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 smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.Complement C4: 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.Complement C4a: 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.Complement C3a: 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.Complement C1q: A subcomponent of complement C1, composed of six copies of three polypeptide chains (A, B, and C), each encoded by a separate gene (C1QA; C1QB; C1QC). This complex is arranged in nine subunits (six disulfide-linked dimers of A and B, and three disulfide-linked homodimers of C). C1q has binding sites for antibodies (the heavy chain of IMMUNOGLOBULIN G or IMMUNOGLOBULIN M). The interaction of C1q and immunoglobulin activates the two proenzymes COMPLEMENT C1R and COMPLEMENT C1S, thus initiating the cascade of COMPLEMENT ACTIVATION via the CLASSICAL COMPLEMENT PATHWAY.Complement C5a: 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.Complement Activation: 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.Complement C4b: 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).Complement C5: 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.Complement C3b: 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 System Proteins: 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).Complement C6: 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.Complement C3c: 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.Complement C3d: 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).Complement C2: 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).Complement C9: 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.Receptors, Complement: Molecules on the surface of some B-lymphocytes and macrophages, that recognize and combine with the C3b, C3d, C1q, and C4b components of complement.Complement C1s: 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).Complement Membrane Attack Complex: 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.Complement C1r: 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.Complement Inactivator Proteins: 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.Complement C7: 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.Complement C3-C5 Convertases: 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.Complement Factor B: 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.Complement Pathway, Alternative: Complement activation initiated by the interaction of microbial ANTIGENS with COMPLEMENT C3B. When COMPLEMENT FACTOR B binds to the membrane-bound C3b, COMPLEMENT FACTOR D cleaves it to form alternative C3 CONVERTASE (C3BBB) which, stabilized by COMPLEMENT FACTOR P, is able to cleave multiple COMPLEMENT C3 to form alternative C5 CONVERTASE (C3BBB3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.Complement Pathway, Classical: 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.Complement C8: 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.Complement C1: 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.Receptors, Complement 3b: 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.Complement Factor H: 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).Complement C5b: 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.Complement C2a: 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).Receptor, Anaphylatoxin C5a: A G-protein-coupled receptor that signals an increase in intracellular calcium in response to the potent ANAPHYLATOXIN peptide COMPLEMENT C5A.Complement Activating Enzymes: 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.Complement Inactivating Agents: Compounds that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host.Complement Hemolytic Activity Assay: 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.Complement C1 Inactivator Proteins: Serum proteins that inhibit, antagonize, or inactivate COMPLEMENT C1 or its subunits.Receptors, Complement 3d: 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.Anaphylatoxins: 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.Complement Fixation Tests: 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.Complement Factor D: 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.Complement Factor I: 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.Complement C4b-Binding Protein: 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).Complement C3b Inactivator Proteins: 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.Antigens, CD55: 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.Complement C3-C5 Convertases, Classical Pathway: Important enzymes in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. They cleave COMPLEMENT C3 and COMPLEMENT C5.Complement C2b: The N-terminal fragment of COMPLEMENT 2, released by the action of activated COMPLEMENT C1S.Antigens, CD59: 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)Cobra Venoms: 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.Antigen-Antibody Complex: 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.Steroid 21-Hydroxylase: 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).Complement C3-C5 Convertases, Alternative Pathway: Important enzymes in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. They cleave COMPLEMENT C3 and COMPLEMENT C5.Complement C1 Inhibitor Protein: 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.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Hemolysis: The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.Complement C3 Convertase, Alternative Pathway: 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.Complement C5 Convertase, Classical Pathway: 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.Molecular Sequence Data: 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.Complement C3 Convertase, Classical Pathway: 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).Antigens, CD46: 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.Opsonin Proteins: 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.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Lupus Erythematosus, Systemic: 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.Complement C5 Convertase, Alternative Pathway: 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.Phagocytosis: The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).Amino Acid Sequence: 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.Complement Pathway, Mannose-Binding Lectin: 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.Properdin: 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.Complement C5a, des-Arginine: 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).Mice, Inbred C57BLMacrophage-1 Antigen: 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.Protein Binding: 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.Neutrophils: 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Kidney Glomerulus: A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.Serum: The clear portion of BLOOD that is left after BLOOD COAGULATION to remove BLOOD CELLS and clotting proteins.Glomerulonephritis, Membranoproliferative: 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.Immunoglobulin M: 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.Schistosoma: 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.Genetic Complementation Test: 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.Enzyme-Linked Immunosorbent Assay: 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.Mice, Knockout: 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.Glomerulonephritis: 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.Arteriolosclerosis: Thickening of the walls of small ARTERIES or ARTERIOLES due to cell proliferation or HYALINE deposition.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Major Histocompatibility Complex: 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.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Autoantibodies: Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.Cells, Cultured: 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.RNA, Messenger: 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.Macrophages: 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.)Cell Line: Established cell cultures that have the potential to propagate indefinitely.Immunity, Innate: 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.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Mutation: 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.Rabbits: 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.Disease Models, Animal: 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.Cloning, Molecular: 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.Mice, Inbred BALB CBinding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Blood Bactericidal Activity: 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.Antigens, CD: 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.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Mannose-Binding Lectin: 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.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Antibodies: 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).Recombinant Proteins: Proteins prepared by recombinant DNA technology.Complement C3 Nephritic Factor: 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.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Immunoglobulins: 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.Haptoglobins: 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.DNA: 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).Surface Plasmon Resonance: 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.Peptides, Cyclic: 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).Lupus Nephritis: 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).Antibodies, Antinuclear: Autoantibodies directed against various nuclear antigens including DNA, RNA, histones, acidic nuclear proteins, or complexes of these molecular elements. Antinuclear antibodies are found in systemic autoimmune diseases including systemic lupus erythematosus, Sjogren's syndrome, scleroderma, polymyositis, and mixed connective tissue disease.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Blotting, Western: 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.Cosmids: Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.Polymerase Chain Reaction: 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.Bacterial Proteins: Proteins found in any species of bacterium.Gene Expression Regulation: 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.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Inflammation: A pathological process characterized by injury or destruction of tissues caused by a variety of cytologic and chemical reactions. It is usually manifested by typical signs of pain, heat, redness, swelling, and loss of function.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Mannose-Binding Protein-Associated Serine Proteases: 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.Adrenal Hyperplasia, Congenital: A group of inherited disorders of the ADRENAL GLANDS, caused by enzyme defects in the synthesis of cortisol (HYDROCORTISONE) and/or ALDOSTERONE leading to accumulation of precursors for ANDROGENS. Depending on the hormone imbalance, congenital adrenal hyperplasia can be classified as salt-wasting, hypertensive, virilizing, or feminizing. Defects in STEROID 21-HYDROXYLASE; STEROID 11-BETA-HYDROXYLASE; STEROID 17-ALPHA-HYDROXYLASE; 3-beta-hydroxysteroid dehydrogenase (3-HYDROXYSTEROID DEHYDROGENASES); TESTOSTERONE 5-ALPHA-REDUCTASE; or steroidogenic acute regulatory protein; among others, underlie these disorders.Species Specificity: 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.Homozygote: An individual in which both alleles at a given locus are identical.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Immunologic Factors: Biologically active substances whose activities affect or play a role in the functioning of the immune system.ZymosanTime Factors: Elements of limited time intervals, contributing to particular results or situations.Protein Structure, Tertiary: 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.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Gene Dosage: The number of copies of a given gene present in the cell of an organism. An increase in gene dosage (by GENE DUPLICATION for example) can result in higher levels of gene product formation. GENE DOSAGE COMPENSATION mechanisms result in adjustments to the level GENE EXPRESSION when there are changes or differences in gene dosage.Haplotypes: The genetic constitution of individuals with respect to one member of a pair of allelic genes, or sets of genes that are closely linked and tend to be inherited together such as those of the MAJOR HISTOCOMPATIBILITY COMPLEX.Membrane Proteins: 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.HLA Antigens: Antigens determined by leukocyte loci found on chromosome 6, the major histocompatibility loci in humans. They are polypeptides or glycoproteins found on most nucleated cells and platelets, determine tissue types for transplantation, and are associated with certain diseases.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Sequence Homology, Nucleic Acid: 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.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Monocytes: Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.Molecular Weight: The sum of the weight of all the atoms in a molecule.Kinetics: The rate dynamics in chemical or physical systems.Fibrinogen: 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.Exons: The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.B-Lymphocytes: Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.Proteinuria: The presence of proteins in the urine, an indicator of KIDNEY DISEASES.Flow Cytometry: 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.Antibody Formation: The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.Serine Endopeptidases: Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.Streptococcus pneumoniae: 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.Collectins: 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.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Genes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.DNA Primers: 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.C-Reactive Protein: A plasma protein that circulates in increased amounts during inflammation and after tissue damage.Genotype: The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.Up-Regulation: A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Lipopolysaccharides: 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)Protein PrecursorsSteroid Hydroxylases: Cytochrome P-450 monooxygenases (MIXED FUNCTION OXYGENASES) that are important in steroid biosynthesis and metabolism.Blotting, Northern: 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.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.DNA, Complementary: 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.Blotting, Southern: A method (first developed by E.M. Southern) for detection of DNA 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.Cytokines: Non-antibody proteins secreted by inflammatory leukocytes and some non-leukocytic cells, that act as intercellular mediators. They differ from classical hormones in that they are produced by a number of tissue or cell types rather than by specialized glands. They generally act locally in a paracrine or autocrine rather than endocrine manner.Macular Degeneration: Degenerative changes in the RETINA usually of older adults which results in a loss of vision in the center of the visual field (the MACULA LUTEA) because of damage to the retina. It occurs in dry and wet forms.Disease Susceptibility: A constitution or condition of the body which makes the tissues react in special ways to certain extrinsic stimuli and thus tends to make the individual more than usually susceptible to certain diseases.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization: A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Pedigree: The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.Polymorphism, Restriction Fragment Length: Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.Gene Frequency: The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.Guinea Pigs: 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.Immune Adherence Reaction: A method for the detection of very small quantities of antibody in which the antigen-antibody-complement complex adheres to indicator cells, usually primate erythrocytes or nonprimate blood platelets. The reaction is dependent on the number of bound C3 molecules on the C3b receptor sites of the indicator cell.Mice, Inbred DBAEscherichia coli: 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.Immunoelectrophoresis: 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.Staphylococcus aureus: Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.Transfection: 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.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Arthritis, Rheumatoid: A chronic systemic disease, primarily of the joints, marked by inflammatory changes in the synovial membranes and articular structures, widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, and by atrophy and rarefaction of bony structures. Etiology is unknown, but autoimmune mechanisms have been implicated.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Proteomics: The systematic study of the complete complement of proteins (PROTEOME) of organisms.Fluorescent Antibody Technique: Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.Interleukin-6: A cytokine that stimulates the growth and differentiation of B-LYMPHOCYTES and is also a growth factor for HYBRIDOMAS and plasmacytomas. It is produced by many different cells including T-LYMPHOCYTES; MONOCYTES; and FIBROBLASTS.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Epithelial Cells: Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Gene Library: A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.Signal Transduction: 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.Genetic Predisposition to Disease: A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.Hemoglobinuria, Paroxysmal: 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.Polymorphism, Single Nucleotide: A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.

Mechanism of complement-dependent haemolysis via the lectin pathway: role of the complement regulatory proteins. (1/26)

Mannan-binding lectin (MBL) is an acute phase protein which activates the classical complement pathway at the level of C4 and C2 via two novel serine proteases homologous to C1r and C1s. We recently reported that haemolysis via this lectin pathway requires alternative pathway amplification. The present experiments sought to establish the basis for this requirement, and hence focused on the activity and regulation of the C3 convertases. Complement activation was normalized between the lectin and classical pathways such that identical amounts of bound C4 and of haemolytically active C4,2 sites were present on the indicator cells. Under these conditions, there was markedly less haemolysis, associated with markedly less C3 and C5 deposited, via the lectin pathway than via the classical pathway, particularly when alternative pathway recruitment was blocked by depletion of factor D. Lectin pathway activation was associated with enhanced binding in the presence of MBL of complement control proteins C4bp and factor H to C4b and C3b, respectively, with decreased stability of the C3-converting enzyme C4b,2a attributable to C4bp. Immunodepletion of C4bp and/or factor H increased lectin pathway haemolysis and allowed lysis to occur in absence of the alternative pathway. Thus, the lectin pathway of humans is particularly susceptible to the regulatory effects of C4bp and factor H, due at least in part to MBL enhancement of C4bp binding to C4b and factor H binding to C3b.  (+info)

Glomerular complement regulation is overwhelmed in passive Heymann nephritis. (2/26)

BACKGROUND: An injection of anti-Fx1A antibodies in rats leads to passive Heymann nephritis (PHN), a model of membranous nephropathy. Fx1A is a crude extract of renal cortex that contains megalin as a principal component. However, when rats are given anti-megalin antibodies, abnormal proteinuria does not occur. Because of the established complement dependence of PHN, we hypothesized that antibodies neutralizing complement regulatory proteins in the rat glomerulus also were required to induce PHN. Two likely targets are Crry and CD59, proteins abundant on the rat podocyte and contained within Fx1A that inhibit the C3 convertase and C5b-9 assembly, respectively. METHODS: Rats were injected with anti-megalin monoclonal antibodies, followed by anti-Crry and/or anti-CD59 F(ab')(2) antibodies five days later. In a second group of experiments, rats were injected with anti-Fx1A or anti-Fx1A immunodepleted of reactivity against Crry and/or CD59. RESULTS: In the setting of podocyte-associated anti-megalin monoclonal antibodies, simultaneous neutralization of Crry and CD59 function led to the development of significant proteinuria (11.0 +/- 2.1 mg/day, P < 0.001 vs. all other groups). In contrast, animals that had neither or only one of these complement regulators inhibited had normal urinary protein excretion (< or =6 mg/day). In animals given anti-Fx1A depleted of anti-Crry and/or anti-CD59, all groups developed typical PHN, characterized by heavy proteinuria and extensive glomerular deposition of C3 and C5b-9. CONCLUSION: Crry and CD59 play an important role in restraining complement-mediated injury following subepithelial immune complex deposition; however, in PHN, their regulatory capacity is overwhelmed.  (+info)

Role of membrane cofactor protein (CD46) in regulation of C4b and C3b deposited on cells. (3/26)

C4b and C3b deposited on host cells undergo limited proteolytic cleavage by regulatory proteins. Membrane cofactor protein (MCP; CD46), factor H, and C4b binding protein mediate this reaction, known as cofactor activity, that also requires the plasma serine protease factor I. To explore the roles of the fluid phase regulators vs those expressed on host cells, a model system was used examining complement fragments deposited on cells transfected with human MCP as assessed by FACS and Western blotting. Following incubation with Ab and complement on MCP(+) cells, C4b was progressively cleaved over the first hour to C4d and C4c. There was no detectable cleavage of C4b on MCP(-) cells, indicating that MCP (and not C4BP in the serum) primarily mediates this cofactor activity. C3b deposition was not blocked on MCP(+) cells because classical pathway activation occurred before substantial C4b cleavage. Cleavage, though, of deposited C3b was rapid (<5 min) and iC3b was the dominant fragment on MCP(-) and MCP(+) cells. Studies using a function-blocking mAb further established factor H as the responsible cofactor. If the level of Ab sensitization was reduced 8-fold or if Mg(2+)-EGTA was used to block the classical pathway, MCP efficiently inhibited C3b deposition mediated by the alternative pathway. Thus, for the classical pathway, MCP is the cofactor for C4b cleavage and factor H for C3b cleavage. However, if the alternative pathway mediates C3b deposition, then MCP's cofactor activity is sufficient to restrict complement activation.  (+info)

Regulation of glycoprotein IIb-IIIa receptor function studied with platelets permeabilized by the pore-forming complement proteins C5b-9. (4/26)

Recent evidence suggests that the cytoplasmic domains of platelet glycoprotein (GP) IIb-IIIa are involved in the agonist-initiated transformation of this integrin into a receptor for fibrinogen. To identify intracellular reactions that regulate the receptor function of GP IIb-IIIa, membrane-impermeable agonists and antagonists were introduced into the platelet by permeabilizing the plasma membrane with the pore-forming complement proteins C5b-9. Platelet responses were then analyzed by flow cytometry. Non-lytic concentrations of C5b-9 caused permeabilization of the platelet plasma membrane, as determined by uptake of a water-soluble fluorescent tracer dye. The complement pores were large enough to permit the entry of fluorescein isothiocyanate (FITC)-labeled oligopeptides in a size-dependent manner. Under conditions of low external Ca2+, C5b-9 treatment per se did not activate GP IIb-IIIa, as measured by binding of the activation-dependent antibody FITC-PAC1. However, FITC-PAC1 binding to C5b-9-permeabilized platelets was stimulated by a thrombin receptor agonist acting at the cell surface and by guanosine 5'-O-(thiotriphosphate), a membrane-impermeable activator of G proteins. Permeabilization also permitted the entry of cyclic AMP and the peptide, RFARKGALRQKNV, a pseudo-substrate inhibitor of protein kinase C. Each of these inhibited agonist-induced FITC-PAC1 binding to permeabilized platelets but not to intact platelets. Agonist-induced GP IIb-IIIa activation in permeabilized platelets was also inhibited by tyrphostin-23, a protein tyrosine kinase inhibitor. Thus, C5b-9 can be used to permeabilize the plasma membrane to permit the selective entry of small peptides and other bioactive compounds into permeabilized platelets. Results obtained with these platelets indicate that GP IIb-IIIa receptor function is regulated by a network of signaling reactions involving G proteins, serine/threonine kinases, and tyrosine kinases.  (+info)

Persistent complement activation on tumor cells in breast cancer. (5/26)

The neoantigens of the C5b-9 complement complex, IgG, C3, C4, S-protein/vitronectin, fibronectin, and macrophages were localized on 17 samples of breast cancer and on 6 samples of benign breast tumors using polyclonal or monoclonal antibodies and the streptavidin-biotin-peroxidase technique. All the tissue samples with carcinoma in each the TNM stages presented C5b-9 deposits on the membranes of tumor cells, thin granules on cell remnants, and diffuse deposits in the necrotic areas. When chemotherapy and radiation therapy preceded surgery, C5b-9 deposits were more intense and extended. The C5b-9 deposits were absent in all the samples with benign lesions. S-protein/vitronectin was present as fibrillar deposits in the connective tissue matrix and as diffuse deposits around the tumor cells, less intense and extended than fibronectin. IgG, C3, and C4 deposits were present only in carcinoma samples. The presence of C5b-9 deposits is indicative of complement activation and its subsequent pathogenetic effects in breast cancer.  (+info)

The quantitative role of alternative pathway amplification in classical pathway induced terminal complement activation. (6/26)

Complement activation with formation of biologically potent mediators like C5a and the terminal C5b-9 complex (TCC) contributes essentially to development of inflammation and tissue damage in a number of autoimmune and inflammatory conditions. A particular role for complement in the ischaemia/reperfusion injury of the heart, skeletal muscle, central nervous system, intestine and kidney has been suggested from animal studies. Previous experiments in C3 and C4 knockout mice suggested an important role of the classical or lectin pathway in initiation of complement activation during intestinal ischaemia/reperfusion injury while later use of factor D knockout mice showed the alternative pathway to be critically involved. We hypothesized that alternative pathway amplification might play a more critical role in classical pathway-induced C5 activation than previously recognized and used pathway-selective inhibitory mAbs to further elucidate the role of the alternative pathway. Here we demonstrate that selective blockade of the alternative pathway by neutralizing factor D in human serum diluted 1 : 2 with mAb 166-32 inhibited more than 80% of C5a and TCC formation induced by solid phase IgM and solid- and fluid-phase human aggregated IgG via the classical pathway. The findings emphasize the influence of alternative pathway amplification on the effect of initial classical pathway activation and the therapeutic potential of inhibiting the alternative pathway in clinical conditions with excessive and uncontrolled complement activation.  (+info)

Recombinant C345C and factor I modules of complement components C5 and C7 inhibit C7 incorporation into the complement membrane attack complex. (7/26)

Complement component C5 binds to components C6 and C7 in reversible reactions that are distinct from the essentially nonreversible associations that form during assembly of the complement membrane attack complex (MAC). We previously reported that the approximately 150-aa residue C345C domain (also known as NTR) of C5 mediates these reversible reactions, and that the corresponding recombinant module (rC5-C345C) binds directly to the tandem pair of approximately 75-residue factor I modules from C7 (C7-FIMs). We suggested from these and other observations that binding of the C345C module of C5 to the FIMs of C7, but not C6, is also essential for MAC assembly itself. The present report describes a novel method for assembling a complex that appears to closely resemble the MAC on the sensor chip of a surface plasmon resonance instrument using the complement-reactive lysis mechanism. This method provides the ability to monitor individually the incorporation of C7, C8, and C9 into the complex. Using this method, we found that C7 binds to surface-bound C5b,6 with a K(d) of approximately 3 pM, and that micromolar concentrations of either rC5-C345C or rC7-FIMs inhibit this early step in MAC formation. We also found that similar concentrations of either module inhibited complement-mediated erythrocyte lysis by both the reactive lysis and classical pathway mechanisms. These results demonstrate that the interaction between the C345C domain of C5 and the FIMs of C7, which mediates reversible binding of C5 to C7 in solution, also plays an essential role in MAC formation and complement lytic activity.  (+info)

Regulatory control of the terminal complement proteins at the surface of human endothelial cells: neutralization of a C5b-9 inhibitor by antibody to CD59. (8/26)

Functionally inhibitory antibody to the plasma membrane complement inhibitor CD59 has been used to investigate control of the terminal complement proteins at the endothelial cell surface. Antibodies against purified human erythrocyte CD59 (polyclonal anti-CD59 and monoclonal antibodies [MoAbs] 1F1 and 1F5) were found to bind specifically to monolayers of cultured human umbilical vein endothelial cells, and by Western blotting to recognize an 18- to 21-Kd endothelial protein. When bound to the endothelial monolayer, anti-CD59 (immunoglobulin G or Fab fragment) potentiated membrane pore formation induced upon C9 binding to C5b-8, and augmented the C5b-9-induced cellular responses, including stimulated secretion of von Willebrand factor and expression of catalytic surface for the prothrombinase enzyme complex. Although potentiating endothelial responses to the terminal complement proteins, anti-CD59 had no effect on the response of these cells to stimulation by histamine. Taken together, these data suggest that human endothelial cells express the CD59 cell surface inhibitor of the terminal complement proteins, which serves to protect these cells from pore-forming and cell-stimulatory effects of the C5b-9 complex. These data also suggest that the inactivation or deletion of this cell surface regulatory molecule would increase the likelihood for procoagulant changes in endothelium exposed to complement activation in plasma.  (+info)

دانلود مقالات isi انگلیسی درباره اکسید روی با ترجمه فارسی - مقالات الزویر ساینس دایرکت Science Direct
1HDF: Crystal Structure of the Calcium-Loaded Spherulin 3A Dimer Sheds Light on the Evolution of the Eye Lens Betagamma-Crystallin Domain Fold
Regenesance is developing nanoparticle formulations of inhibitors of the complement membrane attack complex (MAC) for the treatment of peripheral neuropathy.
A novel cell surface antigen has been identified on a wide range of lymphoid cells and erythrocytes. A mAb YTH 53.1 (CD59) against this antigen enhanced the lysis of human red cells and lymphocytes by homologous complement. Studies of reactive lysis using different species of C56, and of whole serum used as a source of C7-9, indicated that the inhibitory activity of the CD59 antigen is directed towards the homologous membrane attack complex. CD59 antigen was purified from human urine and erythrocyte stroma by affinity chromatography using the mAb YTH 53.1 immobilized on Sepharose, and, following transient expression of a human T cell cDNA library in COS cells, the corresponding cDNA also identified using the antibody. It was found that the CD59 antigen is a small protein (approximately 20 kD as judged by SDS-PAGE, 11.5 kD predicted from the isolated cDNA) sometimes associated with larger components (45 and 80 kD) in urine. The sequence of CD59 antigen is unlike that of other complement ...
Granulocytic infiltrate occurs in the absence of demyelination, terminal complement complex formation, and overt tissue destruction in NMO white matter. a H&
Understanding tumor resistance to T cell immunotherapies is critical to improve patient outcomes. Our study revealed a role for transcriptional suppression of the tumor-intrinsic HLA class I (HLA-I) antigen processing and presentation machinery (APM) in therapy resistance. Low HLA-I APM mRNA levels in melanoma metastases prior to immune checkpoint blockade (ICB) correlated with non-responsiveness to therapy and poor clinical outcome. Patient-derived melanoma cells with silenced HLA-I APM escaped recognition by autologous CD8+ T cells. However, targeted activation of the innate immunoreceptor RIG-I initiated de novo HLA-I APM transcription thereby overcoming T cell resistance. Antigen presentation was restored in interferon (IFN)-sensitive but also immunoedited IFN-resistant melanoma models through RIG-I-dependent stimulation of an IFN-independent salvage pathway involving IRF1 and IRF3. Likewise, enhanced HLA-I APM expression was detected in RIG-I (DDX58)-high melanoma biopsies, correlating with ...
Herein reported is the case of a 15-year-old female without a relevant medical history, who developed severe headaches, speech problems, dizziness, weakness, inability to walk, depressed consciousness, confusion, amnesia and vomiting, 14 days after receiving her first qHPV vaccine injection. After the second vaccine booster, her symptoms worsened and she expired 15 days later. Autopsy revealed cerebral oedema and cerebellar herniation indicative of a focally disrupted blood-brain barrier.. There was no evidence of an active brain infection. Immunohistochemistry (IHC) examination of the brainstem, hippocampus and the cerebellum showed prominent infiltration of T-lymphocytes and macrophages in all brain areas examined. Notably, marked activation of the complement membrane attack complex (MAC) was detected in the cerebellar Purkinje cells, hippocampal neurons and portions of the brainstem. This pattern of MAC activation in the absence of an active brain infection indicates an abnormal triggering of ...
"Entrez Gene: RGC32 response gene to complement 32". Fosbrink M, Niculescu F, Rus H (2005). "The role of c5b-9 terminal ... Regulator of cell cycle RGCC (RGCC) also known as response gene to complement 32 protein (RGC-32) is a protein that in humans ... It is induced by p53 in response to DNA damage, or by sublytic levels of complement system proteins that result in activation ... 1998). "Molecular cloning and characterization of RGC-32, a novel gene induced by complement activation in oligodendrocytes". J ...
... and C5b, which then forms the terminal complement complex C5b-9 which also has prothrombotic and proinflammatory effects. Both ... By inhibiting the complement cascade at this point, the normal, disease-preventing functions of proximal complement system are ... Eculizumab specifically binds to the terminal complement component 5, or C5, which acts at a late stage in the complement ... C5a and C5b-9 cause the complement-mediated events that are characteristic of PNH and aHUS. The metabolism of eculizumab is ...
Hydrophobic sites are probably exposed upon C5 activation because C5b undergoes aggregation when C5 is converted to C5b in the ... The complement component C5 can be also activated by fluid phase C5 convertase. C5 is activated by CVFBb in the presence of ... complement component C6 and the C5b6 complex is formed. However, when C6 is added after C5 has been converted to C5b, the C5b6 ... In these respects, the mode of action of C5 is completely analogous to that of the other components of complement. The C5 step ...
Deposition of the C5b-9 complement attack complex, subsarcolemmal deposition of calcium and expression of MHC1 complex also ...
A complex of the complement proteins C5b, C6, C7, C8, and multiple units of C9. The combination and activation of this range of ... Able to break down fibrin clots, cleave complement protein C3, and activate Factor XII. ... complement proteins forms themembrane attack complex, which is able to insert into bacterial cell walls and causes cell lysis ...
Staphopain A was shown to inhibit activation of the complement system activation by cleaving components that are part of all ... although inactivating C5b). However, it has yet to prove any significant impact on the outcome of infection. Inhibition of ... Staphopain A can cleave and lower the activity α1-antitrypsin, and inactivate several complement system components. ... "Staphylococcal proteases aid in evasion of the human complement system". Journal of Innate Immunity. 6 (1): 31-46. doi:10.1159/ ...
The immune complex serves as an activator that triggers a response from the C5b - C9 complements, which form a membrane attack ... Immunofluorescence microscopy will reveal typical granular deposition of immunoglobulins and complement along the basement ...
C5-convertase cleaves C5 into C5a and C5b. C5b binds sequentially to C6, C7, C8 and then to multiple molecules of C9 to form ... there are several different kinds of regulatory proteins that disrupt the complement activation process: *Complement Receptor 1 ... Complement Factor H can inhibit the formation of the C3 convertase by competing with factor B for binding to C3b;[1] accelerate ... "Inhibition of the alternative complement pathway by antisense oligonucleotides targeting complement factor B improves lupus ...
... inhibiting incorporation into C5b-8 preventing terminal steps in polymerization of the (MAC) in plasma membranes. Genetic ... thus protecting cells from complement-mediated lysis. It has a signaling role, as a GPI anchored molecule, in T cell activation ...
Freshly activated C5b binds to C6 to form a C5b-6 complex, then to C7 forming the C5b-6-7 complex. The C5b-6-7 complex binds to ... If the pre-MAC complexes of C5b-7, C5b-8 or C5b-9 do not insert into a membrane, they can form inactive complexes with Protein ... MAC is composed of a complex of four complement proteins (C5b, C6, C7, and C8) that bind to the outer surface of the plasma ... The membrane attack complex is initiated when the complement protein C5 convertase cleaves C5 into C5a and C5b. All three ...
... a protein of the complement system C5-convertase, an enzyme which splits C5 into C5b Complement component 5a, an inflammatory ... one of the cervical vertebrae of the vertebral column Cervical spinal nerve 5 Complement component 5, ...
... which cleaves C5 into C5a and C5b. C5b associates with C6, C7, C8, and C9, all of which form a complex that results in a pore ... The C1 complement complex binds to these antibodies resulting in its activation via cross proteolysis. This activated C1 ... C3b is the larger of two elements formed by the cleavage of complement component 3, and is considered an important part of the ... The key to the success of the complement system in clearing antigens is regulating the effects of C3b to pathogens alone and ...
C5b initiates the membrane attack pathway, which results in the membrane attack complex (MAC), consisting of C5b, C6, C7, C8, ... Polymorphisms of complement component 3, complement factor B, and complement factor I, as well as deletion of complement factor ... Three biochemical pathways activate the complement system: the classical complement pathway, the alternative complement pathway ... The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells ...
This enzyme then cleaves C5 to C5a, a potent anaphylatoxin, and C5b. The C5b then recruits and assembles C6, C7, C8 and ... complement factor B, and complement factor I, as well as deletion of complement factor H-related 3 and complement factor H- ... Complement deficiencyEdit. Main article: Complement deficiency. It is thought that the complement system might play a role in ... Three biochemical pathways activate the complement system: the classical complement pathway, the alternative complement pathway ...
... along with one of each of the complement components C5b, C6, C7 and C8. Lint TF, Zeitz HJ, Gewurz H (November 1980). "Inherited ... Complement component 9 (C9) is a protein involved in the complement system, which is part of the innate immune system. C9 is a ... 2001). "The complement system and innate immunity". Immunobiology: The Immune System in Health and Disease. New York: Garland ... Complement 9 at the US National Library of Medicine Medical Subject Headings (MeSH). ...
C5b is important in late events of the complement cascade, an orderly series of reactions which coordinates several basic ... C5a is a protein fragment released from cleavage of complement component C5 by protease C5-convertase into C5a and C5b ... Complement peptide C5a, C4a, and C3a receptors". Pharmacol. Rev. 65 (1): 500-43. doi:10.1124/pr.111.005223. PMID 23383423. ... Complement Peptide C5a, C4a, and C3a Receptors". Pharmacological Reviews. 65 (1): 500-543. doi:10.1124/pr.111.005223. PMID ...
... is involved in the complement system. It is cleaved into C5a and C5b: C5a plays an important role in ... C5b forms the first part of the complement membrane attack complex. Deficiency is thought to cause Leiner's disease. Complement ... The C5b macromolecular cleavage product can form a complex with the C6 complement component, and this complex is the basis for ... Identification of the C5b-binding domain in complement C6". J. Biol. Chem. 264 (30): 18041-51. PMID 2808363. Wetsel RA, Lemons ...
2009). "Response gene to complement 32 is required for C5b-9 induced cell cycle activation in endothelial cells". Exp. Mol. ... Complement component 6 is a protein that in humans is encoded by the C6 gene. Complement component 6 is a protein involved in ... 2009). "Complement production by trophoblast cells at the feto-maternal interface". J. Reprod. Immunol. 82 (2): 119-25. doi: ... Gancz D, Donin N, Fishelson Z (2009). "Involvement of the c-jun N-terminal kinases JNK1 and JNK2 in complement-mediated cell ...
Subsequent interactions between C5b and other terminal components C6, C7, C8, and C9 form the membrane attack complex or the ... 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 ...
... bond in complement component C5 alpha-chain to yield C5a and C5b This enzyme is a bimolecular complex of complement fragment Bb ... Alternative-complement-pathway C3/C5 convertase (EC 3.4.21.47, complement component C3/C5 convertase (alternative), proenzyme ... complement C 3(C 5) convertase (amplification), alternative complement pathway C3(C5) convertase, C5 convertase, CVF,Bb, (CVF)- ... Alternative complement pathway Kerr, M.A. (1981). "Human factor B". Methods Enzymol. 80: 102-112. doi:10.1016/s0076-6879(81) ...
... (EC 3.4.21.42, C1 esterase, activated complement C1s, complement C overbar 1r, C1s) is a protein ... complement activation, lectin pathway. • complement activation. • regulation of complement activation. Sources:Amigo / QuickGO ... complement activation, classical pathway. • immune system process. • innate immune response. • ... Sim RB (1981). "The human complement system serine proteases C1r and C1s and their proenzymes". Methods in Enzymology. 80 Pt C ...
Similarly again, C5b is bound and C5a is released. C5b recruits C6, C7, C8 and multiple C9s. C5, C6, C7, C8 and C9 form the ... Complement receptors, collectins, ficolins, pentraxins such as serum amyloid and C-reactive protein, lipid transferases, ... Once bound to the ligands MBL and Ficolin oligomers recruit MASP1 and MASP2 and initiate the lectin pathway of complement ... "/"self turned nonself" type pathogen pattern are also identified and destroyed (e.g. by complement fixation or other cytotoxic ...
... complement c5a, des-arginine MeSH D12.776.124.486.274.450.625 -- complement c5b MeSH D12.776.124.486.274.550 -- complement c6 ... complement c4a MeSH D12.776.124.486.274.024.270 -- complement c5a MeSH D12.776.124.486.274.024.270.255 -- complement c5a, des- ... complement c1r MeSH D12.776.124.486.274.050.290 -- complement c1s MeSH D12.776.124.486.274.150 -- complement c2 MeSH D12.776. ... complement c2b MeSH D12.776.124.486.274.250 -- complement c3 MeSH D12.776.124.486.274.250.250 -- complement c3a MeSH D12.776. ...
... is a member of the immunoglobulin superfamily, with a structure related to the putative primordial form of the family. As members of the immunoglobulin superfamily play fundamental roles in intercellular recognition involved in various immunologic phenomena, differentiation, and development, basigin is thought also to play a role in intercellular recognition (Miyauchi et al., 1991; Kanekura et al., 1991).[9][10] It has a variety of functions. In addition to its metalloproteinase-inducing ability, basigin also regulates several distinct functions, such as spermatogenesis, expression of the monocarboxylate transporter and the responsiveness of lymphocytes.[6] Basigin is a type I integral membrane receptor that has many ligands, including the cyclophilin (CyP) proteins Cyp-A and CyP-B and certain integrins.[11][12][13] It is expressed by many cell types, including epithelial cells, endothelial cells and leukocytes. The human basigin protein contains 269 amino acids that form two heavily ...
Zipfel, P. F., Hallström, T., & Riesbeck, K. (2013). Human complement control and complement evasion by pathogenic microbes- ... C5b käivitab membraaniründe raja, mille tulemusena moodustub membraaniründe kompleks (MAC - membrane attack complex), ... 1,0 1,1 1,2 1,3 Rus, H., Cudrici, C., & Niculescu, F. (2005). The role of the complement system in innate immunity. Immunologic ... 7,0 7,1 Lambris, J. D., Ricklin, D., & Geisbrecht, B. V. (2008). Complement evasion by human pathogens. Nature Reviews. ...
Rus HG, Niculescu F, Vlaicu R: Co-localization of terminal C5b-9 complement complexes and macrophages in human atherosclerotic ... the complement system is thought to be involved in this vascular inflammation [4] Indeed, complement activation products have ... The complement system can be activated via the classical, alternative or lectin pathway, which is activated when Mannose- ... Siezenga MA, Chandie Shaw PK, van der Geest RN, Mollness TE, Daha MR, Rabelink TJ, Berger SP: Enhanced complement activation is ...
... biotinyl 125I-C5b,6, and 131I-C5b,6) were used in equimolar amounts to assemble C5b-7, more than 50% of the biotinyl 125I-C5b,6 ... The conformation of C7 in C5b-7 and in dimeric C7 appeared similar by the following criteria. On formation of C5b-7 from C5b,6 ... C5b-7 complex formation in the fluid phase or on lipid vesicles likewise involves polymerization. C5b-7 sedimented with 17-40S ... Direct evidence showing that the metastable membrane binding site of the C5b-7 complex resides in the C7 subunit was obtained ...
Membrane attack complex (MAC), properdin (P), factor H (fH) and Complement receptor type 1 (CR1) were quantified in urine ... Complement activation occurs in the urinary space in IgAN and the measurement of levels of MAC and fH in the urine could be a ... is mediated by complement activation via the alternative and lectin pathways. Therefore, we focused on molecules stabilizing ... Excretion of complement proteins and its activation marker C5b-9 in IgA nephropathy in relation to renal function. ...
Assembly of the terminal C5b-C9 complement components into the cytolytic C5b-9 complex is accompanied by exposure of ... Monoclonal antibodies against neoantigens of the terminal C5b-9 complex of human complement. Ferdinand Hugo, Dieter Jenne, ... Monoclonal antibodies against neoantigens of the terminal C5b-9 complex of human complement ... Monoclonal antibodies against neoantigens of the terminal C5b-9 complex of human complement ...
Interaction between complement proteins C5b-7 and erythrocyte membrane sialic acid. P Marshall P Marshall ... P Marshall, A Hasegawa, E A Davidson, V Nussenzweig, M Whitlow; Interaction between complement proteins C5b-7 and erythrocyte ... The membrane attack mechanism of complement. Isolation and subunit composition of the C5b-9 complex. ... Complement lysis is inhibited by either masking glycophorin sialic acid with F(ab) fragments of an mAb, or by removal of the ...
Human terminal complement complex C5b-9 (TCC C5b-9) ELISA Kit (MBS262222) product datasheet at MyBioSource, ELISA Kits ... TCC C5b-9 elisa kit :: Human terminal complement complex C5b-9 (TCC C5b-9) ELISA Kit. ... terminal complement complex C5b-9 (TCC C5b-9), ELISA Kit. Popular Item ... Kit for analyzing the presence of the terminal complement complex C5b-9 (TCC C5b-9) ELISA Kit target analytes in biological ...
... for evidence of activation of the terminal pathway of complement. Fluid phase terminal complement complexes (SC5b-9), ... These findings demonstrate intrathecal activation of terminal complement in patients with CNS SS or CNS SLE, and suggest a role ... for terminal complement activation in the pathophysiology of CNS involvement in both SS and SLE. ... Detection of activated terminal complement (C5b-9) in cerebrospinal fluid from patients with central nervous system involvement ...
The complement C5b-9 complexes induced injury of glomerular mesangial cells in rats with Thy-1 nephritis by increasing nitric ... The complement C5b-9 complexes induced injury of glomerular mesangial cells in rats with Thy-1 nephritis by increasing nitric ... Wang, Y., He, Q., Qin, H., Xu, J., Tong, J., Gao, L., & Xu, J. (2006). The complement C5b-9 complexes induced injury of ...
However, we found that urinary complement levels (C3a, C5a, or C5b-9) did not correlate with plasma complement levels among ... and C5a and C5b-9 [r=0.71; P=0.0001]). However, urine levels of C3a, C5a, and C5b-9 did not correlate with plasma complement ... and C5b, which combines with complement proteins C6-9 to form C5b-9 (membrane attack complex). ... The C5b-9 membrane attack complex of complement activation localizes to villous trophoblast injury in vivo and modulates human ...
Compare Complement C5a desArg ELISA Kits from leading suppliers on Biocompare. View specifications, prices, citations, reviews ... Your search returned 190 Complement C5a desArg ELISA ELISA Kit across 11 suppliers. ...
Terminal Complement Complex C5b-9) ELISA Kit OSCAR DIAGNOSTIC SERVICES PVT. LTD.is an India based Company in Delhi. ... Chicken TCC C5b-9 (Terminal Complement Complex C5b-9) ELISA Kit » Chicken TCC C5b-9 (Terminal Complement Complex C5b-9) ELISA ... Chicken TCC C5b-9 (Terminal Complement Complex C5b-9) ELISA Kit. Chicken TCC C5b-9 (Terminal Complement Complex C5b-9) ELISA ... Chicken TCC C5b-9 (Terminal Complement Complex C5b-9) ELISA Kit. Chicken TCC C5b-9 (Terminal Complement Complex C5b-9) ELISA ...
C5b-9 formation.. We next determined whether the formation of the terminal complement complex (the C5b-9 complex), was greater ... C5b-9 complex forms on activated platelets. We investigated whether complement activation on the platelet surface proceeded to ... Effect of complement proteins C5b-9 on blood platelets. Evidence for reversible depolarization of membrane potential. J. Biol. ... Complement proteins C5b-9 initiate secretion of platelet storage granules without increased binding of fibrinogen or von ...
Freshly activated C5b binds to C6 to form a C5b-6 complex, then to C7 forming the C5b-6-7 complex. The C5b-6-7 complex binds to ... If the pre-MAC complexes of C5b-7, C5b-8 or C5b-9 do not insert into a membrane, they can form inactive complexes with Protein ... MAC is composed of a complex of four complement proteins (C5b, C6, C7, and C8) that bind to the outer surface of the plasma ... The membrane attack complex is initiated when the complement protein C5 convertase cleaves C5 into C5a and C5b. All three ...
C5-convertase cleaves C5 into C5a and C5b. C5b binds sequentially to C6, C7, C8 and then to multiple molecules of C9 to form ... there are several different kinds of regulatory proteins that disrupt the complement activation process: *Complement Receptor 1 ... Complement Factor H can inhibit the formation of the C3 convertase by competing with factor B for binding to C3b;[1] accelerate ... "Inhibition of the alternative complement pathway by antisense oligonucleotides targeting complement factor B improves lupus ...
... biotinyl 125I-C5b,6, and 131I-C5b,6) were used in equimolar amounts to assemble C5b-7, more than 50% of the biotinyl 125I-C5b,6 ... biotinyl 125I-C5b,6, and 131I-C5b,6) were used in equimolar amounts to assemble C5b-7, more than 50% of the biotinyl 125I-C5b,6 ... biotinyl 125I-C5b,6, and 131I-C5b,6) were used in equimolar amounts to assemble C5b-7, more than 50% of the biotinyl 125I-C5b,6 ... The conformation of C7 in C5b-7 and in dimeric C7 appeared similar by the following criteria. On formation of C5b-7 from C5b,6 ...
... and C5 complement. These defects make the NOD background a common choice for immunodeficient mouse strains. ,a href=https:// ... Hc, hemolytic complement. Gene Synonym(s). He; CPAMD4; ECLZB; C5b; He; C5; C5a; C5D; C5; Hfib2; hepatic fibrogenesis 2; Hfib2. ... They also lack hemolytic complement, C5. NOD/ShiLtJ mice also are severely hearing-impaired. A variety of mutations causing ... Studies on the polymorphism of the fifth component of complement in laboratory mice. Exp Clin Immunogenet 12(4):253-60PubMed: ...
Hc, hemolytic complement. Gene Synonym(s). He; CPAMD4; ECLZB; C5b; He; C5; C5a; C5D; C5; Hfib2; hepatic fibrogenesis 2; Hfib2. ... Impaired insulin signaling in the B10.D2-Hc(0) H2(d) H2-T18(c)/oSnJ mouse model of complement factor 5 deficiency. Am J Physiol ... Evidence for genetic control of microwave-induced augmentation of complement receptor-bearing B lymphocytes. J Immunol 129(4): ... Nevertheless, macrophages from mouse strains carrying this allele do not secrete complement 5. ...
Study Complement Cascade flashcards from Paul Joshua Barcelona ... Complement from 1 sp will react w/ immunoglobulin of another sp ... Coating of antigen w/ specific complement peptide by specificreceptor on phagocytes for ingestion ...
Identification of the C5b-binding domain in complement C6.". Haefliger J.-A., Tschopp J., Vial N., Jenne D.E.. J. Biol. Chem. ... "Structural homology of complement protein C6 with other channel-forming proteins of complement.". Chakravarti D.N., Chakravarti ... Component of the membrane attack complex (MAC). MAC assembly is initiated by proteolytic cleavage of C5 into C5a and C5b. C5b ... R-HSA-166665 Terminal pathway of complement. R-HSA-977606 Regulation of Complement cascade. ...
C5b complexes with C6,7 and 8 to form a complex in the membrane that C9 polymerises on to form a channel. - not as imp as C3b ... receptors for complement and Fc are present on phagocytes = opsonins. 1 - receptor binding, acting assembly triggered to engulf ... 1 - complement fixation (binds bacterial surfaces) to target for phagocytosis (opsonisation). 2 - cleaves C5 ... both are phagocytes but they complement each other.. - macrophages are resident as sentinel cells, neutrophils infiltrate in ...
Terminal complement proteins C5b-9 release basic fibroblast growth factor and platelet-derived growth factor from endothelial ... Role of complement and complement receptor C1qR in the antibody-independent killing of group B streptococcus. ... Complement receptor type 1 (CR1, CD35) is a receptor for C1q.. Klickstein LB, Barbashov SF, Liu T, Jack RM, Nicholson-Weller A. ... Paramyosin inhibits complement C1.. Laclette JP, Shoemaker CB, Richter D, Arcos L, Pante N, Cohen C, Bing D, Nicholson-Weller A ...
... complement decay-accelerating factor (DAF), immunoglobulin D (IGHD), complement component C8 (C8), complement C1q subcomponent ... CD4+ cells, macrophages, MHC-I and C5b-9 involve the pathogenesis of dysferlinopathy. International Journal of Clinical and ... On the other hand, the circulating concentrations of two complement inhibitors, complement decay accelerating factor (DAF), and ... Pro-inflammatory biomarkers and complement factors. By focusing on young GC-naïve DMD patients, we were able to identify a ...
Complement Systems: Methods and Protocols is composed of 32 individual chapters that describe a variety of protocols to purify ... and analyze the activity of the individual complement components or path ... Quantification of Complement C5b-9 Binding to Cells by Flow Cytometry Oren Moskovich, Zvi Fishelson ... activation in humans activation in model animals complement system complement system activation disease health homeostasis ...
This enzyme then cleaves C5 to C5a, a potent anaphylatoxin, and C5b. The C5b then recruits and assembles C6, C7, C8 and ... complement factor B, and complement factor I, as well as deletion of complement factor H-related 3 and complement factor H- ... Complement deficiencyEdit. Main article: Complement deficiency. It is thought that the complement system might play a role in ... Three biochemical pathways activate the complement system: the classical complement pathway, the alternative complement pathway ...
Finally, production of the membrane attack complex (C5b-9) may play a protective role in the setting of sepsis, since C5b-9 has ... 1) The complement system has long been perceived as being dangerous to "play" with. Such reluctance to tamper with complement ... 2. Complement Pathway Activation. Figure 1 is a simplified version of the various pathways of complement activation. ... F. Fredslund, N. S. Laursen, P. Roversi et al., "Structure of and influence of a tick complement inhibitor on human complement ...
  • Enhanced peripheral complement activation has long been considered as one of the major pathogenic elements of immune thrombocytopenia. (haematologica.org)
  • In this study, bone marrow samples from patients with immune thrombocytopenia were divided into two groups based on whether or not complement components were deposited on the surfaces of their mesenchymal stem cells. (haematologica.org)
  • Studies over the years demonstrated that complement takes part in nearly every step of the immune reaction and that it deserves a central position in the immunological research. (frontiersin.org)
  • Small volumes of TCC C5b-9 elisa kit vial(s) may occasionally become entrapped in the seal of the product vial during shipment and storage. (mybiosource.com)
  • The ELISA Kit is designed to detect native, not recombinant, TCC C5b-9. (mybiosource.com)
  • Urine and blood samples were collected on the day of enrollment, with complement activation (C3a, C5a, and C5b-9) measured by ELISA. (ahajournals.org)
  • Your search returned 190 Complement C5a desArg ELISA ELISA Kit across 11 suppliers. (biocompare.com)
  • Consequently, biomarkers of complement dysregulation may be useful for prediction or treatment of disease. (ahajournals.org)
  • Because renal damage with proteinuria is a characteristic pathological feature of preeclampsia, we hypothesized that complement markers in urine, rather than plasma, could better reflect complement dysregulation in disease. (ahajournals.org)
  • however, they did not distinguish preeclampsia from chronic hypertension, supporting our hypothesis that complement markers in urine, rather than plasma, better reflect complement dysregulation. (ahajournals.org)
  • CAMBRIDGE, Mass.--( BUSINESS WIRE )--Ra Pharmaceuticals (NASDAQ:RARX), a clinical stage biopharmaceutical company focusing on the development of next-generation therapeutics for diseases of complement dysregulation, today announced that the European Commission has designated RA101495 as an orphan medicinal product for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). (businesswire.com)
  • Dysregulation of complement activity has, therefore, been connected to various diseases, including autoimmune conditions, thrombotic pathologies and infections. (els.net)
  • Complement dysregulation and deficiencies are connected to disease. (els.net)
  • In this chapter, we focus on the clinical consequence of dysregulation of the alternative pathway (AP) of complement. (asmscience.org)
  • 6 The burden of fetoplacental debris becomes exaggerated in severe preeclampsia, 7 - 10 propagating a systemic inflammatory response and placing strain on both classical and alternative complement signaling pathways ( Figure 1 ) as early as the first trimester. (ahajournals.org)
  • Studies suggest that the mechanisms of thrombosis in PNH and familial HUS are related to platelet activation induced by complement activation. (rupress.org)
  • Investigations into the role of complement in ischemia/reperfusion (I/R) injury have identified common effector mechanisms that depend on the production of C5a and C5b-9 through the cleavage of C3. (frontiersin.org)
  • Less clear however is the mechanism of complement activation that leads to the cleavage of C3 in ischemic tissues and to what extent the potential trigger mechanisms are organ dependent - an important question which informs the development of therapies that are more selective in their ability to limit the injury, yet preserve the other functions of complement where possible. (frontiersin.org)
  • Potential mechanisms of complement-mediated pathology in COVID-19. (jci.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)
  • We also explored the mechanisms behind the complement-mediated tumor growth acceleration that we observed and an approach to overcome it. (aacrjournals.org)
  • However, the larger vessel proliferative intimal changes appear to be independent of complement activation and may be on the basis of other upstream mechanisms. (biomedcentral.com)
  • 4 It has been proposed that these insults trigger intrarenal complement activation, but the mechanisms by which these different conditions activate the alternative pathway within the kidney are not known. (asnjournals.org)
  • In this chapter, the structure and function of the complement receptors on the macrophage and related cells are described. (springer.com)
  • Baumann U and Schmidt RE (2001) The role of Fc receptors and complement in autoimmunity. (els.net)
  • Ravetch JV and Clynes RA (1998) Divergent roles for Fc receptors and complement in vivo. (els.net)
  • therefore, genetic ablation of the gene encoding C3 eliminates essentially all complement-dependent effector activities ( 4 ). (asm.org)
  • Cell exposure to a sublytic dose of complement was shown to increase expression of miR-200 (b and c), suggesting that complement C5b-9 exerts a feedback-regulatory effect on these miRNAs. (jimmunol.org)
  • Devine DV, Siegel RS, Rosse WF (1987) Interactions of the platelets in paroxysmal nocturnal hemoglobinuria with complement. (springer.com)
  • Ra Pharma is developing zilucoplan for generalized myasthenia gravis (gMG), paroxysmal nocturnal hemoglobinuria (PNH), and other complement-mediated disorders. (yahoo.com)
  • Age-related macular degeneration and cancer will be described as examples showing that complement contributes to a large variety of conditions, far exceeding the classical examples of diseases associated with complement deficiencies. (frontiersin.org)
  • This article outlines some of the disease states associated with complement deficiencies and their clinical implications. (medscape.com)
  • We determined whether a reciprocal interaction also exists, whereby platelets can activate complement. (rupress.org)
  • The next step in MAC formation involves C5b-C7 interaction with the beta chain of C8 to form C5b-8. (davidson.edu)