Complement c1q. Medical search

A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.

A glycoprotein that is important in the activation of CLASSICAL COMPLEMENT PATHWAY. C4 is cleaved by the activated COMPLEMENT C1S into COMPLEMENT C4A and COMPLEMENT C4B.

The 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.

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.

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.

The minor fragment formed when C5 convertase cleaves C5 into C5a and COMPLEMENT C5B. C5a is a 74-amino-acid glycopeptide with a carboxy-terminal ARGININE that is crucial for its spasmogenic activity. Of all the complement-derived anaphylatoxins, C5a is the most potent in mediating immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE), smooth MUSCLE CONTRACTION; HISTAMINE RELEASE; and migration of LEUKOCYTES to site of INFLAMMATION.

The 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.

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).

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.

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.

Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).

A 105-kDa serum glycoprotein with significant homology to the other late complement components, C7-C9. It is a polypeptide chain cross-linked by 32 disulfide bonds. C6 is the next complement component to bind to the membrane-bound COMPLEMENT C5B in the assembly of MEMBRANE ATTACK COMPLEX. It is encoded by gene C6.

A 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.

A 302-amino-acid fragment in the alpha chain (672-1663) of C3b. It is generated when C3b is inactivated (iC3b) and its alpha chain is cleaved by COMPLEMENT FACTOR I into C3c, and C3dg (955-1303) in the presence COMPLEMENT FACTOR H. Serum proteases further degrade C3dg into C3d (1002-1303) and C3g (955-1001).

A 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).

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.

Molecules on the surface of some B-lymphocytes and macrophages, that recognize and combine with the C3b, C3d, C1q, and C4b components of complement.

A 77-kDa subcomponent of complement C1, encoded by gene C1S, is a SERINE PROTEASE existing as a proenzyme (homodimer) in the intact complement C1 complex. Upon the binding of COMPLEMENT C1Q to antibodies, the activated COMPLEMENT C1R cleaves C1s into two chains, A (heavy) and B (light, the serine protease), linked by disulfide bonds yielding the active C1s. The activated C1s, in turn, cleaves COMPLEMENT C2 and COMPLEMENT C4 to form C4b2a (CLASSICAL C3 CONVERTASE).

A product of COMPLEMENT ACTIVATION cascade, regardless of the pathways, that forms transmembrane channels causing disruption of the target CELL MEMBRANE and cell lysis. It is formed by the sequential assembly of terminal complement components (COMPLEMENT C5B; COMPLEMENT C6; COMPLEMENT C7; COMPLEMENT C8; and COMPLEMENT C9) into the target membrane. The resultant C5b-8-poly-C9 is the "membrane attack complex" or MAC.

A 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.

Serum proteins that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host. The complement system is tightly regulated by inactivators that accelerate the decay of intermediates and certain cell surface receptors.

A 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.

Serine proteases that cleave COMPLEMENT C3 into COMPLEMENT C3A and COMPLEMENT C3B, or cleave COMPLEMENT C5 into COMPLEMENT C5A and COMPLEMENT C5B. These include the different forms of C3/C5 convertases in the classical and the alternative pathways of COMPLEMENT ACTIVATION. Both cleavages take place at the C-terminal of an ARGININE residue.

A 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 activation initiated by the interaction of microbial ANTIGENS with COMPLEMENT C3B. When COMPLEMENT FACTOR B binds to the membrane-bound C3b, COMPLEMENT FACTOR D cleaves it to form alternative C3 CONVERTASE (C3BBB) which, stabilized by COMPLEMENT FACTOR P, is able to cleave multiple COMPLEMENT C3 to form alternative C5 CONVERTASE (C3BBB3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.

Complement activation initiated by the binding of COMPLEMENT C1 to ANTIGEN-ANTIBODY COMPLEXES at the COMPLEMENT C1Q subunit. This leads to the sequential activation of COMPLEMENT C1R and COMPLEMENT C1S subunits. Activated C1s cleaves COMPLEMENT C4 and COMPLEMENT C2 forming the membrane-bound classical C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.

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.

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.

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.

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).

The larger fragment generated from the cleavage of C5 by C5 CONVERTASE that yields COMPLEMENT C5A and C5b (beta chain + alpha' chain, the residual alpha chain, bound by disulfide bond). C5b remains bound to the membrane and initiates the spontaneous assembly of the late complement components to form C5b-8-poly-C9, the MEMBRANE ATTACK COMPLEX.

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

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

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.

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

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.

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

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.

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.

Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.

A serum protein which is important in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. This enzyme cleaves the COMPLEMENT C3B-bound COMPLEMENT FACTOR B to form C3bBb which is ALTERNATIVE PATHWAY C3 CONVERTASE.

A plasma serine proteinase that cleaves the alpha-chains of C3b and C4b in the presence of the cofactors COMPLEMENT FACTOR H and C4-binding protein, respectively. It is a 66-kDa glycoprotein that converts C3b to inactivated C3b (iC3b) followed by the release of two fragments, C3c (150-kDa) and C3dg (41-kDa). It was formerly called KAF, C3bINF, or enzyme 3b inactivator.

A serum protein that regulates the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It binds as a cofactor to COMPLEMENT FACTOR I which then hydrolyzes the COMPLEMENT C4B in the CLASSICAL PATHWAY C3 CONVERTASE (C4bC2a).

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.

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.

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

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

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)

Venoms from snakes of the genus Naja (family Elapidae). They contain many specific proteins that have cytotoxic, hemolytic, neurotoxic, and other properties. Like other elapid venoms, they are rich in enzymes. They include cobramines and cobralysins.

The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.

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).

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

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.

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.

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

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

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.

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

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

A 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.

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.

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

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.

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

A 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.

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

Complement activation triggered by the interaction of microbial POLYSACCHARIDES with serum MANNOSE-BINDING LECTIN resulting in the activation of MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. As in the classical pathway, MASPs cleave COMPLEMENT C4 and COMPLEMENT C2 to form C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.

A 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.

A derivative of complement C5a, generated when the carboxy-terminal ARGININE is removed by CARBOXYPEPTIDASE B present in normal human serum. C5a des-Arg shows complete loss of spasmogenic activity though it retains some chemotactic ability (CHEMOATTRACTANTS).

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

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.

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.

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.

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

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

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.

A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally being called a macroglobulin.

A 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.

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.

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.

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.

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.

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

Antibodies produced by a single clone of cells.

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.

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.

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

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

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 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.

Established cell cultures that have the potential to propagate indefinitely.

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.)

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

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.

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

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.

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.

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.

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

Proteins prepared by recombinant DNA technology.

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

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.

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.

A specific mannose-binding member of the collectin family of lectins. It binds to carbohydrate groups on invading pathogens and plays a key role in the MANNOSE-BINDING LECTIN COMPLEMENT PATHWAY.

A 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).

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

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).

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.

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.

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.

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

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

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

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.

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.

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).

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).

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.

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.

Plasmids containing at least one cos (cohesive-end site) of PHAGE LAMBDA. They are used as cloning vehicles.

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

An individual in which both alleles at a given locus are identical.

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.

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.

Proteins found in any species of bacterium.

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.

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.

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

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.

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.

Histochemical localization of immunoreactive substances using labeled antibodies as reagents.

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.

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.

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

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.

Biologically active substances whose activities affect or play a role in the functioning of the immune system.

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.

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.

Glycoproteins found on the membrane or surface of cells.

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

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

The rate dynamics in chemical or physical systems.

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.

The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.

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

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.

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.

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.

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.

Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.

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

The presence of proteins in the urine, an indicator of KIDNEY DISEASES.

The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.

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

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.

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.

A class of C-type lectins that target the carbohydrate structures found on invading pathogens. Binding of collectins to microorganisms results in their agglutination and enhanced clearance. Collectins form trimers that may assemble into larger oligomers. Each collectin polypeptide chain consists of four regions: a relatively short N-terminal region, a collagen-like region, an alpha-helical coiled-coil region, and carbohydrate-binding region.

A 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.

A latent susceptibility to disease at the genetic level, which may be activated under certain conditions.

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.

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

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.

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.

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.

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.

A single nucleotide variation in a genetic sequence that occurs at appreciable frequency in the population.

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.

The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.

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

Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)

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

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.

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.

Cytochrome P-450 monooxygenases (MIXED FUNCTION OXYGENASES) that are important in steroid biosynthesis and metabolism.

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.

Any method used for determining the location of and relative distances between genes on a chromosome.

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.

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.

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.

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).

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.

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

Immunoglobulins produced in a response to BACTERIAL ANTIGENS.

Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.

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.

A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.

A 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.

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.

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.

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.

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.

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

The systematic study of the complete complement of proteins (PROTEOME) of organisms.

The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.

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.

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.

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.

C1qRP is a heavily O-glycosylated cell surface protein involved in the regulation of phagocytic activity. (1/737)

C1q, mannose-binding lectin (MBL), and pulmonary surfactant protein A (SPA) interact with human monocytes and macrophages, resulting in the enhancement of phagocytosis of suboptimally opsonized targets. mAbs that recognize a cell surface molecule of 126,000 Mr, designated C1qRP, have been shown to inhibit C1q- and MBL-mediated enhancement of phagocytosis. Similar inhibition of the SPA-mediated enhancement of phagocytosis by these mAbs now suggests that C1qRP is a common component of a receptor for these macromolecules. Ligation of human monocytes with immobilized R3, a IgM mAb recognizing C1qRP, also triggers enhanced phagocytic capacity of these cells in the absence of ligand, verifying the direct involvement of this polypeptide in the regulation of phagocytosis. While the cDNA for C1qRP encodes a 631 amino acid membrane protein, Chinese hamster ovary cells transfected with the cDNA of the C1qRP coding region express a surface glycoprotein with the identical 126,000 Mr in SDS-PAGE as the native C1qRP. Use of glycosylation inhibitors, cleavage of the mature C1qRP with specific glycosidases, and in vitro translation of C1qRP cDNA demonstrated that both posttranslational glycosylation and the nature of the amino acid sequence of the protein contribute to the difference between its predicted m.w. and its migration on SDS-PAGE. These results verify that the cDNA cloned codes for the mature C1qRP, that C1qRP contains a relatively high degree of O-linked glycoslyation, and that C1qRP cross-linked directly by monoclonal anti-C1qRP or engaged as a result of cell surface ligation of SPA, as well as C1q and MBL, enhances phagocytosis. (+info)

Alzheimer's beta-amyloid peptides can activate the early components of complement classical pathway in a C1q-independent manner. (2/737)

beta-Amyloid (beta-A) accumulates in the brain of patients with Alzheimer's disease (AD) and is presumably involved in the pathogenesis of this disease, on account of its neurotoxicity and complement-activating ability. Although assembly of beta-A in particular aggregates seems to be crucial, soluble non-fibrillar beta-A may also be involved. Non-fibrillar beta-A does not bind C1q, so we investigated alternative mechanisms of beta-A-dependent complement activation in vitro. On incubation with normal human plasma, non-fibrillar beta-A 1-42, and truncated peptide 1-28, induced dose-dependent activation of C1s and C4, sparing C3, as assessed by densitometric analysis of immunostained membrane after SDS-PAGE and Western blotting. The mechanism of C4 activation was not dependent on C1q, because non-fibrillar beta-A can still activate C1s and C4 in plasma genetically deficient in C1q (C1qd). In Factor XII-deficient plasma (F.XIId) the amount of cleaved C4 was about 5-10% less that in C1qd and in normal EDTA plasma; the reconstitution of F.XIId plasma with physiologic concentrations of F.XII resulted in an increased (8-15%) beta-A-dependent cleavage of C4. Thus our results indicate that the C1q-independent activation of C1 and C4 can be partially mediated by the activation products of contact system. Since the activation of contact system and of C4 leads to generation of several humoral inflammatory peptides, non-fibrillar beta-A might play a role in initiating the early inflammatory reactions leading to a multistep cascade contributing to neuronal and clinical dysfunction of AD brain. (+info)

C1q binding to liposomes is surface charge dependent and is inhibited by peptides consisting of residues 14-26 of the human C1qA chain in a sequence independent manner. (3/737)

Complement activation by anionic liposomes proceeds by antibody-independent, C1q-initiated activation of the classical pathway. Purified C1q bound to anionic liposomes in an acidic lipid concentration-dependent manner. Saturation binding, but not the apparent association constant, was enhanced by increasing the cardiolipin content of the liposomes or decreasing either the pH or ionic strength of the reaction mixture. These observations indicate the involvement of electrostatic factors in the binding. A highly cationic region in the collagen-like domain of C1q comprised of residues 14-26 of the C1qA polypeptide chain was assessed for involvement in liposome binding. This region has previously been shown to mediate C1q binding to other immunoglobulin-independent activators of the classical pathway of complement. Peptides containing residues 14-26 of C1qA, denoted C1qA14-26, inhibited C1q binding to and complement activation by anionic liposomes. The inhibitory capacity of these cationic peptides had no sequence or conformation specificity. Rather, the amount of positive charge on the peptides was the determining factor. When present in excess, peptides with five cationic residues inhibited C1q binding and complement activation; however, C1q peptides with only two cationic residues did not. In addition to the C1qA14-26 region, other parts of C1q that contain cationic residues may also be involved in C1q binding to anionic liposomes. (+info)

Cutting edge: C1q protects against the development of glomerulonephritis independently of C3 activation. (4/737)

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

EMILIN, a component of the elastic fiber and a new member of the C1q/tumor necrosis factor superfamily of proteins. (5/737)

EMILIN (elastin microfibril interface located protein) is an extracellular matrix glycoprotein abundantly expressed in elastin-rich tissues such as blood vessels, skin, heart, and lung. It occurs associated with elastic fibers at the interface between amorphous elastin and microfibrils. Avian EMILIN was extracted from 19-day-old embryonic chick aortas and associated blood vessels and purified by ion-exchange chromatography and gel filtration. Tryptic peptides were generated from EMILIN and sequenced, and degenerate inosine-containing oligonucleotide primers were designed from some peptides. A set of primers allowed the amplification of a 360-base pair reverse transcription polymerase chain reaction product from chick aorta mRNA. A probe based on a human homologue selected by comparison of the chick sequence with EST data base was used to select overlapping clones from both human aorta and kidney cDNA libraries. Here we present the cDNA sequence of the entire coding region of human EMILIN encompassing an open reading frame of 1016 amino acid residues. There was a high degree of homology (76% identity and 88% similarity) between the chick C terminus and the human sequence as well as between the N terminus of the mature chick protein where 10 of 12 residues, as determined by N-terminal sequencing, were identical or similar to the deduced N terminus of human EMILIN. The domain organization of human EMILIN includes a C1q-like globular domain at the C terminus, a collagenous stalk, and a longer segment in which at least four heptad repeats and a leucine zipper can be identified with a high potential for forming coiled-coil alpha helices. At the N terminus there is a cysteine-rich sequence stretch similar to a region of multimerin, a platelet and endothelial cell component, containing a partial epidermal growth factor-like motif. The native state of the recombinantly expressed EMILIN C1q-like domain to be used in cell adhesion was determined by CD spectra analysis, which indicated a high value of beta-sheet conformation. The EMILIN C1q-like domain promoted a high cell adhesion of the leiomyosarcoma cell line SK-UT-1, whereas the fibrosarcoma cell line HT1080 was negative. (+info)

Antibody-independent classical complement pathway activation and homologous C3 deposition in xeroderma pigmentosum cell lines. (6/737)

Of human malignantly transformed cell lines, xeroderma pigmentosum (XP) cell lines were found to be highly susceptible to homologous complement (C): cells were opsonized by C3 fragments on incubation with diluted normal human serum. C3 fragment deposition on XP cells was Ca2+-dependent and occurred on live cells but not UV-irradiated apoptotic cells. (Ca2+ is required for activation of the classical C pathway via C1q and the lactin pathway via mannose binding lectin (MBL), and the surface of apoptotic cells usually activates the alternative C pathway.) In this study we tested which of the pathways participates in XP cell C3 deposition. In seven cell lines that allowed C3 deposition (i), Clq was shown to be essential but MBL played no role in C activation, (ii) Cls but not MASP bound XP cells for activation, (iii) no antibodies recognizing XP cells were required for homologous C3 deposition, and (iv) the alternative pathway barely participated in C3 deposition. Furthermore, the levels of C-regulatory proteins for host cell protection against C, decay-accelerating factor (DAF, CD55) and membrane cofactor protein (MCP, CD46), were found to be relatively low in almost all XP cell lines compared with normal cells. These results indicate that XP cells activate the classical C pathway in an antibody-independent manner through the expression of a molecule which directly attracts C1q in a C-activating form, and that relatively low levels of DAF and MCP on XP cells facilitate effective C3 deposition. The possible relationship between the pathogenesis of XP and our findings is discussed. (+info)

Neuronal protection in stroke by an sLex-glycosylated complement inhibitory protein. (7/737)

Glycoprotein adhesion receptors such as selectins contribute to tissue injury in stroke. Ischemic neurons strongly expressed C1q, which may target them for complement-mediated attack or C1qRp-mediated clearance. A hybrid molecule was used to simultaneously inhibit both complement activation and selectin-mediated adhesion. The extracellular domain of soluble complement receptor-1 (sCR1) was sialyl Lewis x glycosylated (sCR1sLex) to inhibit complement activation and endothelial-platelet-leukocyte interactions. sCR1 and sCR1sLex colocalized to ischemic cerebral microvessels and C1q-expressing neurons, inhibited neutrophil and platelet accumulation, and reduced cerebral infarct volumes. Additional benefit was conferred by sialyl Lewis x glycosylation of the unmodified parent sCR1 molecule. (+info)

Role of complement component C1q in the IgG-independent opsonophagocytosis of group B streptococcus. (8/737)

We investigated the role of complement component C1q in the IgG-independent opsonophagocytosis of type III group B Streptococcus (GBS) by peripheral blood leukocytes. We report that C1q binds to type III GBS both in normal human serum deficient in IgG specific for type III capsular polysaccharide and in a low-ionic strength buffer. The dissociation constant Kd ranged from 2.0 to 5.5 nM, and the number of binding sites Bmax ranged from 630 to 1360 molecules of C1q per bacterium (CFU). An acapsular mutant strain of GBS bound C1q even better than the wild type, indicating that the polysaccharide capsule is not the receptor for C1q. In serum, binding of C1q to GBS was associated with activation of the classical complement pathway. However, normal human serum retained significant opsonic activity after complete depletion of C1q, suggesting that the serum contains a molecule that is able to replace C1q in opsonization and/or complement activation. Mannan-binding lectin, known to share some functions with C1q, appeared not to be involved, since its depletion from serum had little effect on opsonic activity. Excess soluble C1q or its collagen-like fragment inhibited phagocytosis mediated by normal human serum, suggesting that C1q may compete with other opsonins for binding to receptor(s) on phagocytes. We conclude that, although C1q binds directly to GBS, C1q binding is neither necessary nor sufficient for IgG-independent opsonophagocytosis. The results raise the possibility that additional unknown serum factor(s) may contribute to opsonization of GBS directly or via a novel mechanism of complement activation. (+info)

Bohlson SS, O'Conner SD, Hulsebus HJ, Ho MM, Fraser DA (2014-08-21). "Complement, c1q, and c1q-related molecules regulate ...

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

The C-terminal NC1 domain has complement C1q-like structure. Collagen X forms hexamer complexes through the association of NC1 ...

https://en.wikipedia.org/wiki/Collagen,_type_X,_alpha_1

Overall this protein shows similarity to the complement 1Q factors (C1Q). However, when the 3-dimensional structure of the ... Shapiro L, Scherer PE (March 1998). "The crystal structure of a complement-1q family protein suggests an evolutionary link to ... "A novel serum protein similar to C1q, produced exclusively in adipocytes". The Journal of Biological Chemistry. 270 (45): 26746 ...

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

Opsonins include Mfge8, Gas6, Protein S, antibodies and complement factors C1q and C3b. Phagoptosis has multiple functions ... Pathogenic cells such as bacteria can be opsonised by antibodies or complement factors, enabling their phagocytosis and ...

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

C1q associates with C1r and C1s in order to yield the first component of the serum complement system. Deficiency of C1q has ... and C-chains of human complement subcomponent C1q. The complete derived amino acid sequence of human C1q". Biochem. J. 274 (2 ... Complement C1q subcomponent subunit A is a protein that in humans is encoded by the C1QA gene. This gene encodes a major ... 1994). "The envelope glycoprotein of HIV-1 gp120 and human complement protein C1q bind to the same peptides derived from three ...

https://en.wikipedia.org/wiki/C1QA

Early components of the classical complement pathway (C1q or C4) are usually not seen. Electron microscopy confirms electron- ... Some HLA alleles have been suspected along with complement phenotypes as being genetic factors. Non-aggressive Berger's disease ... complement levels, ANA, and LDH. Protein electrophoresis and immunoglobulin levels can show increased IgA in 50% of all ...

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

Deposition of complement protein C3 (and sometimes C1q) may also be seen in LHCDD. Heavy Chain Deposition Disease (HCDD) ... Deposition of complement protein C3 (and sometimes Cq1) may also be seen in HCDD. Early treatment is recommended in MIDD to ...

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

... fibromodulin activates the classical pathway of complement by directly binding C1q". The Journal of Biological Chemistry. 280 ( ...

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

APOE qualifies as a checkpoint inhibitor of the classical complement pathway by complex formation with activated C1q. ... March 2019). "ApoE attenuates unresolvable inflammation by complex formation with activated C1q". Nature Medicine. 25 (3): 496- ...

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

Specifically, complement factors C1q and C3 have been found to have a role in microglia-mediated synaptic pruning. Carriers of ... Genes in the Complement Component 4 (C4) locus of the major histocompatibility complex (MHC), which encode for complement ... The fact that some of these complement factors are involved in signaling during synaptic pruning also seems to suggest that ... The proposed mechanism for this interaction is increased complement factor C3 deposition onto synaptosomes as a consequence of ...

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

Complement C1q tumor necrosis factor-related protein 1 is a protein that in humans is encoded by the C1QTNF1 gene. C1QTNF1 has ... "Entrez Gene: C1QTNF1 C1q and tumor necrosis factor related protein 1". Innamorati G, Whang MI, Molteni R, Le Gouill C, ... Innamorati G, Bianchi E, Whang MI (June 2006). "An intracellular role for the C1q-globular domain". Cellular Signalling. 18 (6 ...

https://en.wikipedia.org/wiki/C1QTNF1

... binds with high affinity to the complement component C1q, the extracellular matrix component TNFα induced protein 6 ( ... In addition, preincubation of apoptotic cells with PTX3 enhances C1q binding and C3 deposition on the cell surface, suggesting ... PTX3 activates the classical pathway of complement activation and facilitates pathogen recognition by macrophages and DCs. ... protects the cells from assembly of the terminal complement components, and sustains an antiinflammatory innate immune response ...

https://en.wikipedia.org/wiki/PTX3

Complement C1q tumor necrosis factor-related protein 3 is a protein that in humans is encoded by the C1QTNF3 gene. GRCh38: ... "Entrez Gene: C1QTNF3 C1q and tumor necrosis factor related protein 3". Human C1QTNF3 genome location and C1QTNF3 gene details ... Wölfing B, Buechler C, Weigert J, Neumeier M, Aslanidis C, Schöelmerich J, Schäffler A (Jul 2008). "Effects of the new C1q/TNF- ...

https://en.wikipedia.org/wiki/C1QTNF3

"Secreted chondroitin sulfate proteoglycan of human B cell lines binds to the complement protein C1q and inhibits complex ... complement binding protein (CBP)-like domains, immunoglobulin folds and proteoglycan tandem repeats. Aggrecan is a critical ...

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

"Secreted chondroitin sulfate proteoglycan of human B cell lines binds to the complement protein C1q and inhibits complex ...

https://en.wikipedia.org/wiki/CSPG4

The human complement subcomponent C1q associates with C1r and C1s in order to yield the first component of the serum complement ... of C1q". J Exp Med. 179 (6): 1809-21. doi:10.1084/jem.179.6.1809. PMC 2191527. PMID 8195709. "Entrez Gene: C1QBP complement ... Complement component 1 Q subcomponent-binding protein, mitochondrial is a protein that in humans is encoded by the C1QBP gene. ... Braun L, Ghebrehiwet B, Cossart P (2000). "gC1q-R/p32, a C1q-binding protein, is a receptor for the InlB invasion protein of ...

https://en.wikipedia.org/wiki/C1QBP

... which binds C1q, and prevents it from initiating complement activation. Due to the importance of C3b, disruptions resulting in ... 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 ...

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

In both cases C1q activates complement, resulting in the cells being marked for phagocytosis by C3b and C4b. C1q is an ... C1q association eventually leads to the recruitment of complement C4b and C3b, both of which are recognized by complement ... Complement proteins involved in innate opsonization include C4b, C3b and iC3b. In the alternative pathway of complement ... Both IgM and IgG undergo conformational change upon binding antigen that allows complement protein C1q to associate with the Fc ...

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

C1q, the first component of the complement system, encounters conformational change that leads to C3 convertase breaking C3 ... or complement mediated. They then looked at the complement factors and immunoglobulin deposits to identify the underlying cause ... Inactive and active complement proteins that split fragments are found in the glomeruli. There are currently drugs available ... C3a, C5a, IL-8 are all chemotactic factors of the activated complement system. Part of their role is to recruit ...

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

It is the first component of the classical complement pathway and is composed of the subcomponents C1q, C1r and C1s. The C1 ... Activation of the C1 complex initiates the classical complement pathway. This occurs when C1q binds to antigen-antibody ... Such binding of C1q leads to conformational changes in the C1q molecule, which activates the associated C1r molecules. Active ... The C1 complex (complement component 1, C1) is a protein complex involved in the complement system. ...

https://en.wikipedia.org/wiki/C1_complex

... appears to influence fibrillogenesis, and also interacts with fibronectin, thrombospondin, the complement component C1q ... Krumdieck R, Höök M, Rosenberg LC, Volanakis JE (December 1992). "The proteoglycan decorin binds C1q and inhibits the activity ...

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

C1q is an integral component within the complement pathway - a complicated cascade of protein interactions, culminating in an ... The anti-C1q antibodies found in patients with hypocomplementemic urticarial vasculitis activate C1q, which instigates ... Consequently, levels of all complement proteins become low. The complement pathway is composed of several subset pathways: the ... classical complement pathway). In brief, the crucial role of C1q in the pathway is its importance as the first protein to start ...

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

... and complement nephropathy, such as C1Q nephropathy. IgA nephropathy is the most common cause of MesPGN. It is thought ... The increase in the number of mesangial cells can be diffuse or local and immunoglobulin and/or complement deposition can also ... and complement and coagulation cascade activation. The inflammatory response includes endothelial and mesangial cell ...

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

... suppress the activation of the classical pathway of complement in vitro by binding to solid-phase or fluid-phase complement C1q ... suppress anti-inflammatory mediators and regulate complement activation argues that defensins upregulate innate host ...

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

... and globular heads of complement C1q receptor (gC1qR) have mediated attachment in cultured cells too. Entry may proceed through ... Integrins are considered to be the main receptors for hantaviruses in vitro, but complement decay-accelerating factor (DAF) ...

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

Complement C1q tumor necrosis factor-related protein 3 C5orf45: Chromosome 5 open reading frame 45 CPLANE1: Ciliogenesis And ... excision repair cross-complementing rodent repair deficiency, complementation group 8 FAF2: encoding protein Fas associated ...

https://en.wikipedia.org/wiki/Chromosome_5

... while the former is also found in complement protein C1q and collectins, which include mannose-binding lectin and lung ... Matsushita M, Endo Y, Fujita T (2000). "Cutting edge: complement-activating complex of ficolin and mannose-binding lectin- ... binds patterns of acetyl groups and activates complement". Scand. J. Immunol. 62 (5): 462-73. doi:10.1111/j.1365-3083.2005. ...

https://en.wikipedia.org/wiki/FCN1

... in order to activate the complement system via C1q. CRP is synthesized by the liver in response to factors released by ... This activates the complement system, promoting phagocytosis by macrophages, which clears necrotic and apoptotic cells and ... Others have shown that CRP can exacerbate ischemic necrosis in a complement-dependent fashion and that CRP inhibition can be a ... It is thought to assist in complement binding to foreign and damaged cells and enhances phagocytosis by macrophages (opsonin- ...

https://en.wikipedia.org/wiki/C-reactive_protein

Besides complement particles C1q and C3b which help to opsonize the apoptotic cells, also thrombospondin, pentraxins (C- ... components of complement pathways (e.g. C1q, C3b) and other molecules found in extracellular space. Collectins (e.g. mannose- ... interacts with calreticulin which is a known C1q receptor), or complement receptors (CR3 and CR4). There is a variety of ... C1q and collectins are other PRRs which could potentially recognize both PAMPs and ACAMPs structures. It is necessary to ...

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

... a human protein identified as a putative C1q receptor. C1q belongs to the complement activation proteins and plays a major role ... Stuart GR, Lynch NJ, Day AJ, Schwaeble WJ, Sim RB (December 1997). "The C1q and collectin binding site within C1q receptor ( ... Peerschke EI, Ghebrehiwet B (November 1990). "Platelet C1q receptor interactions with collagen- and C1q-coated surfaces". ... Norsworthy PJ, Taylor PR, Walport MJ, Botto M (August 1999). "Cloning of the mouse homolog of the 126-kDa human C1q/MBL/SP-A ...

https://en.wikipedia.org/wiki/CD93

... while the complement system is activated by binding the C1q protein complex. IgG or IgM can bind to C1q, but IgA cannot, ... these phagocytes are attracted by certain complement molecules generated in the complement cascade. Second, some complement ... Complement activation (fixation), in which antibodies that are latched onto a foreign cell encourage complement to attack it ... Activation of complementEdit. Antibodies that bind to surface antigens (for example, on bacteria) will attract the first ...

https://en.m.wikipedia.org/wiki/Antibody

C1q - another part of the C1 complex C1r - another part of the C1 complex MASP-2 - a protein similar to C1s, part of the lectin ... Complement component 1s (EC 3.4.21.42, C1 esterase, activated complement C1s, complement C overbar 1r, C1s) is a protein ... "Entrez Gene: C1S Complement component 1, s subcomponent". Luo C, Thielens NM, Gagnon J, Gal P, Sarvari M, Tseng Y, Tosi M, ... Complement+C1s at the US National Library of Medicine Medical Subject Headings (MeSH) Human C1S genome location and C1S gene ...

https://en.wikipedia.org/wiki/Complement_component_1s

... complement c1 MeSH D12.776.124.486.274.050.270 - complement c1q MeSH D12.776.124.486.274.050.280 - complement c1r MeSH D12.776. ... complement c2 MeSH D12.776.124.486.274.150.500 - complement c2a MeSH D12.776.124.486.274.150.750 - complement c2b MeSH D12.776. ... complement c3c MeSH D12.776.124.486.274.250.260.750 - complement c3d MeSH D12.776.124.486.274.350 - complement c4 MeSH D12.776. ... complement c5b MeSH D12.776.124.486.274.550 - complement c6 MeSH D12.776.124.486.274.650 - complement c7 MeSH D12.776.124.486. ...

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

... while the complement system is activated by binding the C1q protein complex. IgG or IgM can bind to C1q, but IgA cannot, ... these phagocytes are attracted by certain complement molecules generated in the complement cascade. Second, some complement ... complement system. This results in the killing of bacteria in two ways. First, the binding of the antibody and complement ... These loops are referred to as the complementarity-determining regions (CDRs), since their shape complements that of an antigen ...

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

C1q and tumor necrosis factor related protein 5, also known as C1QTNF5, is a protein which in humans is encoded by the C1QTNF5 ... Shapiro L, Scherer PE (March 1998). "The crystal structure of a complement-1q family protein suggests an evolutionary link to ... "Entrez Gene: C1QTNF5 C1q and tumor necrosis factor related protein 5". Tu X, Palczewski K (December 2012). "Crystal structure ... Also, it is necessary for the function of the members of the C1q family. Another feature is having an unusual sequence which is ...

https://en.wikipedia.org/wiki/C1QTNF5

As a member of the LDLR family, LRP1 contains cysteine-rich complement-type repeats, EGF (gene) repeats, β-propeller domains, a ... LRP1 has been shown to interact with: A2-Macroglobulin, β-amyloid precursor protein, APBB1, APOE, Aprotinin, C1S/C1q inhibitor ... and eleven cysteine-rich complement-type repeats, respectively. These repeats bind extracellular matrix proteins, growth ... CALR, CD44, Chylomicron, Circumsporozoite protein, Collectin, Complement C3, CTGF, DLG4, Elastase, Factor IXa, Factor VIIa, ...

https://en.wikipedia.org/wiki/LRP1

The complement system can be activated through three pathways: the classical pathway, the alternative pathway, and the lectin ... Ogden CA, deCathelineau A, Hoffmann PR, Bratton D, Ghebrehiwet B, Fadok VA, Henson PM (September 2001). "C1q and mannose ... The subsequent complement cascade catalyzed by C3-convertase results in creating a membrane attack complex, which causes lysis ... In order to activate the complement system when MBL binds to its target (for example, mannose on the surface of a bacterium), ...

https://en.wikipedia.org/wiki/Mannan-binding_lectin

C1q mediates the classical pathway by activating the C1 complex, which cleaves C4 and C2 into smaller fragments (C4a, C4b, C2a ... 12th European Meeting on Complement in Human Disease12th European Meeting on CHD12th European Meeting on Complement in Human ... C3a is one of the proteins formed by the cleavage of complement component 3; the other is C3b. C3a is a 77 residue ... Anaphylatoxins are small complement peptides that induce proinflammatory responses in tissues. C3a is primarily regarded for ...

https://en.wikipedia.org/wiki/C3a_(complement)

All forms of HAE lead to abnormal activation of the complement system, and all forms can cause swelling elsewhere in the body, ... This serine protease inhibitor (serpin) normally inhibits the association of C1r and C1s with C1q to prevent the formation of ... In this analysis, it is usually a reduced complement factor C4, rather than the C1-INH deficiency itself, that is detected. The ... In hereditary angioedema, bradykinin formation is caused by continuous activation of the complement system due to a deficiency ...

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

Serine proteases then cleave a number of soluble complement proteins leading to complement activation, opsonisation, generation ... Together with pentraxins, collectins and C1q molecules, ficolins constitute the soluble pattern-recognition molecules (PRMs) ... When ficolins bind to their PAMP ligands by their C-terminal fibrinogen-like domain, they initiate the proteolytic complement ... Matsushita, Misao (2018). "Chapter 5 - Ficolins". In Barnum, Scott R.; Schein, Theresa N. (eds.). The Complement FactsBook ( ...

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

The complement component 1, q subcomponent-like 1 (or C1QL1) is encoded by a gene located at chromosome 17q21.31. It is a ... 2007). "C1q and its growing family". Immunobiology. 212 (4-5): 253-66. doi:10.1016/j.imbio.2006.11.001. PMID 17544811. Sie CP, ... It is a member of the C1Q domain proteins which have important signalling roles in inflammation and in adaptive immunity. The ... January 1999). "Cloning and characterization of CRF, a novel C1q-related factor, expressed in areas of the brain involved in ...

https://en.wikipedia.org/wiki/C1QL1

Such proteins include C1q, elastins, PrP, Argonaute 2, and conotoxins, among others. As prolyl hydroxylase requires ascorbate ... Müller W, Hanauske-Abel H, Loos M (October 1978). "Biosynthesis of the first component of complement by human and guinea pig ...

https://en.wikipedia.org/wiki/Procollagen-proline_dioxygenase

The classical complement pathway can be initiated by the binding of antigen-antibody complexes to the C1q protein. The globular ... Alternative complement pathway - another complement system pathway Lectin pathway - another complement system pathway Noris, ... Deficiency in the C1q protein of the classical complement pathway can lead to development of systemic lupus erythematosus. ... The classical complement pathway is one of three pathways which activate the complement system, which is part of the immune ...

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

Complement C1q antibody. Cat# MBS536288. Supplier: MyBiosource. Available at Gentaur Genprice in 5 to 7 Working Days. Place ... Complement C1q]Product Name Synonyme: [Monoclonal Complement C1q; Anti-Complement C1q; C1q; Complement C1q; Complement Cq 1 ... Product Name Synonyme: [Polyclonal Complement C1q; Anti-Complement C1q; Complement Cq 1; Complement Cq -1; C1q; Complement C1q] ... Complement C1q]Product Name Synonyme: [Polyclonal Complement C1q; Anti-Complement C1q; Complement Cq 1; C1q; Complement Cq-1 ...

https://biocheminfo.org/mbs536288-complement-c1q-antibody/

complement C1q-like protein 3. Names. C1q and tumor necrosis factor-related protein 13. C1q/TNF-related protein 13. complement ... complement C1q like 3provided by HGNC. Primary source. HGNC:HGNC:19359 See related. Ensembl:ENSG00000165985 MIM:615227; ... Low Complement C1q/TNF-related Protein-13 Levels are Associated with Childhood Obesity But not Binge Eating Disorder Erbaş İM, ... Low Complement C1q/TNF-related Protein-13 Levels are Associated with Childhood Obesity But not Binge Eating Disorder Title: Low ...

https://www.ncbi.nlm.nih.gov/gene/389941

Complement C1Q. On-line free medical diagnosis assistant. Ranked list of possible diseases from either several symptoms or a ... Complement C1Q. The Complement System - YouTube. A summary of the complement system. This video is from: ..... Personally I ... of bacteria) in order to activate the complement system via the C1Q complex. The CRP gene .... youtube.com - Sat, 18 Oct 2014 ... complement system part 3 (Classical pathway) - YouTube. The Classical pathway of activation of the complement system is a ... ...

https://lookfordiagnosis.com/videos.php?term=Complement+C1Q&lang=1

In the lupus brain, C1q was increased and localized at synaptic terminals, causing the apposition of phagocytic microglia and ... Here, we show that complement-coordinated elimination of synapses participated in NPSLE in MRL/lpr mice, a lupus-prone murine ... Minocycline-mediated deactivation of microglia, antibody blockade of C1q, or neuronal restoration of Nr4a1 protected lupus mice ... We further determined that neuronal Nr4a1 signaling was essential for attracting C1q synaptic deposition and subsequent ...

https://www.nature.com/articles/s41392-021-00867-y?error=cookies_not_supported&code=f3315543-a0fe-402e-8108-67dbd0f21d4e

Human Complement C1q tumor necrosis factor-related protein 9A(C1QTNF9) ELISA kit ...

https://www.doronscientific.com/product-page/human-complement-c1q-tumor-necrosis-factor-related-protein-9a-c1qtnf9-elisa-kit

Monkey C1q (Complement 1q) ELISA Kit , G-EC-05078 MSRP: Was: Now: $266.00 - $4,134.00 ...

https://caslab.com/rat-apob-apolipoprotein-b-elisa-kit-g-ec-05817/

Shop enQuireBio™ Recombinant Human Complement C1q subcomponent subunit A Protein at Fishersci.ie ... A DNA sequence encoding the Homo sapiens (Human) Complement C1q subcomponent subunit A, was expressed in the hosts and tags ...

https://www.fishersci.ie/shop/products/recombinant-human-complement-c1q-subcomponent-subunit-a-protein-1/15927369

Complement activation plays an important role in local and remote tissue injury associated with gastrointestinal ischemia- ... Tissue C3 deposition in C1q KO and WT, but not C2/fB KO, mice after GI/R demonstrated that complement was activated in C1q KO ... Our data demonstrate that GI/R injury is complement dependent, but does not involve C1q, suggesting that initial complement ... The role of the classical and lectin complement pathways in GI/R injury was evaluated using C1q-deficient (C1q KO), MBL-A/C- ...

https://journals.aai.org/jimmunol/article/174/10/6373/36576/Gastrointestinal-Ischemia-Reperfusion-Injury-Is

PTX3 binds in the fluid phase to C1q, decreasing C1q deposition and subsequent complement activation on apoptotic cells. C1q ... PTX3 binds in the fluid phase to C1q, decreasing C1q deposition and subsequent complement activation on apoptotic cells. C1q ... PTX3 binds in the fluid phase to C1q, decreasing C1q deposition and subsequent complement activation on apoptotic cells. C1q ... PTX3 binds in the fluid phase to C1q, decreasing C1q deposition and subsequent complement activation on apoptotic cells. C1q ...

https://moh-it.pure.elsevier.com/en/publications/the-tissue-pentraxin-ptx3-limits-c1q-mediated-complement-activati

The C1q component of the complement system. * The macrophage scavenger proteins. * Ectodysplasin A ...

https://emedicine.medscape.com/article/2087938-overview

Human C1q-Ab(Anti-Complement 1q Antibody) ELISA Kit. EH2728 FN Test 96T. 524.1 EUR ...

https://genomeboy.com/dog-brucella-ab-test-kit/

Complement C1q like 3. 0.8579. 10. NRG3. Neuregulin 3. 0.8579. 10. PROTEIN EXPRESSION OVERVIEWi Protein expression data is ...

http://www.proteinatlas.org/ENSG00000019505-SYT13/tissue

complement C1q like 2. involved_in. IEA. Ensembl. GO_REF:0000107. NCBI chr15:24,674,175...24,676,961 Ensembl chr15:24,674,861 ... complement C1q like 3. involved_in. IEA. Ensembl. GO_REF:0000107. NCBI chr10:45,357,247...45,368,901 Ensembl chr10:45,359,461 ...

https://rgd.mcw.edu/rgdweb/ontology/annot.html?acc_id=GO:0062237&species=Pig

C1q-engagement with IgG and IgM sort antibodies is the initiating step of classical complement-mediated immunity. The tumor ... Tumor-shed antigen CA125 blocks complement-mediated killing via suppression of C1q-antibody binding.. November 2, 2022. ... Tumor-shed antigen CA125 blocks complement-mediated killing via suppression of C1q-antibody binding. ...

https://www.ncbcs.org/category/control/

... and S2 with enhanced ability to bind Fcγ receptors or complement (C1q), suggesting that exposure to SARS-CoV-2 within this ... C1q protein (MP Biomedicals, USA) was first biotinylated (Thermo Fisher Scientific, USA), then tetramerized with Streptavidin R ... SAPE; Thermo Fisher Scientific) before dimers or tetrameric C1q-PE were being used in one-step detection. For the detection of ...

https://www.nature.com/articles/s41467-020-19545-8?utm_medium=affiliate&utm_source=commission_junction&utm_campaign=3_nsn6445_deeplink_PID100032693&utm_content=deeplink&error=cookies_not_supported&code=1704a2bc-9e52-4444-bf3a-899ebde661c3

complement C1q B chain. LOC107011905. auxin-induced protein 15A-like. LOC106887412. alcohol dehydrogenase 1. ...

https://www.genscript.com/gene/gene-type/protein-coding?search=g

... from b.22.1.1 Complement c1q globular head, B chain: *Species Human (Homo sapiens) [TaxId:9606] from b.22.1.1 Complement c1q ... Protein Complement c1q globular head, B chain [101615] (1 species). hetrotrimer of A, B and C chains. ... More info for Species Human (Homo sapiens) [TaxId:9606] from b.22.1.1 Complement c1q globular head, B chain. Timeline for ... Species Human (Homo sapiens) [TaxId:9606] from b.22.1.1 Complement c1q globular head, B chain appears in SCOPe 2.07. ...

http://scop.berkeley.edu/sunid=101616

7. Recognition protein C1q of innate immunity agglutinates nanodiamonds without activating complement.. A. Belime, N. M. ... 6. Mode of PEG Coverage on Carbon Nanotubes Affects Binding of Innate Immune Protein C1q.. A. Belime, E. Gravel, S. Brenet, S. ... of the surface charge of polydiacetylene micelles on their interaction with human innate immune protein C1q and the complement ... 2. Human Immune Protein C1q Selectively Disaggregates Carbon Nanotubes.. M. Saint-Cricq, J. Carrete, C. Gaboriaud, E. Gravel, E ...

https://www.cea.fr/drf/joliot/en/Pages/research_entities/medicines_healthcare_technologies/scbm/lmt/Publications-nanosciences.aspx

Temporary depletion of complement component C3 or genetic deficiency of C1q significantly delays onset of scrapie. Nat Med. ... Defects in either the complement pathway or follicular dendritic cells result in resistance to peripheral scrapie infection (7, ... such as impairing migrating intestinal dendritic cells or complement pathways involved in complexing PrPRes to follicular ...

https://wwwnc.cdc.gov/eid/article/10/6/03-1130_article

Few studies focus on the immunomodulatory effects of the complement system on MM. This study aims to explore the role of C1q in ... Plasma C1q was found to be significantly reduced in MM patients, and the amount of C1q deposited around the CD138+ cells in BM ... Plasma C1q was found to be significantly reduced in MM patients, and the amount of C1q deposited around the CD138+ cells in ... gC1qR interacts with insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), which also suppressed the function of C1q ...

https://www.frontiersin.org/articles/10.3389/fimmu.2020.01292/full

25] These deposits rarely contain C1q or C4, both components of the classic complement pathway. A recent study also showed ... Complement components and complement activation in acute poststreptococcal glomerulonephritis. Int Arch Allergy Appl Immunol. ... Complement in overt and asymptomatic nephritis after skin infection. J Clin Invest. 1970 Jun. 49(6):1178-87. [QxMD MEDLINE Link ... Complement profiles in acute post-streptococcal glomerulonephritis. Pediatr Nephrol. 1988 Apr. 2(2):219-23. [QxMD MEDLINE Link] ...

https://www.medscape.com/answers/980685-87688/what-is-the-role-of-nephritis-associated-plasmin-receptor-naplr-in-the-pathogenesis-of-acute-poststreptococcal-glomerulonephritis-apsgn

Complement C3 and C4 expression in C1q sufficient and deficient mouse models of Alzheimers disease. J Neurochem. 2008 Sep;106( ... Most people seemed to have favored the latter, until Beth Stevens and I showed that complement component C1q bound to many ... I think the critical question now is whether direct pharmacological blockers of C1q and the classical complement cascade will ... So Beth and I proposed that C1q and the classical complement cascade would be a universal driver of synapse loss in many ...

https://www.alzforum.org/papers/nfkb-activated-astroglial-release-complement-c3-compromises-neuronal-morphology-and-function

... and complement C1q (OR 5.0, p = 0.0068) were associated with seroconverters. Post-treatment levels of IgG1-4 and C3/C1q were ... Thus, high pretreatment and post-treatment levels of natural antibody IgG1-4, complement C3, and/or C1q were significantly ... Serum IgG1-3 and complement C3 levels were significantly higher in HBeAg-positive patients. In pre-treatment, IgG1 (odd ratios ... B1 cell-derived natural antibodies are non-specific polyreactive antibodies and can activate the complement pathway leading to ...

https://www.cdc.gov/library/sciclips/issues/v14issue13.html

Human Complement C1q tumor necrosis factor-related protein 6 (C1QTNF6) ELISA kit , CSB-EL003651HU , CusabioHuman Complement C1q ... Human Complement C1q tumor necrosis factor-related protein 1 (C1QTNF1/CTRP1) ELISA Kit , CSB-E16713h , CusabioHuman Complement ... Human Complement C1q tumor necrosis factor-related protein 1 (C1QTNF1/CTRP1) ELISA Kit , CSB-E16713h Cusabio Elisa ... Human Complement C1q tumor necrosis factor-related protein 6 (C1QTNF6) ELISA kit , CSB-EL003651HU Cusabio Elisa ...

https://joplink.net/mouse-transforming-growth-factor-beta-induced-protein-ig-h3-tgfbi-elisa-kit-csb-el023450mo/

Y. Cai, Q. Yang, Y. Tang et al., "Increased complement C1q level marks active disease in human tuberculosis," PLoS One, vol. 9 ... determine the expression pattern of C1q in peripheral blood mononuclear cells (PBMCs) to explore the function of C1q in TB, ... finding that C1q is closely related to the active disease and disease severity in TB and serves as a diagnostic biomarker for ...

https://www.hindawi.com/journals/crj/2020/4348371/

Decreased complement levels, increased circulating C1q-binding activity, and decreased C4, C3, and CH50 levels are observed in ... Complement activation by Babesia may lead to the generation of tumor necrosis factor (TNF) and interleukin-1 (IL-1). ...

https://emedicine.medscape.com/article/212605-overview

Since DECs are the only ECs, which under physiological conditions, are able to synthesize the complement component C1q [13], an ... We have previously shown that DECs are the only ECs able to express the complement protein C1q under basal physiologic ... conditions [13]. C1q, besides its well-known function as the recognition subcomponent of the complement classical pathway, is ... Bossi, F.; Peerschke, E.I.; Ghebrehiwet, B.; Tedesco, F. Cross-talk between the complement and the kinin system in vascular ...

https://www.mdpi.com/1422-0067/20/7/1604

An Fc region can bind a complement component C1q. In one embodiment, the Fc domain comprises a LALA-PG mutation (e.g., ... An Fc region can bind Fc cell surface receptors and some proteins of the immune complement system. An Fc region exhibits ... effector function, including any one or any combination of two or more activities including complement-dependent cytotoxicity ( ...

https://patents.justia.com/patent/20220251168

is engaged in the development of ANX005-an experimental monoclonal antibody that targets abnormal C1q activity in complement- ... and is meant to suppress C1q and the complete classical complement system. In November 2020, the company initiated a phase 2 ...

https://www.grandviewresearch.com/industry-analysis/huntingtons-disease-treatment-market

... such as C1q, or have a reduced ability to interact with a complement protein, such as C1q. As a result, the synthetic peptide ... 102000000989 Complement System Proteins Human genes 0.000 description 8 * 108010069112 Complement System Proteins Proteins ... The CS of Clqc, representing the major constituent of the human complement subcomponent C1q, and of EMILINs shows that these ... shows the CS of GP1 proteins from Zika virus and human C1q(c). FIG. 6C. shows the CS of human C1q(c) and the Zika GP1 protein ...

https://patents.google.com/patent/US10322171B2/en

Complement C1, the first component of the complement system and activator of the classical pathway, is a complex of three proteins: C1q, C1r, and C1s ( 7 , 8 ). (frontiersin.org)
Complement is a blood test that measures the activity of certain proteins in the liquid portion of your blood. (medlineplus.gov)
The complement system is a group of nearly 60 proteins that are in blood plasma or on the surface of some cells. (medlineplus.gov)
Rarely, people may inherit deficiency of some complement proteins. (medlineplus.gov)
There are nine major complement proteins. (medlineplus.gov)
For example, people with active lupus erythematosus may have lower-than-normal levels of the complement proteins C3 and C4 . (medlineplus.gov)
The cascade activates the complement proteins. (medlineplus.gov)
The collagen-like and the fibrinogen-like domains are also found separately in other proteins such as complement protein C1q, C-type lectins known as collectins, and tenascins. (antikoerper-online.de)
Of all the lectin proteins, only MBL has been shown to have the ability to activate the complement system. (medscape.com)
2017-02-02 · Hypocomplementemic urticarial vasculitis (HUV) is a rare form of vasculitis characterized by inflammation of the small blood vessels and low levels of complement proteins in the blood. (web.app)

A DNA sequence encoding the Homo sapiens (Human) Complement C1q subcomponent subunit A, was expressed in the hosts and tags indicated. (fishersci.ie)

C1q-engagement with IgG and IgM sort antibodies is the initiating step of classical complement-mediated immunity. (ncbcs.org)
the classical pathway initiated by antibodies bound to the surface of foreign bodies and the alternative and lectin pathways that provide an antibody-independent mechanism for complement activation, induced by the presence of bacteria and other micro-organisms. (abcam.com)
C1q attaches to antibodies bound on the pathogen surface, leading to the activation of C1s. (abcam.com)
Introduction: Anti-C1q antibodies have been implicated in the pathogenesis of systemic lupus erythematosus. (endocrine-abstracts.org)
We have previously shown that anti-C1q antibodies are also linked to autoimmune thyroid disorders (AITD). (endocrine-abstracts.org)
The aim of this study was to assess the occurrence of anti-C1q antibodies in pregnant women with AITD.Methods: Serum anti-C1q antibodies were measured during the 9 11th gestational weeks in 103 pregnant women screened positive for AITD, an. (endocrine-abstracts.org)
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 . (bvsalud.org)

This gene encodes a major constituent of the human complement subcomponent C1q. (abnova.com)
This antibody is raised against C1qA which is the A-chain polypeptide of human complement subcomponent C1q. (ptglab.com)

Low Complement C1q/TNF-related Protein-13 Levels are Associated with Childhood Obesity But not Binge Eating Disorder Erbaş İM, et al . (nih.gov)
The Circulating Levels of Complement-C1q/TNF-Related Protein 13 (CTRP13) in Patients with Type 2 Diabetes and its Association with Insulin Resistance. (nih.gov)
Complement 1q-like-3 protein inhibits insulin secretion from pancreatic β-cells via the cell adhesion G protein-coupled receptor BAI3. (nih.gov)
gC1qR interacts with insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3), which also suppressed the function of C1q and regulated CDC28 protein kinase regulatory subunit 1B (CKS1B) mRNA. (frontiersin.org)
The complement protein C3b, along with its cleavage product C3bi, is a potent agent of opsonization in the complement cascade. (medscape.com)
In order to generate an antibody response, an antigen must bind to the complement receptor (CR2) on B cells and the complement protein C3d. (medscape.com)
The MBL protein can activate the C4 and C2 components of complement by forming a complex with serine proteases known as MASP1 and MASP2. (medscape.com)
A novel serum protein similar to C1q, produced exclusively in adipocytes. (medecinesciences.org)
Proteolytic cleavage product of 30-kDa adipocyte complement-related protein increases fatty acid oxidation in muscle and causes weight loss in mice. (medecinesciences.org)

Minocycline-mediated deactivation of microglia, antibody blockade of C1q, or neuronal restoration of Nr4a1 protected lupus mice from synapse loss and NP manifestations. (nature.com)
Tumor-shed antigen CA125 blocks complement-mediated killing via suppression of C1q-antibody binding. (ncbcs.org)
Annexon, Inc. is engaged in the development of ANX005-an experimental monoclonal antibody that targets abnormal C1q activity in complement-mediated neurodegenerative diseases, such as HD. (grandviewresearch.com)
IMSEAR at SEARO: Anti-C1q antibody as a marker of disease activity in systemic lupus erythematosus. (who.int)
Kumar A, Gupta R, Varghese T, Pande RM, Singal VK, Garg OP. Anti-C1q antibody as a marker of disease activity in systemic lupus erythematosus. (who.int)
The present study was conducted to examine the usefulness of anti-C1q antibody as a marker of disease activity in Indian patients with systemic lupus erythematosus (SLE). (who.int)
We standardized the assay for detection of IgG anti-C1q antibody using ELISA. (who.int)
Anti-C1q was found positive in 5 of 9 patients with moderate SLEDAI scores and negative for anti-ds DNA antibody. (who.int)
It is concluded that anti-C1q antibody can serve as a general marker for lupus activity, supplementing the currently used serum markers. (who.int)

Deficiency of C1q has been associated with lupus erythematosus and glomerulonephritis. (abnova.com)
Introduction: Complement mannan-binding lectin (MBL) deficiency is associated with increased susceptibility to infections and autoimmune diseases. (endocrine-abstracts.org)

18 Genetic or pharmacologic blockade of the complement pathway can prevent synaptic stripping and alleviate multiple age- and inflammation-related disorders. (nature.com)
The prototypic long PTX, PTX3, and the first component of the classical complement pathway, C1q, are innate opsonins involved in the disposal of dying cells by phagocytes. (elsevier.com)
Defects in either the complement pathway or follicular dendritic cells result in resistance to peripheral scrapie infection ( 7 , 8 ), and this resistance likely occurs for peripheral transmissible spongiform encephalopathy infections in general. (cdc.gov)
Usually, C1q activates the classical pathway by binding to IgG-antigen complexes. (frontiersin.org)
Not only did we show that the classical cascade mediated synapse pruning, we showed that the classical complement pathway became reactivated again as the earliest sign of pathology in the neurodegenerative disease glaucoma. (alzforum.org)
The researchers provide further evidence for the role of C3 and complement in neuronal function and dysfunction in Alzheimer's disease as well as the complement pathway as a potential therapeutic target in AD and other neurodegenerative diseases. (alzforum.org)
Mannan-binding lectin (MBL) and MBL-associated serine proteases (MASPs) are involved in the initial step of the lectin pathway of complement activation. (abcam.com)
Following these cleavage events, complement pathway activation continues as in the classical pathway. (abcam.com)
One unit of whole alternative pathway activity (APH50) is defined as the input of C9-Dpl, reconstituted with C9, or NHS Complement Standard yielding 50% lysis of 1.5 x 10⁷ rabbit erythrocytes when incubated for 30 min at 37°C in a total reaction volume of 75 µl GVB° containing a final Mg-EGTA concentration of 13.3 mM. (emdmillipore.com)
2006) Roles of the Alternative Complement Pathway and C1q during Innate Immunity to Streptococcus pyogenes . (emdmillipore.com)
Complement factor C1 q is part of a classic immune pathway that functions peripherally to tag and remove infectious agents and cellular debris from circulation. (cuni.cz)
The clinical history of patients with classic pathway deficiencies varies slightly from other complement-deficient patients. (medscape.com)

Anti-C1q autoantibodies are linked to autoimmune thyroid disorders in pregnant women. (endocrine-abstracts.org)
Background: Autoantibodies directed against complement C1q (anti-C1q) have been described in a number of systemic autoimmune disorders. (endocrine-abstracts.org)
However, no study has focused on the presence of anti-C1q in organ specific autoimmune disorders. (endocrine-abstracts.org)
The aim of this study was to determine the prevalence of anti-C1q in autoimmune thyroid disorders (AITD).Methods: Serum levels. (endocrine-abstracts.org)
Patients with SEL (97 females and 13 males) were studied and the following parameters were obtained on all: SLE disease activity index (SLEDAI), anti-C1q, anti-ds DNA and C3. (who.int)
The positive predictive values of anti-C1q and anti-ds DNA for lupus nephritis were 59 and 61 per cent respectively. (who.int)
No significant correlation was observed between anti-C1q positivity and any particular organ involvement. (who.int)
Similarly, no correlation was found between anti-C1q and proliferative lupus nephritis. (who.int)
anti-C1q vasculitis) in two Idiopathic Angioedema and Urticarial Vasculitis in a Patient with a History of Acquired Haemophilia. (web.app)

We show here that characterized Toll-like receptor (TLR) ligands elicit the production of C1q and PTX3 by immature dendritic cells (DC). (elsevier.com)
That requires synaptic C1q binding and then activation of the cascade leading to deposition of C3b on synapses, which are then eliminated by microglial phagocytosis, the latter being mediated by the microglial C3b receptor called CD11b. (alzforum.org)

have done is to show that pharmacological blockade of the complement system is therapeutic in mouse models of Alzheimer's. (alzforum.org)

We further determined that neuronal Nr4a1 signaling was essential for attracting C1q synaptic deposition and subsequent microglia-mediated synaptic elimination. (nature.com)
Tissue C3 deposition in C1q KO and WT, but not C2/fB KO, mice after GI/R demonstrated that complement was activated in C1q KO mice. (aai.org)
PTX3 binds in the fluid phase to C1q, decreasing C1q deposition and subsequent complement activation on apoptotic cells. (elsevier.com)

C1q associates with C1r and C1s in order to yield the first component of the serum complement system. (abnova.com)

Complement activation plays an important role in local and remote tissue injury associated with gastrointestinal ischemia-reperfusion (GI/R). The role of the classical and lectin complement pathways in GI/R injury was evaluated using C1q-deficient (C1q KO), MBL-A/C-deficient (MBL-null), complement factor 2- and factor B-deficient (C2/fB KO), and wild-type (WT) mice. (aai.org)
Therefore, when C3 is cleaved upon complement activation, the C3a fragment does not bind to the synapse, rather it is a chemotactic factor that helps recruit microglia to eat the synapse. (alzforum.org)
Learn about the three pathways lead to complement activation and some of their key inhibitors. (abcam.com)
T. gondii exposure and complement activation have both been implicated in the development of complex brain disorders such as schizophrenia. (cuni.cz)
Activation of complement C1q and C3 in glomeruli might accelerate the progression of diabetic nephropathy: Evidence from transcriptomic data and renal histopathology. (cdc.gov)

We identified one previously reported homozygous nonsense mutation in the C1QC (Complement C1q C Chain) gene, which explains the immunodeficiency and severe SLE phenotype of that patient. (lu.se)

Senescence of the immune system function could interfere with transmissible spongiform encephalopathy pathogenesis in other ways as well, such as impairing migrating intestinal dendritic cells or complement pathways involved in complexing PrP Res to follicular dendritic cells. (cdc.gov)

Human C1q is a collagen-like hexametric glycoprotein whose structure is similar to that of a flower, possessing six collagen-like "stalks" linked between six globular "heads" as well as a fibril-like central region ( 9 ). (frontiersin.org)
C1q has two classical cell surface receptors (C1qRs): cC1qR binds to the collagen "stalks" tail, whereas gC1qR binds to the globular "heads" ( 11 ). (frontiersin.org)
it has a collagen-like domain structurally homologous with collagen VIII and X and complement factor C1q-like globular domain. (biovendor.com)

It had already been long known that classical complement cascade is profoundly overactivated in Alzheimer's disease brains. (alzforum.org)
So Beth and I proposed that C1q and the classical complement cascade would be a universal driver of synapse loss in many neurodegenerative diseases, including Alzheimer's. (alzforum.org)
I became so enthusiastic about this that four years ago I co-founded a company, Annexon Biosciences, that has made the first therapeutic that targets C1q and blocks the classical complement cascade. (alzforum.org)
have now provided further direct evidence for a role of the complement cascade component C3 in driving synapse loss in mouse models of Alzheimer's. (alzforum.org)
Because there are not yet any good drugs to block the classical complement cascade, they could only test an already-established C3aR blocking drug. (alzforum.org)
The problem with this approach is that it is very indirect, because C3aR is not required for the classical complement cascade to mediate synapse loss. (alzforum.org)
I think the critical question now is whether direct pharmacological blockers of C1q and the classical complement cascade will be neuroprotective. (alzforum.org)
The "complement cascade" is a series of reactions that take place in the blood. (medlineplus.gov)
C1 is the first molecule in the classical complement cascade and comprises C1q and two molecules of C1r and C1s respectively. (abcam.com)

The functions of complement include the attraction of inflammatory cells, opsonization to promote phagocytosis, immune complex clearance and direct microbial killing through the formation of the membrane attack complex (MAC). (abcam.com)

C1q is composed of 18 polypeptide chains: six A-chains, six B-chains, and six C-chains. (abnova.com)

The complement system, a component of the innate immune system, has traditionally been considered to be an ancient defense mechanism that resists a broad range of invasive pathogens. (frontiersin.org)
The complement system is a heat-labile component of blood that confers bactericidal properties. (abcam.com)
Human serum depleted of complement component C9 by affinity chromatography. (emdmillipore.com)
Predicted to enable complement component C1q complex binding activity. (zfin.org)
The first component of complement, C1, is a calcium-dependent complex of the 3 subcomponents C1q, C1r, and C1s. (ptglab.com)
The defect in persons with Leiner disease is usually attributed to a defect of the fifth component of complement (C5). (medscape.com)
However, a child was described by Sonea and associates who had Leiner disease associated with diminished C3, and another was described by Goodyear and Harper with a low level of the fourth component of complement and reduced neutrophil mobility. (medscape.com)

Moreover, PTX3 inhibited the cross-presentation of the MELAN-A/melanoma antigen-reactive T cell 1 (MART-1) tumor antigen expressed by dying cells, even in the presence of C1q. (elsevier.com)
In summary, gC1qR suppressed the MM-inhibiting role of C1q and regulated CKS1B mRNA in promoting tumor proliferation via IGF2BP3 in 1q21-amplified MM. Our findings provide novel evidence on how MM cells evade the immune system and promote survival as well as suggest possible novel targets for future therapies of MM. (frontiersin.org)
In this study, we investigated the mechanisms by which complement C5a increases the capacity of polymorphonuclear MDSCs (PMN-MDSCs) to promote tumor growth and metastatic spread. (unav.edu)
Candidate genes included those within the bovine Major Histocompatability Complex such as BoLA-DQ, BoLA-DR and the non-classical BoLA-NC1 for AMIR and BoLA-DQ for CMIR, the complement system including C2 and C4 for AMIR and C1q for CMIR, and cytokines including IL-17A, IL17F for AMIR and IL-17RA for CMIR and tumor necrosis factor for both AMIR and CMIR. (biomedcentral.com)

In the lupus brain, C1q was increased and localized at synaptic terminals, causing the apposition of phagocytic microglia and ensuing synaptic engulfment. (nature.com)
Our findings revealed an active role of neurons in coordinating microglia-mediated synaptic loss and highlighted neuronal Nr4a1 and C1q as critical components amenable to therapeutic intervention in NPSLE. (nature.com)
18 , 19 Despite mounting evidence that C1q assists in microglial synapse stripping, the major source of C1q is not clear, nor is how C1q cooperates with microglia to orchestrate synaptic pruning. (nature.com)

Here, we show that complement-coordinated elimination of synapses participated in NPSLE in MRL/lpr mice, a lupus-prone murine model. (nature.com)

A summary of the complement system. (lookfordiagnosis.com)
of bacteria) in order to activate the complement system via the C1Q complex. (lookfordiagnosis.com)
Pentraxins (PTX) and complement belong to the humoral arm of the innate immune system and have essential functions in immune defense to microbes and in scavenging cellular debris. (elsevier.com)
Few studies focus on the immunomodulatory effects of the complement system on MM. This study aims to explore the role of C1q in MM patients. (frontiersin.org)
However, few studies actually focus on the immunomodulatory effects of the complement system on MM. (frontiersin.org)
However, pertinent data have recognized that C1q possesses various independent functions associated with cancer progression that are not directly related to the complement system ( 10 ). (frontiersin.org)
Total complement activity (CH50, CH100) looks at the overall activity of the complement system. (medlineplus.gov)
This innovative medication is administered intravenously (IV) and is meant to suppress C1q and the complete classical complement system. (grandviewresearch.com)

with microglia and sick neurons both making C1q. (alzforum.org)

Additionally, gC1qR was noted to suppress the MM-inhibiting role of C1q in H929, U266, and MM1S. (frontiersin.org)

Our data preliminarily suggest that this complement activity may aid in the clearance of this parasite from the CNS and in so doing, have consequences for the connectivity of neighboring cells and synapses. (cuni.cz)

Thyroid hormones regulate the production of complement mannan-binding lectin regardless of the MBL2 genotype: a cohort study of 95 patients with autoimmune thyroid disorders. (endocrine-abstracts.org)

determine the expression pattern of C1q in peripheral blood mononuclear cells (PBMCs) to explore the function of C1q in TB, finding that C1q is closely related to the active disease and disease severity in TB and serves as a diagnostic biomarker for the disease [ 18 ]. (hindawi.com)

The coordinated induction by primary, proinflammatory signals of C1q and PTX3 and their reciprocal regulation during inflammation influences the clearance of apoptotic cells by antigen-presenting cells and possibly plays a role in immune homeostasis. (elsevier.com)
C1q immune complex detection - serum. (medlineplus.gov)
The 3 major sequelae of complement deficiencies, based on the pathophysiology of each defect, are (1) defects that result in inadequate opsonization, (2) defects in cell lysis, and (3) the association of complement deficiencies with immune complex diseases. (medscape.com)

GI/R significantly increased serum alanine aminotransferase, gastrointestinal barrier dysfunction, and neutrophil infiltration into the lung and gut in C1q KO and WT, but not C2/fB KO, mice. (aai.org)

Gastrointestinal ischemia (20 min), followed by 3-h reperfusion, induced intestinal and lung injury in C1q KO and WT mice, but not in C2/fB KO mice. (aai.org)

Ram S. Complement and deficiencies. (medlineplus.gov)

These results suggest that interaction of C1q and PTX3 influences the clearance of apoptotic cells by DC. (elsevier.com)

Bean KV, Massey D, Gupta G. Mediators of inflammation: complement. (medlineplus.gov)

Plasma C1q was found to be significantly reduced in MM patients, and the amount of C1q deposited around the CD138 + cells in bone marrow (BM) biopsy sections was observed to be much higher, especially in the subgroup with 1q21 amplification (Amp1q21). (frontiersin.org)

CD138 + cells expressed higher levels of C1q receptors (C1qRs) than CD138 − cells. (frontiersin.org)

This article describes the test that measures total complement activity. (medlineplus.gov)
Complement activity varies throughout the body. (medlineplus.gov)
For example, in people with rheumatoid arthritis , complement activity in the blood may be normal or higher-than-normal, but much lower-than-normal in the joint fluid. (medlineplus.gov)

Anatomy7

Organisms4

Diseases6

Chemicals and Drugs65

Analytical, Diagnostic and Therapeutic Techniques and Equipment6

Phenomena and Processes14

Information Science3

C1qRP is a heavily O-glycosylated cell surface protein involved in the regulation of phagocytic activity. (1/737)

Alzheimer's beta-amyloid peptides can activate the early components of complement classical pathway in a C1q-independent manner. (2/737)

C1q binding to liposomes is surface charge dependent and is inhibited by peptides consisting of residues 14-26 of the human C1qA chain in a sequence independent manner. (3/737)

Cutting edge: C1q protects against the development of glomerulonephritis independently of C3 activation. (4/737)

EMILIN, a component of the elastic fiber and a new member of the C1q/tumor necrosis factor superfamily of proteins. (5/737)

Antibody-independent classical complement pathway activation and homologous C3 deposition in xeroderma pigmentosum cell lines. (6/737)

Neuronal protection in stroke by an sLex-glycosylated complement inhibitory protein. (7/737)

Role of complement component C1q in the IgG-independent opsonophagocytosis of group B streptococcus. (8/737)

Complement C3

Complement C4

Complement C4a

Complement C1q

Complement C3a

Complement C5a

Complement Activation

Complement C4b

Complement C5

Complement C3b

Complement System Proteins

Complement C6

Complement C3c

Complement C3d

Complement C2

Complement C9

Receptors, Complement

Complement C1s

Complement Membrane Attack Complex

Complement C1r

Complement Inactivator Proteins

Complement C7

Complement C3-C5 Convertases

Complement Factor B

Complement Pathway, Alternative

Complement Pathway, Classical

Complement C8

Complement C1

Receptors, Complement 3b

Complement Factor H

Complement C5b

Complement C2a

Receptor, Anaphylatoxin C5a

Complement Activating Enzymes

Complement Inactivating Agents

Complement Hemolytic Activity Assay

Complement C1 Inactivator Proteins

Receptors, Complement 3d

Anaphylatoxins

Complement Fixation Tests

Complement Factor D

Complement Factor I

Complement C4b-Binding Protein

Complement C3b Inactivator Proteins

Antigens, CD55

Complement C3-C5 Convertases, Classical Pathway

Complement C2b

Antigens, CD59

Cobra Venoms

Antigen-Antibody Complex

Steroid 21-Hydroxylase

Complement C3-C5 Convertases, Alternative Pathway

Molecular Sequence Data

Complement C1 Inhibitor Protein

Hemolysis

Immunoglobulin G

Complement C3 Convertase, Alternative Pathway

Complement C5 Convertase, Classical Pathway

Complement C3 Convertase, Classical Pathway

Antigens, CD46

Opsonin Proteins

Blood Proteins

Lupus Erythematosus, Systemic

Amino Acid Sequence

Complement C5 Convertase, Alternative Pathway

Phagocytosis

Complement Pathway, Mannose-Binding Lectin

Properdin

Complement C5a, des-Arginine

Base Sequence

Protein Binding

Mice, Inbred C57BL

Macrophage-1 Antigen

Neutrophils

Kidney Glomerulus

Serum

Glomerulonephritis, Membranoproliferative

Immunoglobulin M

Genetic Complementation Test

Enzyme-Linked Immunosorbent Assay