Complement c5 convertase classical pathway. Medical search

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.

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.

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.

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 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.

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 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 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).

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.

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.

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.

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).

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.

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.

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.

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.

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.

A serine endopeptidase that has specificity for cleavage at ARGININE. It cleaves a variety of prohormones including PRO-OPIOMELANOCORTIN, proluteinizing-hormone-releasing hormone, proenkephalins, prodynorphin, and PROINSULIN.

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.

A CALCIUM-dependent endopeptidase that has specificity for cleavage at ARGININE that is near paired basic residues. It cleaves a variety of prohormones including PRO-OPIOMELANOCORTIN; PRORENIN; proenkephalins; prodynorphin; prosomatostatin; and PROINSULIN.

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 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 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.

A serine protease that cleaves multiple COMPLEMENT 5 into COMPLEMENT 5A (anaphylatoxin) and COMPLEMENT 5B in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It is a complex of CLASSICAL PATHWAY C3 CONVERTASE (C4b2a) with an additional COMPLEMENT C3B, or C4b2a3b.

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).

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.

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 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.

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 serine protease that cleaves multiple COMPLEMENT 3 into COMPLEMENT 3A (anaphylatoxin) and COMPLEMENT 3B in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It is a complex of COMPLEMENT 4B and COMPLEMENT 2A (C4b2a).

A serine endopeptidase found primarily in the EXTRACELLULAR MATRIX. It has specificity for cleavage of a variety of substrates including PRORENIN, pro-membrane type-1 matrix metalloproteinase, and NEURAL CELL ADHESION MOLECULE L1.

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.

Proteolytic enzymes that are involved in the conversion of protein precursors such as peptide prohormones into PEPTIDE HORMONES. Some are ENDOPEPTIDASES, some are EXOPEPTIDASES.

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.

The COOH-terminal fragment of COMPLEMENT 2, released by the action of activated COMPLEMENT C1S. It is a SERINE PROTEASE. C2a combines with COMPLEMENT C4B to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).

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.

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.

The N-terminal fragment of COMPLEMENT 2, released by the action of activated COMPLEMENT C1S.

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.

Serum proteins that inhibit, antagonize, or inactivate COMPLEMENT C1 or its subunits.

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).

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).

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.

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.

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.

The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.

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.

An IgG autoantibody against the ALTERNATIVE PATHWAY C3 CONVERTASE, found in serum of patients with MESANGIOCAPILLARY GLOMERULONEPHRITIS. The binding of this autoantibody to C3bBb stabilizes the enzyme thus reduces the actions of C3b inactivators (COMPLEMENT FACTOR H; COMPLEMENT FACTOR I). This abnormally stabilized enzyme induces a continuous COMPLEMENT ACTIVATION and generation of C3b thereby promoting the assembly of MEMBRANE ATTACK COMPLEX and cytolysis.

Important enzymes in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. They cleave COMPLEMENT C3 and COMPLEMENT C5.

A family of SERINE ENDOPEPTIDASES isolated from Bacillus subtilis. EC 3.4.21.-

A proprotein convertase with specificity for the proproteins of PROALBUMIN; COMPLEMENT 3C; and VON WILLEBRAND FACTOR. It has specificity for cleavage near paired ARGININE residues that are separated by two amino acids.

Compounds that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host.

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.

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.

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.

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 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.

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.

The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.

A G-protein-coupled receptor that signals an increase in intracellular calcium in response to the potent ANAPHYLATOXIN peptide COMPLEMENT C5A.

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.

An acidic protein found in the NEUROENDOCRINE SYSTEM that functions as a molecular chaperone for PROPROTEIN CONVERTASE 2.

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.

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.

Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.

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)

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.

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.

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 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 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.

The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).

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 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 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.

A ZINC-containing exopeptidase primarily found in SECRETORY VESICLES of endocrine and neuroendocrine cells. It catalyzes the cleavage of C-terminal ARGININE or LYSINE residues from polypeptides and is active in processing precursors of PEPTIDE HORMONES and other bioactive peptides.

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.

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.

Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.

Abnormal immunoglobulins, especially IGG or IGM, that precipitate spontaneously when SERUM is cooled below 37 degrees Celsius. It is characteristic of CRYOGLOBULINEMIA.

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.

Polysaccharides consisting of mannose units.

Proteins prepared by recombinant DNA technology.

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.

A specific immune response elicited by a specific dose of an immunologically active substance or cell in an organism, tissue, or cell.

A serine protease that cleaves multiple COMPLEMENT C5 into COMPLEMENT C5A (anaphylatoxin) and COMPLEMENT C5B in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. It is the complex of ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb) with an additional COMPLEMENT C3B, or C3bBb3b.

Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.

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.

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.

The parts of a macromolecule that directly participate in its specific combination with another molecule.

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.

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.

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.

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.

Antibodies produced by a single clone of cells.

The rate dynamics in chemical or physical systems.

The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.

An adrenal microsomal cytochrome P450 enzyme that catalyzes the 21-hydroxylation of steroids in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP21 gene, converts progesterones to precursors of adrenal steroid hormones (CORTICOSTERONE; HYDROCORTISONE). Defects in CYP21 cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL).

Established cell cultures that have the potential to propagate indefinitely.

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.

Important enzymes in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. They cleave COMPLEMENT C3 and COMPLEMENT C5.

Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.

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.

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.

Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.

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.

A 19-kDa cationic peptide found in EOSINOPHIL granules. Eosinophil-derived neurotoxin is a RIBONUCLEASE and may play a role as an endogenous antiviral agent.

Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.

Transport proteins that carry specific substances in the blood or across cell membranes.

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).

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

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.

Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.

Immunoglobulins produced in a response to BACTERIAL ANTIGENS.

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.

Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.

Physiologically inactive substances that can be converted to active enzymes.

A sub-subclass of endopeptidases that depend on an ASPARTIC ACID residue for their activity.

Hormones secreted by the PITUITARY GLAND including those from the anterior lobe (adenohypophysis), the posterior lobe (neurohypophysis), and the ill-defined intermediate lobe. Structurally, they include small peptides, proteins, and glycoproteins. They are under the regulation of neural signals (NEUROTRANSMITTERS) or neuroendocrine signals (HYPOTHALAMIC HORMONES) from the hypothalamus as well as feedback from their targets such as ADRENAL CORTEX HORMONES; ANDROGENS; ESTROGENS.

A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.

The sum of the weight of all the atoms in a molecule.

The common precursor polypeptide of pancreatic GLUCAGON and intestinal GLUCAGON-LIKE PEPTIDES. Proglucagon is the 158-amino acid segment of preproglucagon without the N-terminal signal sequence. Proglucagon is expressed in the PANCREAS; INTESTINES; and the CENTRAL NERVOUS SYSTEM. Posttranslational processing of proglucagon is tissue-specific yielding numerous bioactive peptides.

A 66-kDa peroxidase found in EOSINOPHIL granules. Eosinophil peroxidase is a cationic protein with a pI of 10.8 and is comprised of a heavy chain subunit and a light chain subunit. It possesses cytotoxic activity towards BACTERIA and other organisms, which is attributed to its peroxidase activity.

A 30-kDa protein synthesized primarily in the ANTERIOR PITUITARY GLAND and the HYPOTHALAMUS. It is also found in the skin and other peripheral tissues. Depending on species and tissues, POMC is cleaved by PROHORMONE CONVERTASES yielding various active peptides including ACTH; BETA-LIPOTROPIN; ENDORPHINS; MELANOCYTE-STIMULATING HORMONES; and others (GAMMA-LPH; CORTICOTROPIN-LIKE INTERMEDIATE LOBE PEPTIDE; N-terminal peptide of POMC or NPP).

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)

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.

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 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.

Proteins isolated from the outer membrane of Gram-negative bacteria.

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 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.

A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.

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.

ENDOPEPTIDASES which use a metal such as ZINC in the catalytic mechanism.

Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.

A plasma protein that circulates in increased amounts during inflammation and after tissue damage.

The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.

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.

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.

Proteins found in any species of bacterium.

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.

A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.

The clear portion of BLOOD that is left after BLOOD COAGULATION to remove BLOOD CELLS and clotting proteins.

The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.

A 69-amino acid peptide derived from the N-terminal of PROGLUCAGON. It is mainly produced by the INTESTINAL L CELLS. Further processing of glicentin yield a 30-amino acid N-terminal peptide (glicentin-related polypeptide) and a 37-amino acid peptide OXYNTOMODULIN. Both glicentin and oxyntomodulin can reduce digestive secretions and delay gastric emptying.

Substances elaborated by bacteria that have antigenic activity.

Enzymes that act at a free C-terminus of a polypeptide to liberate a single amino acid residue.

A genus of trematode flukes belonging to the family Schistosomatidae. There are over a dozen species. These parasites are found in man and other mammals. Snails are the intermediate hosts.

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 serine endopeptidase isolated from Bacillus subtilis. It hydrolyzes proteins with broad specificity for peptide bonds, and a preference for a large uncharged residue in P1. It also hydrolyzes peptide amides. (From Enzyme Nomenclature, 1992) EC 3.4.21.62.

The relationship between the dose of an administered drug and the response of the organism to the drug.

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.

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.

Thickening of the walls of small ARTERIES or ARTERIOLES due to cell proliferation or HYALINE deposition.

The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.

The genetic region which contains the loci of genes which determine the structure of the serologically defined (SD) and lymphocyte-defined (LD) TRANSPLANTATION ANTIGENS, genes which control the structure of the IMMUNE RESPONSE-ASSOCIATED ANTIGENS, HUMAN; the IMMUNE RESPONSE GENES which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement.

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 subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.

Receptors on the plasma membrane of nonhepatic cells that specifically bind LDL. The receptors are localized in specialized regions called coated pits. Hypercholesteremia is caused by an allelic genetic defect of three types: 1, receptors do not bind to LDL; 2, there is reduced binding of LDL; and 3, there is normal binding but no internalization of LDL. In consequence, entry of cholesterol esters into the cell is impaired and the intracellular feedback by cholesterol on 3-hydroxy-3-methylglutaryl CoA reductase is lacking.

A condition characterized by the recurrence of HEMOGLOBINURIA caused by intravascular HEMOLYSIS. In cases occurring upon cold exposure (paroxysmal cold hemoglobinuria), usually after infections, there is a circulating antibody which is also a cold hemolysin. In cases occurring during or after sleep (paroxysmal nocturnal hemoglobinuria), the clonal hematopoietic stem cells exhibit a global deficiency of cell membrane proteins.

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.

Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.

In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.

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.

Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.

The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.

Elements of limited time intervals, contributing to particular results or situations.

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.

A family of membrane-anchored glycoproteins that contain a disintegrin and metalloprotease domain. They are responsible for the proteolytic cleavage of many transmembrane proteins and the release of their extracellular domain.

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.)

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 phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.

Glycoproteins found on the membrane or surface of cells.

Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.

A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).

The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.

Histochemical localization of immunoreactive substances using labeled antibodies as reagents.

A 37-amino acid peptide derived from the C-terminal of GLICENTIN. It is mainly produced by the INTESTINAL L CELLS. Oxyntomodulin can reduce digestive secretions, delay gastric emptying, and reduced food intake.

Cleavage of proteins into smaller peptides or amino acids either by PROTEASES or non-enzymatically (e.g., Hydrolysis). It does not include Protein Processing, Post-Translational.

Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.

Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides A and B, the proteolytic action of other enzymes yields different fibrinogen degradation products.

Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.

Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.

The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.

Plasma glycoprotein member of the serpin superfamily which inhibits TRYPSIN; NEUTROPHIL ELASTASE; and other PROTEOLYTIC ENZYMES.

Plasma glycoproteins that form a stable complex with hemoglobin to aid the recycling of heme iron. They are encoded in man by a gene on the short arm of chromosome 16.

A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.

Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).

Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.

A di-isopropyl-fluorophosphate which is an irreversible cholinesterase inhibitor used to investigate the NERVOUS SYSTEM.

The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.

The process of cleaving a chemical compound by the addition of a molecule of water.

A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.

Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).

Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.

Glomerulonephritis associated with autoimmune disease SYSTEMIC LUPUS ERYTHEMATOSUS. Lupus nephritis is histologically classified into 6 classes: class I - normal glomeruli, class II - pure mesangial alterations, class III - focal segmental glomerulonephritis, class IV - diffuse glomerulonephritis, class V - diffuse membranous glomerulonephritis, and class VI - advanced sclerosing glomerulonephritis (The World Health Organization classification 1982).

Autoantibody stabilization of the classical pathway C3 convertase leading to C3 deficiency and Neisserial sepsis: C4 nephritic factor revisited. (1/1)

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There are two main types of hemolysis:

1. Intravascular hemolysis: This type occurs within the blood vessels and is caused by factors such as mechanical injury, oxidative stress, and certain infections.
2. Extravascular hemolysis: This type occurs outside the blood vessels and is caused by factors such as bone marrow disorders, splenic rupture, and certain medications.

Hemolytic anemia is a condition that occurs when there is excessive hemolysis of RBCs, leading to a decrease in the number of healthy red blood cells in the body. This can cause symptoms such as fatigue, weakness, pale skin, and shortness of breath.

Some common causes of hemolysis include:

1. Genetic disorders such as sickle cell anemia and thalassemia.
2. Autoimmune disorders such as autoimmune hemolytic anemia (AIHA).
3. Infections such as malaria, babesiosis, and toxoplasmosis.
4. Medications such as antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and blood thinners.
5. Bone marrow disorders such as aplastic anemia and myelofibrosis.
6. Splenic rupture or surgical removal of the spleen.
7. Mechanical injury to the blood vessels.

Diagnosis of hemolysis is based on a combination of physical examination, medical history, and laboratory tests such as complete blood count (CBC), blood smear examination, and direct Coombs test. Treatment depends on the underlying cause and may include supportive care, blood transfusions, and medications to suppress the immune system or prevent infection.

The term "systemic" refers to the fact that the disease affects multiple organ systems, including the skin, joints, kidneys, lungs, and nervous system. LES is a complex condition, and its symptoms can vary widely depending on which organs are affected. Common symptoms include fatigue, fever, joint pain, rashes, and swelling in the extremities.

There are several subtypes of LES, including:

1. Systemic lupus erythematosus (SLE): This is the most common form of the disease, and it can affect anyone, regardless of age or gender.
2. Discoid lupus erythematosus (DLE): This subtype typically affects the skin, causing a red, scaly rash that does not go away.
3. Drug-induced lupus erythematosus: This form of the disease is caused by certain medications, and it usually resolves once the medication is stopped.
4. Neonatal lupus erythematosus: This rare condition affects newborn babies of mothers with SLE, and it can cause liver and heart problems.

There is no cure for LES, but treatment options are available to manage the symptoms and prevent flares. Treatment may include nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, immunosuppressive medications, and antimalarial drugs. In severe cases, hospitalization may be necessary to monitor and treat the disease.

It is important for people with LES to work closely with their healthcare providers to manage their condition and prevent complications. With proper treatment and self-care, many people with LES can lead active and fulfilling lives.

The symptoms of glomerulonephritis can vary depending on the underlying cause of the disease, but may include:

* Blood in the urine (hematuria)
* Proteinuria (excess protein in the urine)
* Reduced kidney function
* Swelling in the legs and ankles (edema)
* High blood pressure

Glomerulonephritis can be caused by a variety of factors, including:

* Infections such as staphylococcal or streptococcal infections
* Autoimmune disorders such as lupus or rheumatoid arthritis
* Allergic reactions to certain medications
* Genetic defects
* Certain diseases such as diabetes, high blood pressure, and sickle cell anemia

The diagnosis of glomerulonephritis typically involves a physical examination, medical history, and laboratory tests such as urinalysis, blood tests, and kidney biopsy.

Treatment for glomerulonephritis depends on the underlying cause of the disease and may include:

* Antibiotics to treat infections
* Medications to reduce inflammation and swelling
* Diuretics to reduce fluid buildup in the body
* Immunosuppressive medications to suppress the immune system in cases of autoimmune disorders
* Dialysis in severe cases

The prognosis for glomerulonephritis depends on the underlying cause of the disease and the severity of the inflammation. In some cases, the disease may progress to end-stage renal disease, which requires dialysis or a kidney transplant. With proper treatment, however, many people with glomerulonephritis can experience a good outcome and maintain their kidney function over time.

Idiopathic membranous nephropathy (IMN) is an autoimmune disorder that causes GNM without any identifiable cause. Secondary membranous nephropathy, on the other hand, is caused by systemic diseases such as lupus or cancer.

The symptoms of GNM can vary depending on the severity of the disease and may include blood in the urine, proteinuria, edema, high blood pressure, and decreased kidney function. The diagnosis of GNM is based on a combination of clinical findings, laboratory tests, and renal biopsy.

Treatment for GNM is aimed at slowing the progression of the disease and managing symptoms. Medications such as corticosteroids, immunosuppressive drugs, and blood pressure-lowering drugs may be used to treat GNM. In some cases, kidney transplantation may be necessary.

The prognosis for GNM varies depending on the severity of the disease and the underlying cause. In general, the prognosis for IMN is better than for secondary membranous nephropathy. With proper treatment, some patients with GNM can experience a slowing or stabilization of the disease, while others may progress to end-stage renal disease (ESRD).

The cause of GNM is not fully understood, but it is believed to be an autoimmune disorder that leads to inflammation and damage to the glomerular membrane. Genetic factors and environmental triggers may also play a role in the development of GNM.

There are several risk factors for developing GNM, including family history, age (GMN is more common in adults), and certain medical conditions such as hypertension and diabetes.

The main complications of GNM include:

1. ESRD: Progression to ESRD is a common outcome of untreated GNM.
2. High blood pressure: GNM can lead to high blood pressure, which can further damage the kidneys.
3. Infections: GNM increases the risk of infections due to impaired immune function.
4. Kidney failure: GNM can cause chronic kidney failure, leading to the need for dialysis or a kidney transplant.
5. Cardiovascular disease: GNM is associated with an increased risk of cardiovascular disease, including heart attack and stroke.
6. Malnutrition: GNM can lead to malnutrition due to decreased appetite, nausea, and vomiting.
7. Bone disease: GNM can cause bone disease, including osteoporosis and bone pain.
8. Anemia: GNM can cause anemia, which can lead to fatigue, weakness, and shortness of breath.
9. Increased risk of infections: GNM increases the risk of infections due to impaired immune function.
10. Decreased quality of life: GNM can significantly decrease a person's quality of life, leading to decreased mobility, pain, and discomfort.

It is important for individuals with GNM to receive early diagnosis and appropriate treatment to prevent or delay the progression of these complications.

Arteriolosclerosis is often associated with conditions such as hypertension, diabetes, and atherosclerosis, which is the buildup of plaque in the arteries. It can also be caused by other factors such as smoking, high cholesterol levels, and inflammation.

The symptoms of arteriolosclerosis can vary depending on the location and severity of the condition, but may include:

* Decreased blood flow to organs or tissues
* Fatigue
* Weakness
* Shortness of breath
* Dizziness or lightheadedness
* Pain in the affected limbs or organs

Arteriolosclerosis is typically diagnosed through a combination of physical examination, medical history, and diagnostic tests such as ultrasound, angiography, or blood tests. Treatment for the condition may include lifestyle changes such as exercise and dietary modifications, medications to control risk factors such as hypertension and high cholesterol, and in some cases, surgical intervention to open or bypass blocked arterioles.

In summary, arteriolosclerosis is a condition where the arterioles become narrowed or obstructed, leading to decreased blood flow to organs and tissues and potentially causing a range of health problems. It is often associated with other conditions such as hypertension and atherosclerosis, and can be diagnosed through a combination of physical examination, medical history, and diagnostic tests. Treatment may include lifestyle changes and medications to control risk factors, as well as surgical intervention in some cases.

The disorder is caused by mutations in the HBB gene that codes for the beta-globin subunit of hemoglobin. These mutations result in the production of abnormal hemoglobins that are unstable and prone to breakdown, leading to the release of free hemoglobin into the urine.

HP is classified into two types based on the severity of symptoms:

1. Type 1 HP: This is the most common form of the disorder and is characterized by mild to moderate anemia, occasional hemoglobinuria, and a normal life expectancy.
2. Type 2 HP: This is a more severe form of the disorder and is characterized by severe anemia, recurrent hemoglobinuria, and a shorter life expectancy.

There is no cure for HP, but treatment options are available to manage symptoms and prevent complications. These may include blood transfusions, folic acid supplements, and medications to reduce the frequency and severity of hemoglobinuria episodes.

1) They share similarities with humans: Many animal species share similar biological and physiological characteristics with humans, making them useful for studying human diseases. For example, mice and rats are often used to study diseases such as diabetes, heart disease, and cancer because they have similar metabolic and cardiovascular systems to humans.

2) They can be genetically manipulated: Animal disease models can be genetically engineered to develop specific diseases or to model human genetic disorders. This allows researchers to study the progression of the disease and test potential treatments in a controlled environment.

3) They can be used to test drugs and therapies: Before new drugs or therapies are tested in humans, they are often first tested in animal models of disease. This allows researchers to assess the safety and efficacy of the treatment before moving on to human clinical trials.

4) They can provide insights into disease mechanisms: Studying disease models in animals can provide valuable insights into the underlying mechanisms of a particular disease. This information can then be used to develop new treatments or improve existing ones.

5) Reduces the need for human testing: Using animal disease models reduces the need for human testing, which can be time-consuming, expensive, and ethically challenging. However, it is important to note that animal models are not perfect substitutes for human subjects, and results obtained from animal studies may not always translate to humans.

6) They can be used to study infectious diseases: Animal disease models can be used to study infectious diseases such as HIV, TB, and malaria. These models allow researchers to understand how the disease is transmitted, how it progresses, and how it responds to treatment.

7) They can be used to study complex diseases: Animal disease models can be used to study complex diseases such as cancer, diabetes, and heart disease. These models allow researchers to understand the underlying mechanisms of the disease and test potential treatments.

8) They are cost-effective: Animal disease models are often less expensive than human clinical trials, making them a cost-effective way to conduct research.

9) They can be used to study drug delivery: Animal disease models can be used to study drug delivery and pharmacokinetics, which is important for developing new drugs and drug delivery systems.

10) They can be used to study aging: Animal disease models can be used to study the aging process and age-related diseases such as Alzheimer's and Parkinson's. This allows researchers to understand how aging contributes to disease and develop potential treatments.

There are several types of lupus nephritis, each with its own unique characteristics and symptoms. The most common forms include:

* Class I (mesangial proliferative glomerulonephritis): This type is characterized by the growth of abnormal cells in the glomeruli (blood-filtering units of the kidneys).
* Class II (active lupus nephritis): This type is characterized by widespread inflammation and damage to the kidneys, with or without the presence of antibodies.
* Class III (focal lupus nephritis): This type is characterized by localized inflammation in certain areas of the kidneys.
* Class IV (lupus nephritis with crescentic glomerulonephritis): This type is characterized by widespread inflammation and damage to the kidneys, with crescent-shaped tissue growth in the glomeruli.
* Class V (lupus nephritis with sclerotic changes): This type is characterized by hardening and shrinkage of the glomeruli due to scarring.

Lupus Nephritis can cause a range of symptoms, including:

* Proteinuria (excess protein in the urine)
* Hematuria (blood in the urine)
* Reduced kidney function
* Swelling (edema)
* Fatigue
* Fever
* Joint pain

Lupus Nephritis can be diagnosed through a combination of physical examination, medical history, laboratory tests, and kidney biopsy. Treatment options for lupus nephritis include medications to suppress the immune system, control inflammation, and prevent further damage to the kidneys. In severe cases, dialysis or a kidney transplant may be necessary.

Nephritis is often diagnosed through a combination of physical examination, medical history, and laboratory tests such as urinalysis and blood tests. Treatment for nephritis depends on the underlying cause, but may include antibiotics, corticosteroids, and immunosuppressive medications. In severe cases, dialysis may be necessary to remove waste products from the blood.

Some common types of nephritis include:

1. Acute pyelonephritis: This is a type of bacterial infection that affects the kidneys and can cause sudden and severe symptoms.
2. Chronic pyelonephritis: This is a type of inflammation that occurs over a longer period of time, often as a result of recurrent infections or other underlying conditions.
3. Lupus nephritis: This is a type of inflammation that occurs in people with systemic lupus erythematosus (SLE), an autoimmune disorder that can affect multiple organs.
4. IgA nephropathy: This is a type of inflammation that occurs when an antibody called immunoglobulin A (IgA) deposits in the kidneys and causes damage.
5. Mesangial proliferative glomerulonephritis: This is a type of inflammation that affects the mesangium, a layer of tissue in the kidney that helps to filter waste products from the blood.
6. Minimal change disease: This is a type of nephrotic syndrome (a group of symptoms that include proteinuria, or excess protein in the urine) that is caused by inflammation and changes in the glomeruli, the tiny blood vessels in the kidneys that filter waste products from the blood.
7. Membranous nephropathy: This is a type of inflammation that occurs when there is an abnormal buildup of antibodies called immunoglobulin G (IgG) in the glomeruli, leading to damage to the kidneys.
8. Focal segmental glomerulosclerosis: This is a type of inflammation that affects one or more segments of the glomeruli, leading to scarring and loss of function.
9. Post-infectious glomerulonephritis: This is a type of inflammation that occurs after an infection, such as streptococcal infections, and can cause damage to the kidneys.
10. Acute tubular necrosis (ATN): This is a type of inflammation that occurs when there is a sudden loss of blood flow to the kidneys, causing damage to the tubules, which are tiny tubes in the kidneys that help to filter waste products from the blood.

There are several key features of inflammation:

1. Increased blood flow: Blood vessels in the affected area dilate, allowing more blood to flow into the tissue and bringing with it immune cells, nutrients, and other signaling molecules.
2. Leukocyte migration: White blood cells, such as neutrophils and monocytes, migrate towards the site of inflammation in response to chemical signals.
3. Release of mediators: Inflammatory mediators, such as cytokines and chemokines, are released by immune cells and other cells in the affected tissue. These molecules help to coordinate the immune response and attract more immune cells to the site of inflammation.
4. Activation of immune cells: Immune cells, such as macrophages and T cells, become activated and start to phagocytose (engulf) pathogens or damaged tissue.
5. Increased heat production: Inflammation can cause an increase in metabolic activity in the affected tissue, leading to increased heat production.
6. Redness and swelling: Increased blood flow and leakiness of blood vessels can cause redness and swelling in the affected area.
7. Pain: Inflammation can cause pain through the activation of nociceptors (pain-sensing neurons) and the release of pro-inflammatory mediators.

Inflammation can be acute or chronic. Acute inflammation is a short-term response to injury or infection, which helps to resolve the issue quickly. Chronic inflammation is a long-term response that can cause ongoing damage and diseases such as arthritis, asthma, and cancer.

There are several types of inflammation, including:

1. Acute inflammation: A short-term response to injury or infection.
2. Chronic inflammation: A long-term response that can cause ongoing damage and diseases.
3. Autoimmune inflammation: An inappropriate immune response against the body's own tissues.
4. Allergic inflammation: An immune response to a harmless substance, such as pollen or dust mites.
5. Parasitic inflammation: An immune response to parasites, such as worms or fungi.
6. Bacterial inflammation: An immune response to bacteria.
7. Viral inflammation: An immune response to viruses.
8. Fungal inflammation: An immune response to fungi.

There are several ways to reduce inflammation, including:

1. Medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and disease-modifying anti-rheumatic drugs (DMARDs).
2. Lifestyle changes, such as a healthy diet, regular exercise, stress management, and getting enough sleep.
3. Alternative therapies, such as acupuncture, herbal supplements, and mind-body practices.
4. Addressing underlying conditions, such as hormonal imbalances, gut health issues, and chronic infections.
5. Using anti-inflammatory compounds found in certain foods, such as omega-3 fatty acids, turmeric, and ginger.

It's important to note that chronic inflammation can lead to a range of health problems, including:

1. Arthritis
2. Diabetes
3. Heart disease
4. Cancer
5. Alzheimer's disease
6. Parkinson's disease
7. Autoimmune disorders, such as lupus and rheumatoid arthritis.

Therefore, it's important to manage inflammation effectively to prevent these complications and improve overall health and well-being.

There are three main forms of ACH:

1. Classic congenital adrenal hyperplasia (CAH): This is the most common form of ACH, accounting for about 90% of cases. It is caused by mutations in the CYP21 gene, which codes for an enzyme that converts cholesterol into cortisol and aldosterone.
2. Non-classic CAH (NCAH): This form of ACH is less common than classic CAH and is caused by mutations in other genes involved in cortisol and aldosterone production.
3. Mineralocorticoid excess (MOE) or glucocorticoid deficiency (GD): These are rare forms of ACH that are characterized by excessive production of mineralocorticoids (such as aldosterone) or a deficiency of glucocorticoids (such as cortisol).

The symptoms of ACH can vary depending on the specific form of the disorder and the age at which it is diagnosed. In classic CAH, symptoms typically appear in infancy and may include:

* Premature puberty (in girls) or delayed puberty (in boys)
* Abnormal growth patterns
* Distended abdomen
* Fatigue
* Weight gain or obesity
* Easy bruising or bleeding

In NCAH and MOE/GD, symptoms may be less severe or may not appear until later in childhood or adulthood. They may include:

* High blood pressure
* Low blood sugar (hypoglycemia)
* Weight gain or obesity
* Fatigue
* Mood changes

If left untreated, ACH can lead to serious complications, including:

* Adrenal gland insufficiency
* Heart problems
* Bone health problems
* Increased risk of infections
* Mental health issues (such as depression or anxiety)

Treatment for ACH typically involves hormone replacement therapy to restore the balance of hormones in the body. This may involve taking medications such as cortisol, aldosterone, or other hormones to replace those that are deficient or imbalanced. In some cases, surgery may be necessary to remove an adrenal tumor or to correct physical abnormalities.

With proper treatment, many individuals with ACH can lead healthy, active lives. However, it is important for individuals with ACH to work closely with their healthcare providers to manage their condition and prevent complications. This may involve regular check-ups, hormone level monitoring, and lifestyle changes such as a healthy diet and regular exercise.

The condition is caused by mutations in the genes that code for proteins involved in cholesterol transport and metabolism, such as the low-density lipoprotein receptor gene (LDLR) or the PCSK9 gene. These mutations lead to a decrease in the ability of the liver to remove excess cholesterol from the bloodstream, resulting in high levels of LDL cholesterol and low levels of HDL cholesterol.

Hyperlipoproteinemia type II is usually inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is enough to cause the condition. However, some cases can be caused by spontaneous mutations or incomplete penetrance, where not all individuals with the mutated gene develop the condition.

Symptoms of hyperlipoproteinemia type II can include xanthomas (yellowish deposits of cholesterol in the skin), corneal arcus (a white, waxy deposit on the iris of the eye), and tendon xanthomas (small, soft deposits of cholesterol under the skin). Treatment typically involves a combination of dietary changes and medication to lower LDL cholesterol levels and increase HDL cholesterol levels. In severe cases, liver transplantation may be necessary.

Hyperlipoproteinemia type II is a serious condition that can lead to cardiovascular disease, including heart attacks, strokes, and peripheral artery disease. Early diagnosis and treatment are important to prevent or delay the progression of the disease and reduce the risk of complications.

... two regulators of complement. The membrane attack complex is initiated when the complement protein C5 convertase cleaves C5 ... 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+ ...

https://en.wikipedia.org/wiki/Complement_membrane_attack_complex

After the creation of C5 convertase (either as (C3b)2BbP or C4b2a3b from the classical pathway), the complement system follows ... a stable compound which can bind an additional C3b to form alternative pathway C5-convertase. The C5-convertase of the ... The alternative pathway is one of three complement pathways that opsonize and kill pathogens. The pathway is triggered when the ... This complex is also known as a fluid-phase C3-convertase. This convertase, the alternative pathway C3-convertase, although ...

https://en.wikipedia.org/wiki/Alternative_complement_pathway

The classical pathway C5 convertase is composed of the fragments of complement proteins, C4b, C2a produced by cleavage mediated ... The target of C5 convertase is complement protein C5. C5 is a two-chain (α, β) plasma glycoprotein (Mr = 196,000). C5 and C3 ... The complement component C5 can be also activated by fluid phase C5 convertase. C5 is activated by CVFBb in the presence of ... or the alternative pathway (C3bBbC3b) of complement system. Two fluid phase C5 convertases have been described: the classical ...

https://en.wikipedia.org/wiki/C5-convertase

... classical-complement-pathway C3/C5 convertase EC 3.4.21.44: Now EC 3.4.21.43, classical-complement-pathway C3/C5 convertase EC ... classical-complement-pathway C3/C5 convertase EC 3.4.21.44: Now EC 3.4.21.43, classical-complement-pathway C3/C5 convertase EC ... 3.4.21.45: complement factor I EC 3.4.21.46: complement factor D EC 3.4.21.47: alternative-complement-pathway C3/C5 convertase ... 3.4.21.45: complement factor I EC 3.4.21.46: complement factor D EC 3.4.21.47: alternative-complement-pathway C3/C5 convertase ...

https://en.wikipedia.org/wiki/List_of_EC_numbers_(EC_3)

C3b binds to the C3 convertase (C4b2b), to form C5 convertase (C4b2b3b). C5 convertase then cleaves C5 into C5a and C5b. Like ... Alternative complement pathway - another complement system pathway Lectin pathway - another complement system pathway Noris, ... The classical complement pathway is one of three pathways which activate the complement system, which is part of the immune ... Activation of the complement pathway through the classical, lectin or alternative complement pathway is followed by a cascade ...

https://en.wikipedia.org/wiki/Classical_complement_pathway

It is a membrane protein and regulates also C5 convertase of the classical and alternative pathway. DAF protects host cells ... the classical, lectin, and alternative pathways. Cleavage of complement C3 by a free floating convertase, thrombin, plasmin or ... C3 convertase can be used to refer to the form produced in the alternative pathway (C3bBb) or the classical and lectin pathways ... "Formation of classical C3 convertase during the alternative pathway of human complement activation". Biokhimiia (Moscow, Russia ...

https://en.wikipedia.org/wiki/C3-convertase

In the classical and lectin pathways of complement activation, formation of the C3-convertase and C5-convertases requires ... The protein encoded by this gene is part of the classical pathway of the complement system, acting as a multi-domain serine ... C2b is the smallest , enzymatically active, fragment of C3 convertase in this pathway, C4b2b (NB: some sources now refer to the ... a fragment of complement component C2 produced during C3 convertase formation". Acta Crystallographica D. 65 (Pt 3): 266-274. ...

https://en.wikipedia.org/wiki/Complement_component_2

... iC3b C5 - C5a C3-convertase C5-convertase Late stage Membrane attack complex (MAC) C6 C7 C8 C9 Complement pathway inhibitors C1 ... system Complement system Classical complement pathway Mannan-binding lectin pathway Alternate complement pathway Complement ... divided by pathway) Classical complement pathway C1Q complex - C1R / C1S C4 - C4a C2 Mannan-binding lectin pathway MASP1 / ... Classical, Lectin, Alternate Decay-accelerating factor (CD59) - Classical, Lectin, Alternate Factor I - Classical, Lectin, ...

https://en.wikipedia.org/wiki/Outline_of_immunology

The complex of C3b(2)Bb is a protease which cleaves C5 into C5b and C5a. C5 convertase is also formed by the classical pathway ... Three biochemical pathways activate the complement system: the classical complement pathway, the alternative complement pathway ... The three pathways of activation all generate homologous variants of the protease C3-convertase. The classical complement ... C4b and C2b then bind together to form the classical C3-convertase, as in the classical pathway. Ficolins are homologous to MBL ...

https://en.wikipedia.org/wiki/Complement_system

... classical pathway, alternative pathway and lectin pathway) that ultimately lead to the formation of a C3 convertase. Formation ... In such cases treatment with the complement-inhibitory anti-C5 monoclonal antibody, eculizumab, is found to be highly effective ... In the classical pathway, the microbial pathogen is coated in antibodies (IgG and IgM) released by B cells. The C1 complement ... Additionally, C3b plays a role in forming a C3 convertase when bound to Factor B (C3bBb complex), or a C5 convertase when bound ...

https://en.wikipedia.org/wiki/C3b

... participates in all three of the complement pathways (classical, alternative, and lectin); the alternative pathway is " ... C5 binding sites, 4) private allelic residues. Additionally, the same study identified the expression of human complement C4 ... the C4b-C2a complex with protease activity has been termed the C3 convertase. Protein 4b can be further cleaved into 4c and 4d ... In the classical pathway, the complement component-hereafter abbreviated by the "C" preceding the protein number- termed C1s, a ...

https://en.wikipedia.org/wiki/Complement_component_4

Antibodies can also trigger the classical pathway - one of the three pathways of the complement cascade. Briefly, the C1 ... pathogens and bind to C3 convertase to catalyze the formation of C5 convertase to produce C5a and C5b for terminal complement ... The formation of complement proteins (C3a, C3b, C5a, C5b, etc.) ultimately congregates into a membrane-attack complex to lyse ... In addition to the generation of complement proteins, C1 complex also induces the activation of B cells, monocytes, macrophages ...

https://en.wikipedia.org/wiki/Passive_antibody_therapy

... complement c3-c5 convertases, classical pathway MeSH D12.776.124.486.274.860.387.750.500 - complement c3 convertase, classical ... complement c3-c5 convertases MeSH D12.776.124.486.274.860.387.500 - complement c3-c5 convertases, alternative pathway MeSH ... complement c3 convertase, alternative pathway MeSH D12.776.124.486.274.860.387.500.750 - complement c5 convertase, alternative ... pathway MeSH D12.776.124.486.274.860.387.750.750 - complement c5 convertase, classical pathway MeSH D12.776.124.486.274.860. ...

https://en.wikipedia.org/wiki/List_of_MeSH_codes_(D12.776.124)

MASP2 and initiate the lectin pathway of complement activation which is somewhat similar to the classical complement pathway. ... C3 is cleaved into its a and b subunits, and C3b binds the convertase. These together are called the C5 convertase. Similarly ... dependent signaling pathway. MyD88 - dependent pathway is induced by various PAMPs stimulating the TLRs on macrophages and ... dependent pathway and triggers the signaling through NF-κB and the MAP kinase pathway and therefore the secretion of pro- ...

https://en.wikipedia.org/wiki/Pattern_recognition_receptor

classical-complement-pathway C3/C5 convertase complex CoA-synthesizing protein complex CSK-GAP-A.p62 complex ... Pathways Community Rat Community Forum Directory of Rat Laboratories Video Tutorials News RGD Publications RGD Poster Archive ...

https://rgd.mcw.edu/rgdweb/ontology/view.html?acc_id=GO:1903293

Complement C3-C5 Convertases, Classical Pathway [D12.776.124.486.274.045.387.750] * Complement C3 Convertase, Classical Pathway ... C5 Convertase (C4b2a3b) Classical C5 Convertase Classical Pathway C5 Convertase Pharm Action. Immunologic Factors. Registry ... and COMPLEMENT 5B in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It is a complex of CLASSICAL PATHWAY C3 CONVERTASE (C4b2a) ... and COMPLEMENT 5B in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It is a complex of CLASSICAL PATHWAY C3 CONVERTASE (C4b2a) ...

https://meshb-prev.nlm.nih.gov/record/ui?ui=D051577

Complement C3-C5 Convertases, Classical Pathway [D12.776.124.486.274.045.387.750] * Complement C3 Convertase, Classical Pathway ... They cleave COMPLEMENT C3 and COMPLEMENT C5.. Terms. Complement C3-C5 Convertases, Classical Pathway Preferred Term Term UI ... They cleave COMPLEMENT C3 and COMPLEMENT C5.. Entry Term(s). Classical Pathway C3-C5 Convertases Pharm Action. Immunologic ... Complement C3-C5 Convertases [D12.776.124.486.274.045.387] * Complement C3-C5 Convertases, Alternative Pathway [D12.776.124.486 ...

https://meshb-prev.nlm.nih.gov/record/ui?ui=D050579

Site 1 (CCPs 1-3) alone mediated the decay acceleration of the classical and alternative pathway C3 convertases. Site 2 (CCPs 8 ... Site 1 (CCPs 1-3) alone mediated the decay acceleration of the classical and alternative pathway C3 convertases. Site 2 (CCPs 8 ... Site 1 (CCPs 1-3) alone mediated the decay acceleration of the classical and alternative pathway C3 convertases. Site 2 (CCPs 8 ... Site 1 (CCPs 1-3) alone mediated the decay acceleration of the classical and alternative pathway C3 convertases. Site 2 (CCPs 8 ...

https://profiles.wustl.edu/en/publications/decay-accelerating-activity-of-complement-receptor-type-1-cd35-tw

Complement C5 Convertase, Classical Pathway Entry term(s). C5 Convertase (C4b2a3b) C5 Convertase, Classical Classical C5 ... Classical pathway C5 convertase Entry term(s):. C5 Convertase (C4b2a3b). C5 Convertase, Classical. Classical C5 Convertase. ... Complement C3-C5 Convertases, Classical Pathway [D12.776.124.486.274.045.387.750] Complement C3-C5 Convertases, Classical ... Complement C5 Convertase, Classical Pathway Descriptor Spanish: C5 Convertasa de la Vía Clásica del Complemento Spanish from ...

https://decs.bvsalud.org/en/ths/resource/?id=50834

The C2 gene provides instructions for making the complement component 2 protein. Learn about this gene and related health ... Complement component C2, inhibiting a latent serine protease in the classical pathway of complement activation. Biochemistry. ... C3/C5 convertase. *CO2. *complement component 2. *complement component C2. Additional Information & Resources. Tests Listed in ... Without this protein to form C3 convertase, activation of the complement system is stalled. As a result, the complement ...

https://medlineplus.gov/genetics/gene/c2/

... of the FHRs with pentraxins resulted in enhanced activation of both the classical and the alternative complement pathways on ... of the FHRs with pentraxins resulted in enhanced activation of both the classical and the alternative complement pathways on ... Factor H (FH), a major soluble complement inhibitor, binds to dead cells and inhibits excessive complement activation on their ... Factor H (FH), a major soluble complement inhibitor, binds to dead cells and inhibits excessive complement activation on their ...

https://www.frontiersin.org/articles/10.3389/fimmu.2020.01297/full

The complement system plays an important part in defense against pyogenic organisms. ... The complement system is part of the innate immune system. ... The pathways include the classical pathway (C1qrs, C2, C4), the ... C5 Complement Deficiency in a Saudi Family, Molecular Characterization of Mutation and Literature Review. J Clin Immunol. 2013 ... the proteins factor H and factor I inhibit the formation of the enzyme C3 convertase of the alternative pathway. Similarly, the ...

http://emedicine.medscape.com/article/886128-overview

No deposition of C4b, as part of the classical and lectin pathway convertases, was detected on trypanosomes. We present the ... although terminal pathway inhibition via C5 blockade can effectively inhibit hemolysis, proximal complement inhibition with ... We describe the discovery of SAR443809, a specific inhibitor of the alternative pathway C3/C5 convertase (C3bBb). SAR443809 ... takes over a role in selective inhibition of the alternative pathway C5 convertase and thus abrogation of the terminal pathway ...

https://pesquisa.bvsalud.org/nicaragua/?lang=es&q=mh:Complemento+C3/metabolismo

The C3 and C5 convertases are enzymatic complexes that initiate and amplify the activity of the complement pathways and ... There are three pathways of complement activation. The classical pathway (CP) is initiated by Immune complexes; the lectin ... Each generates a C3 convertase, a serine protease that cleaves the central complement protein C3, and generates the major ... The complement system plays important roles in both innate and adaptive immune response. and can produce an inflammatory and ...

https://eaglebio.com/product/c1-inh-elisa-assay-kit/

Complement C3-C5 Convertases, Alternative Pathway [D12.776.124.486.274.045.387.500] * Complement C3-C5 Convertases, Classical ... They cleave COMPLEMENT C4 and COMPLEMENT C2 to form C4b2a, the CLASSICAL PATHWAY C3 CONVERTASE.. Terms. Mannose-Binding Protein ... They cleave COMPLEMENT C4 and COMPLEMENT C2 to form C4b2a, the CLASSICAL PATHWAY C3 CONVERTASE.. Entry Term(s). MASP MASP ... Complement Activating Enzymes [D12.776.124.486.274.045] * Complement C3-C5 Convertases [D12.776.124.486.274.045.387] * ...

https://meshb.nlm.nih.gov/record/ui?ui=D050606

Role of the C3b-binding site on C4b-binding protein in regulating classical pathway C5 convertase. Mol Immunol 2007;44:1105- ... The complement system is mainly composed of the classical, lectin, and alternate pathway and serves an important role in both ... Further studies that include various markers of the classical complement pathway or inflammatory markers, such as CRP and ... is a major soluble inhibitor and second regulator of both the classical and lectin complement pathways [9,19]. In addition to ...

https://www.psychiatryinvestigation.org/journal/view.php?number=1501

Activation of complement via the classical pathway Classical pathway Complement activation initiated by the binding of ... and the subsequent C5 convertase (c4b2a3b) leading to cleavage of complement C5 and the assembly of complement membrane attack ... Activated C1s cleaves complement C4 and complement C2 forming the membrane-bound classical C3 convertase (c4b2a) ... This leads to the sequential activation of complement C1r and complement C1s subunits. ...

https://www.lecturio.com/concepts/hypersensitivity-pneumonitis/

C3 convertases cleave C3 into C3a and C3b. C3b permits the formation of C5 convertase. C3b has further functions in ... the mannose-binding lectin (MBL) pathway. Subsequent cleavage and assembly of C2 and C4 proteins form the C3 convertase. The ... Complement depletion decreases antibody production (18) through antigen-bound C3dg binding to CR2 (CD21). This facilitates ... a protease inhibitor of the serpin superfamily that inhibits the classical and LPs by binding and inactivating C1r, C1s, MASP-1 ...

http://www.baxkyardgardener.com/category/cyclooxygenase/

C5 Convertase, Classical use Complement C5 Convertase, Classical Pathway C5 Convertases, Complement use Complement C3-C5 ... C5 Convertase (C4b2a3b) use Complement C5 Convertase, Classical Pathway C5 Convertase, Alternative Pathway use Complement C5 ... C3 Convertase, Classical use Complement C3 Convertase, Classical Pathway C3 Convertases, Complement use Complement C3-C5 ... C3 Convertase (C3bBb) use Complement C3 Convertase, Alternative Pathway C3 Convertase (C4b2a) use Complement C3 Convertase, ...

https://decs.bvs.br/I/DeCS2017_Alfab-C.htm

... a monoclonal antibody targeted against complement C5, inhibits activation of the alternative complement pathway. We could not ... MPGN can be classified into either immunoglobulin (IgG)-associated MPGN (caused by classical complement pathway activation); ... In affected patients, the alternative pathway produces C3 convertase, which amplifies C3 activation, resulting in the creation ... is a monoclonal antibody targeted against complement C5 that inhibits the activation of the alternative complement pathway. ...

https://chikd.org/journal/view.php?number=675&viewtype=pubreader

Sialidase treated human c2 and c5 increase hemolytic activity of the classical complement pathway. FASEB Journal 2(6): Abstract ... Sialidase treated c2 increases the catalytic property of the classical pathway c3 convertase. Complement 4(3-4): 222 ... Hirsch, R.L.; Griffin, D.E.; Winkelstein, J.A. 1981: Sialic acid influences alternative complement pathway activation by ... Kliot, M.; Shatz, C.J. 1981: Siamese cat pre natal development of the retino geniculate pathway. IOVS Investigative ...

https://eurekamag.com/research/029/159/

CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).. ... The larger fragment C3b binds with C3 convertase to form C5 convertase.. ... Complement C3. 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 ...

https://lookformedical.com/en/search/anti-glomerular-basement-membrane-disease

These pathways differ activated for the osmolyte of multiple histones into inflammation( Sutterlin et al. This distinct ... also, a C3bBb3b download data mining and predictive procaspases and this enhances a C5 v-src. WTX is a cancer of the freeze- ... The Resection of Nef is coil and classical diet of the activity aminoacyl CD4. SNF variants BRG1 and ISWI and Members of the ... as the setting complements a private immunoglobulin( Nelson & Eisenberg 2006). When download data mining photoreceptors in the ...

http://evakoch.com/books/download-data-mining-and-predictive-analysis-intelligence-gathering-and-crime-analysis-2015.php

Formation of high affinity C5 convertase of the classical pathway of complement.. Rawal N; Pangburn MK. J Biol Chem; 2003 Oct; ... The conversion of human complement component C5 into fragment C5b by the alternative-pathway C5 convertase.. DiScipio RG. ... 1. Alternative pathway of complement: recruitment of precursor properdin by the labile C3/C5 convertase and the potentiation of ... 7. C3 requirements for formation of alternative pathway C5 convertase.. Daha MR; Fearon DT; Austen KF. J Immunol; 1976 Aug; 117 ...

https://pubmedhh.nlm.nih.gov/biomarkers/search.php?id=978134&mod=related&page=1&outid=&proj=

... that provides catalytic activity for the C3 and C5 convertases of the classical and lectin pathways of human complement. The ... formation of these convertases requires the Mg(2+)-dependent binding of C2 to C4b and the subsequent … ... The second component of complement (C2) is a multi-domain serine protease ... The crystal structure of C2a, the catalytic fragment of classical pathway C3 and C5 convertase of human complement. Krishnan V ...

https://pubmed.ncbi.nlm.nih.gov/19237749

https://meshb.nlm.nih.gov/record/ui?ui=D051577

Classical Pathway C3 C5 Convertases Classical Pathway C3-C5 Convertases Complement C3 C5 Convertases, Classical Pathway ... Classical Pathway C3 C5 Convertases. Classical Pathway C3-C5 Convertases. Complement C3 C5 Convertases, Classical Pathway. ... Complement C3-C5 Convertases, Classical Pathway [D12.776.124.486.274.045.387.750] Complement C3-C5 Convertases, Classical ... Complement C3-C5 Convertases, Alternative Pathway [D12.776.124.486.274.045.387.500] Complement C3-C5 Convertases, Alternative ...

https://decs.bvsalud.org/en/ths/resource/?id=50832

The absence of two glycosylphosphatidylinositol (GPI)-anchored proteins, CD55 and CD59, leads to uncontrolled complement ... Complement regulation and eculizumab. The lectin, classical, and alternative pathways converge at the point of C3 activation. ... CD55 inhibits proximal complement activation by blocking the formation of C3 convertases; CD59 inhibits terminal complement ... Terminal complement begins with cleavage of C5 to C5a and C5b. C5b oligomerizes with C6, C7, C8, and multiple C9 molecules to ...

https://www.ncbi.nlm.nih.gov/pubmed/25237200

The complement system can be activated in three ways: via the classical pathway, the alternative pathway or the mannose binding ... a C3 convertase is formed, which subsequently cleaves C3, which in turn cleaves C5, activating the final common pathway. ... classical and MBL pathways] or C3bBb [alternative pathway]), which cleaves C3. The resulting C3b cleaves C5 and activates a ... IgM or IgG immune complexes activate the classical pathway. The alternative pathway is constitutively active but held in check ...

https://www.medscape.com/viewarticle/762699_3

C2a, a serine protease, then combines with complement factor C4b to generate the C3 or C5 convertase. Component C2 is a serum ... glycoprotein that functions as part of the classical pathway of the complement system. Activated C1 cleaves C2 into C2a and C2b ... The serine proteinase C2a then combines with complement factor 4b to create the C3 or C5 convertase. Deficiency of C2 has been ... Component C2 which is part of the classical pathway of the complement system is cleaved by activated factor C1 into two ...

https://pharos.nih.gov/targets/C2

This gene encodes the acidic form of complement factor 4, part of the classical activation pathway. The protein is expressed as ... The trimer provides a surface for interaction between the antigen-antibody complex and other complement components. The alpha ... Derived from proteolytic degradation of complement C4, C4a anaphylatoxin is a mediator of local inflammatory process. It ... Non-enzymatic component of C3 and C5 convertases and thus essential for the propagation of the classical complement pathway. ...

https://pharos.ncats.nih.gov/targets/C4A

They cleave COMPLEMENT C3 and COMPLEMENT C5. HN - 2006 MH - Complement C3-C5 Convertases, Classical Pathway UI - D050579 MN - ... CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE). HN - 2006 (1986) MH - Complement C2b ... CONVERTASE (C3bBb) with an additional COMPLEMENT C3B, or C3bBb3b. HN - 2006 MH - Complement C5 Convertase, Classical Pathway UI ... hydrolyzes the COMPLEMENT C4B in the CLASSICAL PATHWAY C3 CONVERTASE (C4bC2a). HN - 2006 MH - Complement C5 Convertase, ...

https://nlmpubs.nlm.nih.gov/projects/mesh/.newterms/.bkup/mshnew2006.10-03-2005.txt

... revealing a targetable mechanistic difference between the classical and alternative pathway C5 convertases. Taking a hybrid ... was found to reduce the activity of complement C5 in some pathways, whilst leaving other pathways intact. This could ... and complement system-related genes [complement component 5 (c5), complement component 7a (c7a), mannan-binding lectin serine ... with one peptide selectively inhibiting C5 cleavage by the alternative pathway C5 convertase, ...

https://pesquisa.bvsalud.org/portal/?lang=pt&q=mh:Complemento+C5/metabolismo

Alternative Pathway N0000169299 Complement C5 Convertase, Classical Pathway N0000169288 Complement C5a N0000169289 Complement ... Classical Pathway N0000169359 Complement C3 Nephritic Factor N0000169293 Complement C3-C5 Convertases N0000169294 Complement C3 ... C5 Convertases, Alternative Pathway N0000169298 Complement C3-C5 Convertases, Classical Pathway N0000169287 Complement C3a ... Complement C4b N0000169308 Complement C4b-Binding Protein N0000169274 Complement C5 N0000169296 Complement C5 Convertase, ...

https://evs.nci.nih.gov/ftp1/FDA/ndfrt/Archive/StructuralClass%202012-06-04.txt

Complement System and Immunology; Allergic Disorders - Learn about from the MSD Manuals - Medical Professional Version. ... The classical, lectin, and alternative pathways converge into a final common pathway when C3 convertase (C3 con) cleaves C3 ... Deficiency of C5, C9, factor B, factor D, or properdin: Susceptibility to neisserial infections Meningococcal Diseases ... There are 3 pathways of complement activation (see figure Complement activation pathways Complement activation pathways ): ...

https://www.msdmanuals.com/professional/immunology-allergic-disorders/biology-of-the-immune-system/complement-system

https://emedicine.staging.medscape.com/article/135478-overview

Complement C3-C5 Convertases Complement C3-C5 Convertases, Alternative Pathway Complement C3-C5 Convertases, Classical Pathway ... Complement C5 Convertase, Classical Pathway Complement C5a Complement C5a, des-Arginine Complement C5b Complement C6 Complement ... Complement C4a Complement C4b Complement C4b-Binding Protein Complement C5 Complement C5 Convertase, Alternative Pathway TERM ... Complement C2a Complement C2b Complement C3 Complement C3 Convertase, Alternative Pathway Complement C3 Convertase, Classical ...

https://nlmpubs.nlm.nih.gov/projects/mesh/.newterms/mshd2017.txt

Involved in the RCC1/Ran-GTPase pathway. Involved in the RCC1/Ran-GTPase pathway. May play a direct role in a TNF-alpha ... May be able to complement the 26S proteasome function to some extent under conditions in which the latter is inhibited (By ... This involves the isomerization of uridine such that the ribose is subsequently attached to C5, instead of the normal N1. Each ... 062119 1.51 proprotein convertase subtilisin/kexin type 7 precursor Pcsk7 Rattus norvegicus Likely to represent a ubiquitous ...

https://esbl.nhlbi.nih.gov/helixweb/Database/Transcriptomic/images/ThickAscLimbData.txt

Site 1 (CCPs 1-3) alone mediated the decay acceleration of the classical and alternative pathway C3 convertases. (wustl.edu)
Properdin can bind C3b and activate the alternative complement pathway and also stabilizes the C3bBb alternative pathway C3 convertase enzyme, thereby directing the deposition of C3 fragments to the cell surface and driving the amplification loop ( 17 - 19 ). (frontiersin.org)
The alternative pathway is activated in an antibody-independent manner. (medscape.com)
In affected patients, the alternative pathway produces C3 convertase, which amplifies C3 activation, resulting in the creation of C3b particles, and finally, the formation of C5 convertase to assemble MAC C5b-9. (chikd.org)

Based on these results, we generated proteins one-fourth the size of CR1 but with enhanced decay accelerating activity for the C3 convertases. (wustl.edu)
The complement system is a group of proteins that work together to destroy foreign invaders (such as bacteria and viruses), trigger inflammation, and remove debris from cells and tissues. (medlineplus.gov)
Together, these proteins form a complex called C3 convertase, which triggers further activation of the pathway, allowing the proteins of the complement system to participate in an immune response. (medlineplus.gov)
The FH-related (FHR) proteins share common ligands with FH, due to their homology with this complement regulator, but they lack the domains that mediate the complement inhibitory activity of FH. (frontiersin.org)
Genes that encode the proteins of complement components or their isotypes are distributed throughout different chromosomes, with 19 genes comprising 3 significant complement gene clusters in the human genome. (medscape.com)
The important components of this system are various cell membrane-associated proteins such as complement receptor 1 (CR1), complement receptor 2 (CR2), and decay accelerating factor (DAF). (medscape.com)
Background: The complement system is made up of an abundance of unique plasma proteins that play an important role in innate immunity and inflammation, aiding in the fight against pathogenic microbes and viral diseases. (bvsalud.org)
Factor H and other complement proteins regulate the amplification of C3 activation [ 8 ]. (chikd.org)

A serine protease that cleaves multiple COMPLEMENT 5 into COMPLEMENT 5A (anaphylatoxin) and COMPLEMENT 5B in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY . (nih.gov)
Complement component C2, inhibiting a latent serine protease in the classical pathway of complement activation. (medlineplus.gov)
Each generates a C3 convertase, a serine protease that cleaves the central complement protein C3, and generates the major cleavage fragment C3b. (eaglebio.com)
Serum serine proteases which participate in COMPLEMENT ACTIVATION . (nih.gov)

It is a complex of CLASSICAL PATHWAY C3 CONVERTASE (C4b2a) with an additional COMPLEMENT C3B , or C4b2a3b. (nih.gov)
They cleave COMPLEMENT C4 and COMPLEMENT C2 to form C4b2a, the CLASSICAL PATHWAY C3 CONVERTASE . (nih.gov)

Lectins activate the lectin pathway in a manner similar to the antibody interaction with complement in the classical pathway. (medscape.com)

Both FHRs caused increased complement activation on DNA. (frontiersin.org)

Factor H (FH), a major soluble complement inhibitor, binds to dead cells and inhibits excessive complement activation on their surface, preventing lysis, and the release of intracellular material, including DNA. (frontiersin.org)
C3G complement blockade with eculizumab, a monoclonal antibody targeted against complement C5, inhibits activation of the alternative complement pathway. (chikd.org)

New studies point to the complex interplay between the complement cascade and adaptive immune response, and complement is also being studied in association with ischemic injury as a target of therapy. (medscape.com)
The complement system plays important roles in both innate and adaptive immune response and can produce an inflammatory and protective reaction to challenges from pathogens before an adaptive response can occur. (eaglebio.com)

Without this protein to form C3 convertase, activation of the complement system is stalled. (medlineplus.gov)
Because their roles in complement regulation is controversial and incompletely understood, we studied the interaction of FHR-1 and FHR-5 with DNA and dead cells and investigated whether they influence the regulatory role of FH and the complement activation on DNA and dead cells. (frontiersin.org)
Interactions of the FHRs with pentraxins resulted in enhanced activation of both the classical and the alternative complement pathways on dead cells when exposed to human serum. (frontiersin.org)
Dying cells also expose ligands that bind initiator molecules of the various complement pathways, so that complement activation and opsonin deposition on the dead cell surface may enhance phagocytotic clearance ( 1 , 8 ). (frontiersin.org)
Notably, these pentraxins may also recruit soluble complement regulators, such as factor H (FH) and C4b-binding protein (C4BP), which in turn limit excessive complement activation on the surface ( 11 - 14 ). (frontiersin.org)
at the same time, the inflammation promoted by complement activation can result in cellular damage when not kept in check. (medscape.com)
Complement factor H (CFH) negatively regulates consumption of complement component 3 (C3), thereby restricting complement activation. (bvsalud.org)
There are three pathways of complement activation. (eaglebio.com)
As a result the activation of the complement system is blocked. (eaglebio.com)
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. (lookformedical.com)

CONCLUSION: Patients with a post-COVID-19 condition showed significantly increased immunological parameters of inflammation (complement factor C3 and CD8 and Th1 T lymphocyte populations) compared to fully recovered patients. (bvsalud.org)
The complement system is mainly composed of the classical, lectin, and alternate pathway and serves an important role in both inflammation and innate immunity. (psychiatryinvestigation.org)
In fact, many previous studies have shown the role of complement in central nervous system (CNS) [ 11 - 13 ], and alteration of complement components has been suggested to contribute to the pathogenesis of depression by participating in inflammation [ 14 - 16 ]. (psychiatryinvestigation.org)

Deficiencies in complement predispose patients to infection via 2 mechanisms: (1) ineffective opsonization and (2) defects in lytic activity (defects in MAC). (medscape.com)

In addition to playing an important role in host defense against infection, the complement system is a mediator in both the pathogenesis and prevention of immune complex diseases, such as systemic lupus erythematosus (SLE). (medscape.com)
Recently, new therapies have been suggested to target complement pathways, owing to an improvement in the understanding of the pathogenesis of C3G. (chikd.org)

An intricate system regulates complement activity. (medscape.com)

The purpose of this study was to evaluate the serum complement C4 concentration in COVID-19 patients in Khartoum and compare them to healthy controls. (bvsalud.org)

The goal of this study was to identify the site(s) in CR1 that mediate the dissociation of the C3 and C5 convertases. (wustl.edu)

The complement system is a key humoral component of innate immunity, and in addition to its many other functions, it is involved in the clearance of waste material, such as immune complexes and apoptotic and necrotic cells ( 1 , 2 ). (frontiersin.org)
The complement system is part of the innate immune system. (medscape.com)
Although the complement system is part of the body's innate, relatively nonspecific defense against pathogens, its role is hardly primitive or easily understood. (medscape.com)

Decay accelerating activity of complement receptor type 1 (CD35). (wustl.edu)
Dive into the research topics of 'Decay accelerating activity of complement receptor type 1 (CD35). (wustl.edu)

When a foreign invader is detected, the complement pathway is turned on (activated) and the complement component 2 protein attaches (binds) to a similar protein called complement component 4. (medlineplus.gov)

At least five mutations in the C2 gene have been found to cause complement component 2 deficiency. (medlineplus.gov)
More than 90 percent of people with complement component 2 deficiency have a mutation that deletes 28 DNA building blocks (nucleotides) from the C2 gene. (medlineplus.gov)
It is unclear how complement component 2 deficiency leads to increased susceptibility to autoimmune disorders. (medlineplus.gov)
It is likely that other factors, both genetic and environmental, play a role in the variability of the signs and symptoms of complement component 2 deficiency. (medlineplus.gov)
Cases of complement deficiency have helped defined the role of complement in host defense. (medscape.com)
A North African study of molecular basis of complement factor I deficiency in atypical hemolytic and uremic syndrome patients suggested that the Ile357Met mutation may be a founding effect. (medscape.com)

PCC patients showed significantly higher levels of complement factor C3 than fully recovered patients: median C3 128 mg/dL [p25-p75:107-135] vs 111 mg/dL [p25-p75: 100-125] (p =.005), respectively. (bvsalud.org)
Moreover, significantly higher levels of C1q, C3, C4, and C5 have been found in patients with MDD than in HC [ 14 - 18 ]. (psychiatryinvestigation.org)

The C2 gene provides instructions for making the complement component 2 protein. (medlineplus.gov)

Deficiencies in the complement cascade can lead to overwhelming infection and sepsis. (medscape.com)
The complement cascade consists of 3 separate pathways that converge in a final common pathway. (medscape.com)
The one-way ANOVA test showed no statistically significant differences between age categories in complement C4 level (P = 0.735) Conclusions: The case group had a higher mean level of complement C4 than the control group, which could be understood by the stimulation of the complement cascade during the COVID-19 illness. (bvsalud.org)

[ 2 ] , whereas C5 to C9 may have enhanced susceptibility to meningococcal disease. (medscape.com)

This mutation prevents the production of any complement component 2 protein. (medlineplus.gov)
C3GN also includes disease entities associated with complement mutation, which is causally associated with the underlying renal pathology, such as familial DDD with C3 mutation and familial C3GN with mutations in the CFHR genes. (chikd.org)

In contrast, for the C5 convertase, site 1 had only 0.5% of the decay accelerating activity, while site 2 had no detectable activity. (wustl.edu)
Efficient C5 decay accelerating activity was detected in recombinants that carried both site 1 and site 2. (wustl.edu)
The results indicate that, for the C5 convertases, decay accelerating activity is mediated primarily by site 1. (wustl.edu)

Alternatively, the dysfunctional complement system may perform partial attacks on invading molecules, which leaves behind foreign fragments that are difficult to distinguish from the body's tissues, so the complement system sometimes attacks the body's own cells. (medlineplus.gov)
Some new clinical entities are linked with partial complement defects. (medscape.com)

This article outlines some of the disease states associated with complement deficiencies and their clinical implications. (medscape.com)

This protein helps regulate a part of the body's immune response known as the complement system. (medlineplus.gov)

As a result, the complement system's ability to fight infections is diminished. (medlineplus.gov)

The initiator molecules of the classical (C1q) and lectin pathways (e.g. (frontiersin.org)

The C3 and C5 convertases are enzymatic complexes that initiate and amplify the activity of the complement pathways and ultimately generate the cytolytic MAC (C5b-9). (eaglebio.com)

multiple cross-links are organic in often all normal surfaces where they suffer acylated first pathways been on their G-protein download data mining and predictive analysis intelligence gathering and. (evakoch.com)

The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation. (medlineplus.gov)
These 3 pathways converge at the component C3. (medscape.com)

Furthermore, the complement C4 level in severe COVID-19 patients was lower than in non-severe COVID-19. (bvsalud.org)
Recently, plasma exchange/plasma infusion and provision of eculizumab, a monoclonal antibody against C5, can be used in cases of nephritic syndrome and/or decreased renal function in patients with C3GN. (chikd.org)

The complement system plays an important part in defense against pyogenic organisms. (medscape.com)

Complement plays an essential role in the opsonophagocytic clearance of apoptotic/necrotic cells. (frontiersin.org)

Results: The means level of complement C4 (mg/dL) were 37.44 ±18.618, 23.90 ±10.229 in the case group and in the control group, respectively. (bvsalud.org)

To that end, truncated derivatives of CR1 whose extracellular part is composed of 30 tandem repeating modules, termed complement control protein repeats (CCPs), were generated. (wustl.edu)
There was a statistically significant difference in complement C4 level between case and control (p-values ≤0.01). (bvsalud.org)

[ 4 ] A registry of complement deficiencies has been established as a means to promote joint projects on treatment and prevention of diseases associated with defective complement function. (medscape.com)

Anatomy19

Organisms12

Diseases12

Chemicals and Drugs136

Analytical, Diagnostic and Therapeutic Techniques and Equipment22

Phenomena and Processes43

Disciplines and Occupations1

Information Science3

Autoantibody stabilization of the classical pathway C3 convertase leading to C3 deficiency and Neisserial sepsis: C4 nephritic factor revisited. (1/1)

Complement Pathway, Classical

Complement C3

Complement C4

Complement Activation

Complement C1q

Complement C3-C5 Convertases

Complement C2

Complement C4b

Complement C3b

Complement Pathway, Alternative

Complement C4a

Complement System Proteins

Complement C5

Complement Activating Enzymes

Complement C3a

Complement Inactivator Proteins

Complement C1

Proprotein Convertase 2

Complement C5a

Proprotein Convertase 1

Complement Factor B

Complement C1s

Complement C6

Complement C5 Convertase, Classical Pathway

Complement C3d

Complement C3c

Receptors, Complement

Complement C9

Complement C1r

Complement C3 Convertase, Classical Pathway

Proprotein Convertase 5

Complement Membrane Attack Complex

Proprotein Convertases

Properdin

Complement C2a

Complement Factor D

Complement C7

Complement C2b

Complement C3 Convertase, Alternative Pathway

Complement C5b

Complement C1 Inactivator Proteins

Complement Factor H

Complement C4b-Binding Protein

Receptors, Complement 3b

Complement Hemolytic Activity Assay

Complement C3b Inactivator Proteins

Hemolysis

Complement Factor I

Complement C3 Nephritic Factor

Complement C3-C5 Convertases, Classical Pathway

Subtilisins

Furin

Complement Inactivating Agents

Antigens, CD55

Complement C8

Complement C1 Inhibitor Protein

Opsonin Proteins

Antigen-Antibody Complex

Complement Pathway, Mannose-Binding Lectin

Immunoglobulin G

Receptor, Anaphylatoxin C5a

Blood Bactericidal Activity

Neuroendocrine Secretory Protein 7B2

Complement Fixation Tests

Receptors, Complement 3d

Serine Endopeptidases

Antigens, CD59

Antigens, CD46

Anaphylatoxins

Molecular Sequence Data

Collectins

Mannose-Binding Lectin

Phagocytosis

Protein Binding

Amino Acid Sequence

Immunoglobulin M

Carboxypeptidase H

Cobra Venoms

Zymosan

Mannose-Binding Protein-Associated Serine Proteases