactivation in retinal tissues. (wikipedia.org)
  • The pathways that lead to fibrosis are not fully understood, although chronic non-resolving inflammation in the kidney is likely to drive the fibrotic response that occurs. (wjgnet.com)
  • Complement activation occurs in progressive chronic kidney disease and may contribute to the chronic inflammation that is characteristically found in the kidney. (wjgnet.com)
  • Bean KV, Massey D, Gupta G. Mediators of inflammation: complement. (medlineplus.gov)
  • Curcumin, a natural polyphenolic compound derived from turmeric (Curcuma longa L), has proven to be a modulator of multiple intercellular signalling pathways linked to inflammation, to proliferation, growth, invasion, drug sensitivity, angiogenesis and metastasis of cancer cells. (researchgate.net)
  • Omeros is an innovative biopharmaceutical company committed to discovering, developing and commercializing small-molecule and protein therapeutics for large-market and orphan indications targeting inflammation, immunologic diseases (e.g., complement-mediated diseases) and cancers. (biospace.com)
  • Studies have demonstrated a clear and unambiguous association between AMD and genes encoding complement proteins.This has led to strategies to inhibit complement activation by targeting complement proteins. (mvrf.org)
  • The three pathways, designated classical, lectin and alternative pathway, converge at a central component into a final common pathway. (eaglebio.com)
  • The pathway is triggered when the C3b protein directly binds a microbe. (wikipedia.org)
  • CFHR5 (Complement Factor H-Related protein 5) is able to bind to act as a cofactor for factor I, has decay accelerating activity and is able to bind preferentially to C3b at host surfaces. (wikipedia.org)
  • Protein chemistry was used to assess complement activation, CR2-fH tissue distribution, and CR2-fH transport across the RPE. (marclab.org)
  • Factor H is a major plasma protein that plays a critical regulatory role in the alternative pathway of complement activation. (nih.gov)
  • Dried blood spot samples from newborns, which are already widely used in neonatal screening for selected metabolic diseases, may be employed in the future using reverse phase protein microarrays for determination of complement component C3 levels collected at birth. (medscape.com)
  • Some microorganisms either produce a functional mimic of a complement regulatory protein or hijack host's regulatory proteins. (lu.se)
  • gattii) bound approximately half as many molecules of both complement components as serotypes A and D (C. neoformans var. (johnshopkins.edu)
  • Adult worms possess surface molecules bearing alternative pathway complement activation sites ( Section 15.2.3.2 ), but these sites are masked by adsorbed host components in vivo [ 499 ]. (nanomedicine.com)
  • It may instead modulate signal transduction through the beta-arrestin pathway, and may alternatively act as a decoy receptor. (antikoerper-online.de)
  • Complement activation is known to occur in many diverse renal diseases, including glomerulonephritis, thrombotic microangiopathies and transplant rejection. (wjgnet.com)
  • Yet, a great deal of complexity exists around the role of complement in TMA associated with other diseases. (jrheum.org)
  • This review aims to provide an assessment of the nature and extent of complement involvement in TMA associated with autoimmune diseases such as systemic lupus erythematosus, antiphospholipid syndrome, and scleroderma renal crisis. (jrheum.org)
  • 10 This review aims to provide an assessment of the nature and extent of complement involvement in the underlying pathophysiology of TMA associated with autoimmune diseases that will help to stratify patients for targeted therapy. (jrheum.org)
  • Alexion has reported promising results of drugs that target diseases caused by abnormal complement activation, the immune system's mechanism for enhancing the ability to clear infectious agents and damaged cells from the body. (yaledailynews.com)
  • Alexion is an established leader in developing medicines for complement-mediated diseases, and we look forward to working together to accelerate our objective of bringing novel therapies to patients as quickly as possible and ensuring that the broad promise of this approach is fully realized. (yaledailynews.com)
  • The physiological relevance of complement is demonstrated by diseases affecting patients lacking complement components: recurrent infections, autoimmune diseases and glomerulonephritis. (lu.se)
  • Regrettably, uncontrolled complement activation also contributes significantly to pathology of many diseases (some examples: rheumatoid arthritis, ischemia/reperfusion injury, glomerulonephritis, multiple sclerosis, Alzheimer´s, hyperacute rejection of grafts) due to the fact that complement sometimes misdirects its activities towards own tissues. (lu.se)
  • Alternate pathway activation occurs when components of microbial cell surfaces (eg, yeast walls, bacterial cell wall lipopolysaccharide [endotoxin]) or immunoglobulin (eg, nephritic factor, aggregated IgA) cleave small amounts of C3. (msdmanuals.com)
  • Marks, R., Hindmarsh, E. Complement activation occurs on subendothelial extracelluslar matrix in vitro and is initiated by retraction or removal of overlying endothelial cells, J Immunol 160:6128-6136, 1998. (quidel.com)
  • A further complicating factor is the cross-talk between complement, neutrophils, and coagulation pathways in the pathophysiology of TMA. (jrheum.org)
  • The alternative pathway also acts as an amplification loop of the other pathways. (eaglebio.com)
  • When the alternative pathway is activated either directly or by the classical pathway via the amplification loop, C3b can bind whole Factor B. Factor D can then cleave Factor B in a single site to yield Ba and Bb. (quidel.com)
  • There are many of these Complement Polymorphisms that affect the functionality of the proteins encode by the genes. (hstalks.com)
  • Cees van Kooten Neutrophils and complement are key members of innate immunity. (karger.com)
  • Rarely, people may inherit deficiency of some complement proteins. (medlineplus.gov)
  • Skattum L, van Deuren M, van der Poll T, Truedsson L. Complement deficiency states and associated infections. (medscape.com)
  • Arnold DF, Roberts AG, Thomas A, Ferry B, Morgan BP, Chapel H. A novel mutation in a patient with a deficiency of the eighth component of complement associated with recurrent meningococcal meningitis. (medscape.com)
  • C5 Complement Deficiency in a Saudi Family, Molecular Characterization of Mutation and Literature Review. (medscape.com)
  • Complement C4 deficiency--a plausible risk factor for non-tuberculous mycobacteria (NTM) infection in apparently immunocompetent patients. (medscape.com)
  • The top scored pathway was " complement activation , alternative pathway", and several proteins involved in this pathway were down-regulated at 6 weeks. (bvsalud.org)
  • Lipodystrophy is often associated with glomerulonephritis, low C3 serum complement levels, and the presence of a C3 nephritic factor. (medscape.com)
  • Direct measurement of individual serum complement proteins, such as C3 and C4, can also be performed and is helpful in determining the diagnosis. (medscape.com)
  • Peerschke EI, Yin W, Alpert DR, Roubey RA, Salmon JE, Ghebrehiwet B. Serum complement activation on heterologous platelets is associated with arterial thrombosis in patients with systemic lupus erythematosus and antiphospholipid antibodies. (medscape.com)
  • C3 nephritic factor induces the lysis of adipocytes that secrete adipsin, a product identical to complement factor D. The distribution of the lipoatrophy is postulated to be dictated by the variable amounts of adipsin secreted by the adipocytes at different locations. (medscape.com)
  • Classical complement pathway Lectin pathway Conrad DH, Carlo JR, Ruddy S (June 1978). (wikipedia.org)
  • APL-1030 is thermostable, binds C3 (KD, 1.59 nM) and C3b (KD, 1.11 nM), and inhibits complement activation via classical (IC50 = 110.8 nM) and alternative (IC50 = 291.3 nM) pathways in Wieslab assays. (affilogic.com)
  • The term alternative is something of a misnomer because this pathway almost certainly evolved before the classical pathway. (britannica.com)
  • Classical pathway components are labeled with a C and a number (eg, C1, C3), based on the order in which they were identified. (msdmanuals.com)
  • This pathway otherwise resembles the classical pathway structurally and functionally. (msdmanuals.com)
  • It effectively blocks all 3 pathways of complement activation (classical, lectin, and alternative). (empr.com)
  • Complement is a crucial element of our innate immunity to fight infection. (hstalks.com)
  • Alternative pathway Computational simulation IRAK-M NFĸB Innate immunity Signaling Journal of Innate. (karger.com)
  • Purified human complement Factor B. Factor B is one of the proteins unique to the Alternative Complement Pathway. (quidel.com)
  • Quidel's purified human complement components are useful in a wide variety of immunochemical and research applications. (quidel.com)
  • note = "Meeting abstract from 13th European Meeting on Complement in Human Disease. (bath.ac.uk)
  • Furthermore some assays have been described to measure the activity of the MBL pathway. (eaglebio.com)
  • Omeros' lead MASP-2 inhibitor narsoplimab targets the lectin pathway of complement and is the subject of a biologics license application pending before FDA for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy. (biospace.com)
  • In vitro, bound complement is localized to infoldings of the parasite's tegument and not on its free surfaces [ 499 ]. (nanomedicine.com)
  • Inefficient binding of alternative pathway complement components to serotypes B and C may contribute to the relative difficulty in successfully treating infections caused by these organisms. (johnshopkins.edu)
  • People with some bacterial blood infections and shock often have very low C3 and components of what's known as the alternative pathway. (medlineplus.gov)
  • Complement factor H preferentially binds to vertebrate cells (because of affinity for sialic acid residues), allowing preferential protection of host (as opposed to bacterial) cells from complement-mediated damage. (wikipedia.org)
  • Mannose binding lectin (MBL), a major component of the lectin pathway, is associated with bacterial, fungal and viral infection. (eaglebio.com)
  • The inflammatory response to bacterial infection is the result of a complex interplay between bacterial products and host effector systems, such as the immune and complement systems. (lu.se)
  • The functions of complement include the attraction of inflammatory cells, opsonization to promote phagocytosis, immune complex clearance and direct microbial killing through the formation of the membrane attack complex (MAC). (abcam.com)
  • In vitro activation of the alternative pathway of complement by settled grain dust. (cdc.gov)