Complement C3: A glycoprotein that is central in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C3 can be cleaved into COMPLEMENT C3A and COMPLEMENT C3B, spontaneously at low level or by C3 CONVERTASE at high level. The smaller fragment C3a is an ANAPHYLATOXIN and mediator of local inflammatory process. The larger fragment C3b binds with C3 convertase to form C5 convertase.Complement C4: A glycoprotein that is important in the activation of CLASSICAL COMPLEMENT PATHWAY. C4 is cleaved by the activated COMPLEMENT C1S into COMPLEMENT C4A and COMPLEMENT C4B.Complement C4a: The smaller fragment formed when complement C4 is cleaved by COMPLEMENT C1S. It is an anaphylatoxin that causes symptoms of immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE) but its activity is weaker than that of COMPLEMENT C3A or COMPLEMENT C5A.Complement C3a: The smaller fragment generated from the cleavage of complement C3 by C3 CONVERTASE. C3a, a 77-amino acid peptide, is a mediator of local inflammatory process. It induces smooth MUSCLE CONTRACTION, and HISTAMINE RELEASE from MAST CELLS and LEUKOCYTES. C3a is considered an anaphylatoxin along with COMPLEMENT C4A; COMPLEMENT C5A; and COMPLEMENT C5A, DES-ARGININE.Complement C1q: A subcomponent of complement C1, composed of six copies of three polypeptide chains (A, B, and C), each encoded by a separate gene (C1QA; C1QB; C1QC). This complex is arranged in nine subunits (six disulfide-linked dimers of A and B, and three disulfide-linked homodimers of C). C1q has binding sites for antibodies (the heavy chain of IMMUNOGLOBULIN G or IMMUNOGLOBULIN M). The interaction of C1q and immunoglobulin activates the two proenzymes COMPLEMENT C1R and COMPLEMENT C1S, thus initiating the cascade of COMPLEMENT ACTIVATION via the CLASSICAL COMPLEMENT PATHWAY.Complement Activation: The sequential activation of serum COMPLEMENT PROTEINS to create the COMPLEMENT MEMBRANE ATTACK COMPLEX. Factors initiating complement activation include ANTIGEN-ANTIBODY COMPLEXES, microbial ANTIGENS, or cell surface POLYSACCHARIDES.Complement C5a: The minor fragment formed when C5 convertase cleaves C5 into C5a and COMPLEMENT C5B. C5a is a 74-amino-acid glycopeptide with a carboxy-terminal ARGININE that is crucial for its spasmogenic activity. Of all the complement-derived anaphylatoxins, C5a is the most potent in mediating immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE), smooth MUSCLE CONTRACTION; HISTAMINE RELEASE; and migration of LEUKOCYTES to site of INFLAMMATION.Antibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).Complement C4b: The large fragment formed when COMPLEMENT C4 is cleaved by COMPLEMENT C1S. The membrane-bound C4b binds COMPLEMENT C2A, a SERINE PROTEASE, to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).Complement C5: C5 plays a central role in both the classical and the alternative pathway of COMPLEMENT ACTIVATION. C5 is cleaved by C5 CONVERTASE into COMPLEMENT C5A and COMPLEMENT C5B. The smaller fragment C5a is an ANAPHYLATOXIN and mediator of inflammatory process. The major fragment C5b binds to the membrane initiating the spontaneous assembly of the late complement components, C5-C9, into the MEMBRANE ATTACK COMPLEX.Complement C3b: The larger fragment generated from the cleavage of COMPLEMENT C3 by C3 CONVERTASE. It is a constituent of the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb), and COMPLEMENT C5 CONVERTASES in both the classical (C4b2a3b) and the alternative (C3bBb3b) pathway. C3b participates in IMMUNE ADHERENCE REACTION and enhances PHAGOCYTOSIS. It can be inactivated (iC3b) or cleaved by various proteases to yield fragments such as COMPLEMENT C3C; COMPLEMENT C3D; C3e; C3f; and C3g.Complement System Proteins: Serum glycoproteins participating in the host defense mechanism of COMPLEMENT ACTIVATION that creates the COMPLEMENT MEMBRANE ATTACK COMPLEX. Included are glycoproteins in the various pathways of complement activation (CLASSICAL COMPLEMENT PATHWAY; ALTERNATIVE COMPLEMENT PATHWAY; and LECTIN COMPLEMENT PATHWAY).Complement C6: A 105-kDa serum glycoprotein with significant homology to the other late complement components, C7-C9. It is a polypeptide chain cross-linked by 32 disulfide bonds. C6 is the next complement component to bind to the membrane-bound COMPLEMENT C5B in the assembly of MEMBRANE ATTACK COMPLEX. It is encoded by gene C6.Complement C3c: A 206-amino-acid fragment in the alpha chain (672-1663) of C3b. It is generated when C3b is inactivated (iC3b) and its alpha chain is cleaved by COMPLEMENT FACTOR I into C3c (749-954), and C3dg (955-1303) in the presence COMPLEMENT FACTOR H.Complement C3d: A 302-amino-acid fragment in the alpha chain (672-1663) of C3b. It is generated when C3b is inactivated (iC3b) and its alpha chain is cleaved by COMPLEMENT FACTOR I into C3c, and C3dg (955-1303) in the presence COMPLEMENT FACTOR H. Serum proteases further degrade C3dg into C3d (1002-1303) and C3g (955-1001).Complement C2: A component of the CLASSICAL COMPLEMENT PATHWAY. C2 is cleaved by activated COMPLEMENT C1S into COMPLEMENT C2B and COMPLEMENT C2A. C2a, the COOH-terminal fragment containing a SERINE PROTEASE, combines with COMPLEMENT C4B to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).Complement C9: A 63-kDa serum glycoprotein encoded by gene C9. Monomeric C9 (mC9) binds the C5b-8 complex to form C5b-9 which catalyzes the polymerization of C9 forming C5b-p9 (MEMBRANE ATTACK COMPLEX) and transmembrane channels leading to lysis of the target cell. Patients with C9 deficiency suffer from recurrent bacterial infections.Receptors, Complement: Molecules on the surface of some B-lymphocytes and macrophages, that recognize and combine with the C3b, C3d, C1q, and C4b components of complement.Complement C1s: A 77-kDa subcomponent of complement C1, encoded by gene C1S, is a SERINE PROTEASE existing as a proenzyme (homodimer) in the intact complement C1 complex. Upon the binding of COMPLEMENT C1Q to antibodies, the activated COMPLEMENT C1R cleaves C1s into two chains, A (heavy) and B (light, the serine protease), linked by disulfide bonds yielding the active C1s. The activated C1s, in turn, cleaves COMPLEMENT C2 and COMPLEMENT C4 to form C4b2a (CLASSICAL C3 CONVERTASE).Antibody Specificity: The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.Complement Membrane Attack Complex: A product of COMPLEMENT ACTIVATION cascade, regardless of the pathways, that forms transmembrane channels causing disruption of the target CELL MEMBRANE and cell lysis. It is formed by the sequential assembly of terminal complement components (COMPLEMENT C5B; COMPLEMENT C6; COMPLEMENT C7; COMPLEMENT C8; and COMPLEMENT C9) into the target membrane. The resultant C5b-8-poly-C9 is the "membrane attack complex" or MAC.Complement C1r: A 80-kDa subcomponent of complement C1, existing as a SERINE PROTEASE proenzyme in the intact complement C1 complex. When COMPLEMENT C1Q is bound to antibodies, the changed tertiary structure causes autolytic activation of complement C1r which is cleaved into two chains, A (heavy) and B (light, the serine protease), connected by disulfide bonds. The activated C1r serine protease, in turn, activates COMPLEMENT C1S proenzyme by cleaving the Arg426-Ile427 bond. No fragment is released when either C1r or C1s is cleaved.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.Complement Inactivator Proteins: Serum proteins that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host. The complement system is tightly regulated by inactivators that accelerate the decay of intermediates and certain cell surface receptors.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Complement C7: A 93-kDa serum glycoprotein encoded by C7 gene. It is a polypeptide chain with 28 disulfide bridges. In the formation of MEMBRANE ATTACK COMPLEX; C7 is the next component to bind the C5b-6 complex forming a trimolecular complex C5b-7 which is lipophilic, resembles an integral membrane protein, and serves as an anchor for the late complement components, C8 and C9.Complement C3-C5 Convertases: Serine proteases that cleave COMPLEMENT C3 into COMPLEMENT C3A and COMPLEMENT C3B, or cleave COMPLEMENT C5 into COMPLEMENT C5A and COMPLEMENT C5B. These include the different forms of C3/C5 convertases in the classical and the alternative pathways of COMPLEMENT ACTIVATION. Both cleavages take place at the C-terminal of an ARGININE residue.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Complement Pathway, Alternative: Complement activation initiated by the interaction of microbial ANTIGENS with COMPLEMENT C3B. When COMPLEMENT FACTOR B binds to the membrane-bound C3b, COMPLEMENT FACTOR D cleaves it to form alternative C3 CONVERTASE (C3BBB) which, stabilized by COMPLEMENT FACTOR P, is able to cleave multiple COMPLEMENT C3 to form alternative C5 CONVERTASE (C3BBB3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.Complement Factor B: A glycine-rich, heat-labile serum glycoprotein that contains a component of the C3 CONVERTASE ALTERNATE PATHWAY (C3bBb). Bb, a serine protease, is generated when factor B is cleaved by COMPLEMENT FACTOR D into Ba and Bb.Complement Pathway, Classical: Complement activation initiated by the binding of COMPLEMENT C1 to ANTIGEN-ANTIBODY COMPLEXES at the COMPLEMENT C1Q subunit. This leads to the sequential activation of COMPLEMENT C1R and COMPLEMENT C1S subunits. Activated C1s cleaves COMPLEMENT C4 and COMPLEMENT C2 forming the membrane-bound classical C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and the assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.Complement C8: A 150-kDa serum glycoprotein composed of three subunits with each encoded by a different gene (C8A; C8B; and C8G). This heterotrimer contains a disulfide-linked C8alpha-C8gamma heterodimer and a noncovalently associated C8beta chain. C8 is the next component to bind the C5-7 complex forming C5b-8 that binds COMPLEMENT C9 and acts as a catalyst in the polymerization of C9.Complement C1: The first complement component to act in the activation of CLASSICAL COMPLEMENT PATHWAY. It is a calcium-dependent trimolecular complex made up of three subcomponents: COMPLEMENT C1Q; COMPLEMENT C1R; and COMPLEMENT C1S at 1:2:2 ratios. When the intact C1 binds to at least two antibodies (involving C1q), C1r and C1s are sequentially activated, leading to subsequent steps in the cascade of COMPLEMENT ACTIVATION.Antibody Formation: The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.Receptors, Complement 3b: Molecular sites on or in some B-lymphocytes and macrophages that recognize and combine with COMPLEMENT C3B. The primary structure of these receptors reveal that they contain transmembrane and cytoplasmic domains, with their extracellular portion composed entirely of thirty short consensus repeats each having 60 to 70 amino acids.Complement Factor H: An important soluble regulator of the alternative pathway of complement activation (COMPLEMENT ACTIVATION PATHWAY, ALTERNATIVE). It is a 139-kDa glycoprotein expressed by the liver and secreted into the blood. It binds to COMPLEMENT C3B and makes iC3b (inactivated complement 3b) susceptible to cleavage by COMPLEMENT FACTOR I. Complement factor H also inhibits the association of C3b with COMPLEMENT FACTOR B to form the C3bB proenzyme, and promotes the dissociation of Bb from the C3bBb complex (COMPLEMENT C3 CONVERTASE, ALTERNATIVE PATHWAY).Antibodies, Neutralizing: Antibodies that reduce or abolish some biological activity of a soluble antigen or infectious agent, usually a virus.Complement C5b: The larger fragment generated from the cleavage of C5 by C5 CONVERTASE that yields COMPLEMENT C5A and C5b (beta chain + alpha' chain, the residual alpha chain, bound by disulfide bond). C5b remains bound to the membrane and initiates the spontaneous assembly of the late complement components to form C5b-8-poly-C9, the MEMBRANE ATTACK COMPLEX.Complement C2a: The COOH-terminal fragment of COMPLEMENT 2, released by the action of activated COMPLEMENT C1S. It is a SERINE PROTEASE. C2a combines with COMPLEMENT C4B to form C4b2a (CLASSICAL PATHWAY C3 CONVERTASE) and subsequent C4b2a3b (CLASSICAL PATHWAY C5 CONVERTASE).Receptor, Anaphylatoxin C5a: A G-protein-coupled receptor that signals an increase in intracellular calcium in response to the potent ANAPHYLATOXIN peptide COMPLEMENT C5A.Complement Activating Enzymes: Enzymes that activate one or more COMPLEMENT PROTEINS in the complement system leading to the formation of the COMPLEMENT MEMBRANE ATTACK COMPLEX, an important response in host defense. They are enzymes in the various COMPLEMENT ACTIVATION pathways.Complement Hemolytic Activity Assay: A screening assay for circulating COMPLEMENT PROTEINS. Diluted SERUM samples are added to antibody-coated ERYTHROCYTES and the percentage of cell lysis is measured. The values are expressed by the so called CH50, in HEMOLYTIC COMPLEMENT units per milliliter, which is the dilution of serum required to lyse 50 percent of the erythrocytes in the assay.Complement Inactivating Agents: Compounds that negatively regulate the cascade process of COMPLEMENT ACTIVATION. Uncontrolled complement activation and resulting cell lysis is potentially dangerous for the host.Complement Fixation Tests: Serologic tests based on inactivation of complement by the antigen-antibody complex (stage 1). Binding of free complement can be visualized by addition of a second antigen-antibody system such as red cells and appropriate red cell antibody (hemolysin) requiring complement for its completion (stage 2). Failure of the red cells to lyse indicates that a specific antigen-antibody reaction has taken place in stage 1. If red cells lyse, free complement is present indicating no antigen-antibody reaction occurred in stage 1.Receptors, Complement 3d: Molecular sites on or in B-lymphocytes, follicular dendritic cells, lymphoid cells, and epithelial cells that recognize and combine with COMPLEMENT C3D. Human complement receptor 2 (CR2) serves as a receptor for both C3dg and the gp350/220 glycoprotein of HERPESVIRUS 4, HUMAN, and binds the monoclonal antibody OKB7, which blocks binding of both ligands to the receptor.Complement C1 Inactivator Proteins: Serum proteins that inhibit, antagonize, or inactivate COMPLEMENT C1 or its subunits.Fluorescent Antibody Technique: Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.Antibody Affinity: A measure of the binding strength between antibody and a simple hapten or antigen determinant. It depends on the closeness of stereochemical fit between antibody combining sites and antigen determinants, on the size of the area of contact between them, and on the distribution of charged and hydrophobic groups. It includes the concept of "avidity," which refers to the strength of the antigen-antibody bond after formation of reversible complexes.Anaphylatoxins: Serum peptides derived from certain cleaved COMPLEMENT PROTEINS during COMPLEMENT ACTIVATION. They induce smooth MUSCLE CONTRACTION; mast cell HISTAMINE RELEASE; PLATELET AGGREGATION; and act as mediators of the local inflammatory process. The order of anaphylatoxin activity from the strongest to the weakest is C5a, C3a, C4a, and C5a des-arginine.Binding Sites, Antibody: Local surface sites on antibodies which react with antigen determinant sites on antigens (EPITOPES.) They are formed from parts of the variable regions of FAB FRAGMENTS.Antigen-Antibody Complex: The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Antibodies, Anti-Idiotypic: Antibodies which react with the individual structural determinants (idiotopes) on the variable region of other antibodies.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.Antibodies, Antinuclear: Autoantibodies directed against various nuclear antigens including DNA, RNA, histones, acidic nuclear proteins, or complexes of these molecular elements. Antinuclear antibodies are found in systemic autoimmune diseases including systemic lupus erythematosus, Sjogren's syndrome, scleroderma, polymyositis, and mixed connective tissue disease.Immunoglobulin M: A class of immunoglobulin bearing mu chains (IMMUNOGLOBULIN MU-CHAINS). IgM can fix COMPLEMENT. The name comes from its high molecular weight and originally being called a macroglobulin.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Complement Factor D: A serum protein which is important in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. This enzyme cleaves the COMPLEMENT C3B-bound COMPLEMENT FACTOR B to form C3bBb which is ALTERNATIVE PATHWAY C3 CONVERTASE.Epitopes: Sites on an antigen that interact with specific antibodies.Autoantibodies: Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.HIV Antibodies: Antibodies reactive with HIV ANTIGENS.Complement Factor I: A plasma serine proteinase that cleaves the alpha-chains of C3b and C4b in the presence of the cofactors COMPLEMENT FACTOR H and C4-binding protein, respectively. It is a 66-kDa glycoprotein that converts C3b to inactivated C3b (iC3b) followed by the release of two fragments, C3c (150-kDa) and C3dg (41-kDa). It was formerly called KAF, C3bINF, or enzyme 3b inactivator.Antibodies, Neoplasm: Immunoglobulins induced by antigens specific for tumors other than the normally occurring HISTOCOMPATIBILITY ANTIGENS.Antibodies, Protozoan: Immunoglobulins produced in a response to PROTOZOAN ANTIGENS.Complement C4b-Binding Protein: A serum protein that regulates the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It binds as a cofactor to COMPLEMENT FACTOR I which then hydrolyzes the COMPLEMENT C4B in the CLASSICAL PATHWAY C3 CONVERTASE (C4bC2a).Complement C3b Inactivator Proteins: Endogenous proteins that inhibit or inactivate COMPLEMENT C3B. They include COMPLEMENT FACTOR H and COMPLEMENT FACTOR I (C3b/C4b inactivator). They cleave or promote the cleavage of C3b into inactive fragments, and thus are important in the down-regulation of COMPLEMENT ACTIVATION and its cytolytic sequence.Antigens, CD55: GPI-linked membrane proteins broadly distributed among hematopoietic and non-hematopoietic cells. CD55 prevents the assembly of C3 CONVERTASE or accelerates the disassembly of preformed convertase, thus blocking the formation of the membrane attack complex.Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Mice, Inbred BALB CComplement C3-C5 Convertases, Classical Pathway: Important enzymes in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. They cleave COMPLEMENT C3 and COMPLEMENT C5.Complement C2b: The N-terminal fragment of COMPLEMENT 2, released by the action of activated COMPLEMENT C1S.Antigens, CD59: Small glycoproteins found on both hematopoietic and non-hematopoietic cells. CD59 restricts the cytolytic activity of homologous complement by binding to C8 and C9 and blocking the assembly of the membrane attack complex. (From Barclay et al., The Leukocyte Antigen FactsBook, 1993, p234)Lupus Erythematosus, Systemic: A chronic, relapsing, inflammatory, and often febrile multisystemic disorder of connective tissue, characterized principally by involvement of the skin, joints, kidneys, and serosal membranes. It is of unknown etiology, but is thought to represent a failure of the regulatory mechanisms of the autoimmune system. The disease is marked by a wide range of system dysfunctions, an elevated erythrocyte sedimentation rate, and the formation of LE cells in the blood or bone marrow.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Cobra Venoms: Venoms from snakes of the genus Naja (family Elapidae). They contain many specific proteins that have cytotoxic, hemolytic, neurotoxic, and other properties. Like other elapid venoms, they are rich in enzymes. They include cobramines and cobralysins.Neutralization Tests: The measurement of infection-blocking titer of ANTISERA by testing a series of dilutions for a given virus-antiserum interaction end-point, which is generally the dilution at which tissue cultures inoculated with the serum-virus mixtures demonstrate cytopathology (CPE) or the dilution at which 50% of test animals injected with serum-virus mixtures show infectivity (ID50) or die (LD50).Enzyme-Linked Immunosorbent Assay: An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.Antibodies, Fungal: Immunoglobulins produced in a response to FUNGAL ANTIGENS.Antigen-Antibody Reactions: The processes triggered by interactions of ANTIBODIES with their ANTIGENS.Hemolysis: The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.Opsonin Proteins: Proteins that bind to particles and cells to increase susceptibility to PHAGOCYTOSIS, especially ANTIBODIES bound to EPITOPES that attach to FC RECEPTORS. COMPLEMENT C3B may also participate.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Steroid 21-Hydroxylase: An adrenal microsomal cytochrome P450 enzyme that catalyzes the 21-hydroxylation of steroids in the presence of molecular oxygen and NADPH-FERRIHEMOPROTEIN REDUCTASE. This enzyme, encoded by CYP21 gene, converts progesterones to precursors of adrenal steroid hormones (CORTICOSTERONE; HYDROCORTISONE). Defects in CYP21 cause congenital adrenal hyperplasia (ADRENAL HYPERPLASIA, CONGENITAL).Complement C3-C5 Convertases, Alternative Pathway: Important enzymes in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. They cleave COMPLEMENT C3 and COMPLEMENT C5.Phagocytosis: The engulfing and degradation of microorganisms; other cells that are dead, dying, or pathogenic; and foreign particles by phagocytic cells (PHAGOCYTES).Mice, Inbred C57BLComplement C1 Inhibitor Protein: An endogenous 105-kDa plasma glycoprotein produced primarily by the LIVER and MONOCYTES. It inhibits a broad spectrum of proteases, including the COMPLEMENT C1R and the COMPLEMENT C1S proteases of the CLASSICAL COMPLEMENT PATHWAY, and the MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. C1-INH-deficient individuals suffer from HEREDITARY ANGIOEDEMA TYPES I AND II.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Complement C3 Convertase, Alternative Pathway: A serine protease that is the complex of COMPLEMENT C3B and COMPLEMENT FACTOR BB. It cleaves multiple COMPLEMENT C3 into COMPLEMENT C3A (anaphylatoxin) and COMPLEMENT C3B in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY.Antibodies, Bispecific: Antibodies, often monoclonal, in which the two antigen-binding sites are specific for separate ANTIGENIC DETERMINANTS. They are artificial antibodies produced by chemical crosslinking, fusion of HYBRIDOMA cells, or by molecular genetic techniques. They function as the main mediators of targeted cellular cytotoxicity and have been shown to be efficient in the targeting of drugs, toxins, radiolabeled haptens, and effector cells to diseased tissue, primarily tumors.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Complement C5 Convertase, Classical Pathway: A serine protease that cleaves multiple COMPLEMENT 5 into COMPLEMENT 5A (anaphylatoxin) and COMPLEMENT 5B in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It is a complex of CLASSICAL PATHWAY C3 CONVERTASE (C4b2a) with an additional COMPLEMENT C3B, or C4b2a3b.Antigens, CD46: A ubiquitously expressed complement receptor that binds COMPLEMENT C3B and COMPLEMENT C4B and serves as a cofactor for their inactivation. CD46 also interacts with a wide variety of pathogens and mediates immune response.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Antibodies, Blocking: Antibodies that inhibit the reaction between ANTIGEN and other antibodies or sensitized T-LYMPHOCYTES (e.g., antibodies of the IMMUNOGLOBULIN G class that compete with IGE antibodies for antigen, thereby blocking an allergic response). Blocking antibodies that bind tumors and prevent destruction of tumor cells by CYTOTOXIC T-LYMPHOCYTES have also been called enhancing antibodies. (Rosen et al., Dictionary of Immunology, 1989)Single-Chain Antibodies: A form of antibodies consisting only of the variable regions of the heavy and light chains (FV FRAGMENTS), connected by a small linker peptide. They are less immunogenic than complete immunoglobulin and thus have potential therapeutic use.Complement C3 Convertase, Classical Pathway: A serine protease that cleaves multiple COMPLEMENT 3 into COMPLEMENT 3A (anaphylatoxin) and COMPLEMENT 3B in the CLASSICAL COMPLEMENT ACTIVATION PATHWAY. It is a complex of COMPLEMENT 4B and COMPLEMENT 2A (C4b2a).Immunoglobulin Fab Fragments: Univalent antigen-binding fragments composed of one entire IMMUNOGLOBULIN LIGHT CHAIN and the amino terminal end of one of the IMMUNOGLOBULIN HEAVY CHAINS from the hinge region, linked to each other by disulfide bonds. Fab contains the IMMUNOGLOBULIN VARIABLE REGIONS, which are part of the antigen-binding site, and the first IMMUNOGLOBULIN CONSTANT REGIONS. This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Antibodies, Heterophile: Antibodies elicited in a different species from which the antigen originated. These antibodies are directed against a wide variety of interspecies-specific antigens, the best known of which are Forssman, Hanganutziu-Deicher (H-D), and Paul-Bunnell (P-B). Incidence of antibodies to these antigens--i.e., the phenomenon of heterophile antibody response--is useful in the serodiagnosis, pathogenesis, and prognosis of infection and latent infectious states as well as in cancer classification.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Immunoglobulin A: Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory IgA (IMMUNOGLOBULIN A, SECRETORY) is the main immunoglobulin in secretions.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Neutrophils: Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.Complement C5 Convertase, Alternative Pathway: A serine protease that cleaves multiple COMPLEMENT C5 into COMPLEMENT C5A (anaphylatoxin) and COMPLEMENT C5B in the ALTERNATIVE COMPLEMENT ACTIVATION PATHWAY. It is the complex of ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb) with an additional COMPLEMENT C3B, or C3bBb3b.Molecular Weight: The sum of the weight of all the atoms in a molecule.Immunoglobulins: Multi-subunit proteins which function in IMMUNITY. They are produced by B LYMPHOCYTES from the IMMUNOGLOBULIN GENES. They are comprised of two heavy (IMMUNOGLOBULIN HEAVY CHAINS) and two light chains (IMMUNOGLOBULIN LIGHT CHAINS) with additional ancillary polypeptide chains depending on their isoforms. The variety of isoforms include monomeric or polymeric forms, and transmembrane forms (B-CELL ANTIGEN RECEPTORS) or secreted forms (ANTIBODIES). They are divided by the amino acid sequence of their heavy chains into five classes (IMMUNOGLOBULIN A; IMMUNOGLOBULIN D; IMMUNOGLOBULIN E; IMMUNOGLOBULIN G; IMMUNOGLOBULIN M) and various subclasses.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Antibodies, Catalytic: Antibodies that can catalyze a wide variety of chemical reactions. They are characterized by high substrate specificity and share many mechanistic features with enzymes.Fluorescent Antibody Technique, Indirect: A form of fluorescent antibody technique commonly used to detect serum antibodies and immune complexes in tissues and microorganisms in specimens from patients with infectious diseases. The technique involves formation of an antigen-antibody complex which is labeled with fluorescein-conjugated anti-immunoglobulin antibody. (From Bennington, Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)B-Lymphocytes: Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Antibodies, Monoclonal, Humanized: Antibodies from non-human species whose protein sequences have been modified to make them nearly identical with human antibodies. If the constant region and part of the variable region are replaced, they are called humanized. If only the constant region is modified they are called chimeric. INN names for humanized antibodies end in -zumab.Antigens: Substances that are recognized by the immune system and induce an immune reaction.Complement Pathway, Mannose-Binding Lectin: Complement activation triggered by the interaction of microbial POLYSACCHARIDES with serum MANNOSE-BINDING LECTIN resulting in the activation of MANNOSE-BINDING PROTEIN-ASSOCIATED SERINE PROTEASES. As in the classical pathway, MASPs cleave COMPLEMENT C4 and COMPLEMENT C2 to form C3 CONVERTASE (C4B2A) and the subsequent C5 CONVERTASE (C4B2A3B) leading to cleavage of COMPLEMENT C5 and assembly of COMPLEMENT MEMBRANE ATTACK COMPLEX.Hybridomas: Cells artificially created by fusion of activated lymphocytes with neoplastic cells. The resulting hybrid cells are cloned and produce pure MONOCLONAL ANTIBODIES or T-cell products, identical to those produced by the immunologically competent parent cell.Antigens, Surface: Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.Antigens, CD: Differentiation antigens residing on mammalian leukocytes. CD stands for cluster of differentiation, which refers to groups of monoclonal antibodies that show similar reactivity with certain subpopulations of antigens of a particular lineage or differentiation stage. The subpopulations of antigens are also known by the same CD designation.Time Factors: Elements of limited time intervals, contributing to particular results or situations.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Kidney Glomerulus: A cluster of convoluted capillaries beginning at each nephric tubule in the kidney and held together by connective tissue.Properdin: A 53-kDa protein that is a positive regulator of the alternate pathway of complement activation (COMPLEMENT ACTIVATION PATHWAY, ALTERNATIVE). It stabilizes the ALTERNATIVE PATHWAY C3 CONVERTASE (C3bBb) and protects it from rapid inactivation, thus facilitating the cascade of COMPLEMENT ACTIVATION and the formation of MEMBRANE ATTACK COMPLEX. Individuals with mutation in the PFC gene exhibit properdin deficiency and have a high susceptibility to infections.Immunization: Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).Macrophage-1 Antigen: An adhesion-promoting leukocyte surface membrane heterodimer. The alpha subunit consists of the CD11b ANTIGEN and the beta subunit the CD18 ANTIGEN. The antigen, which is an integrin, functions both as a receptor for complement 3 and in cell-cell and cell-substrate adhesive interactions.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Serum: The clear portion of BLOOD that is left after BLOOD COAGULATION to remove BLOOD CELLS and clotting proteins.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Immunoenzyme Techniques: Immunologic techniques based on the use of: (1) enzyme-antibody conjugates; (2) enzyme-antigen conjugates; (3) antienzyme antibody followed by its homologous enzyme; or (4) enzyme-antienzyme complexes. These are used histologically for visualizing or labeling tissue specimens.Epitope Mapping: Methods used for studying the interactions of antibodies with specific regions of protein antigens. Important applications of epitope mapping are found within the area of immunochemistry.Complement C5a, des-Arginine: A derivative of complement C5a, generated when the carboxy-terminal ARGININE is removed by CARBOXYPEPTIDASE B present in normal human serum. C5a des-Arg shows complete loss of spasmogenic activity though it retains some chemotactic ability (CHEMOATTRACTANTS).Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.Glomerulonephritis: Inflammation of the renal glomeruli (KIDNEY GLOMERULUS) that can be classified by the type of glomerular injuries including antibody deposition, complement activation, cellular proliferation, and glomerulosclerosis. These structural and functional abnormalities usually lead to HEMATURIA; PROTEINURIA; HYPERTENSION; and RENAL INSUFFICIENCY.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Antibodies, Antiphospholipid: Autoantibodies directed against phospholipids. These antibodies are characteristically found in patients with systemic lupus erythematosus (LUPUS ERYTHEMATOSUS, SYSTEMIC;), ANTIPHOSPHOLIPID SYNDROME; related autoimmune diseases, some non-autoimmune diseases, and also in healthy individuals.Immune Sera: Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.Flow Cytometry: Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.Immunization, Passive: Transfer of immunity from immunized to non-immune host by administration of serum antibodies, or transplantation of lymphocytes (ADOPTIVE TRANSFER).Macrophages: The relatively long-lived phagocytic cell of mammalian tissues that are derived from blood MONOCYTES. Main types are PERITONEAL MACROPHAGES; ALVEOLAR MACROPHAGES; HISTIOCYTES; KUPFFER CELLS of the liver; and OSTEOCLASTS. They may further differentiate within chronic inflammatory lesions to EPITHELIOID CELLS or may fuse to form FOREIGN BODY GIANT CELLS or LANGHANS GIANT CELLS. (from The Dictionary of Cell Biology, Lackie and Dow, 3rd ed.)Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Kinetics: The rate dynamics in chemical or physical systems.Immunoglobulin Fragments: Partial immunoglobulin molecules resulting from selective cleavage by proteolytic enzymes or generated through PROTEIN ENGINEERING techniques.Glomerulonephritis, Membranoproliferative: Chronic glomerulonephritis characterized histologically by proliferation of MESANGIAL CELLS, increase in the MESANGIAL EXTRACELLULAR MATRIX, and a thickening of the glomerular capillary walls. This may appear as a primary disorder or secondary to other diseases including infections and autoimmune disease SYSTEMIC LUPUS ERYTHEMATOSUS. Various subtypes are classified by their abnormal ultrastructures and immune deposits. Hypocomplementemia is a characteristic feature of all types of MPGN.Bacterial Proteins: Proteins found in any species of bacterium.Major Histocompatibility Complex: The genetic region which contains the loci of genes which determine the structure of the serologically defined (SD) and lymphocyte-defined (LD) TRANSPLANTATION ANTIGENS, genes which control the structure of the IMMUNE RESPONSE-ASSOCIATED ANTIGENS, HUMAN; the IMMUNE RESPONSE GENES which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement.Immunoassay: A technique using antibodies for identifying or quantifying a substance. Usually the substance being studied serves as antigen both in antibody production and in measurement of antibody by the test substance.Antigens, Viral: Substances elaborated by viruses that have antigenic activity.Immunodiffusion: Technique involving the diffusion of antigen or antibody through a semisolid medium, usually agar or agarose gel, with the result being a precipitin reaction.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Hemagglutination Tests: Sensitive tests to measure certain antigens, antibodies, or viruses, using their ability to agglutinate certain erythrocytes. (From Stedman, 26th ed)Surface Plasmon Resonance: A biosensing technique in which biomolecules capable of binding to specific analytes or ligands are first immobilized on one side of a metallic film. Light is then focused on the opposite side of the film to excite the surface plasmons, that is, the oscillations of free electrons propagating along the film's surface. The refractive index of light reflecting off this surface is measured. When the immobilized biomolecules are bound by their ligands, an alteration in surface plasmons on the opposite side of the film is created which is directly proportional to the change in bound, or adsorbed, mass. Binding is measured by changes in the refractive index. The technique is used to study biomolecular interactions, such as antigen-antibody binding.Blood Bactericidal Activity: The natural bactericidal property of BLOOD due to normally occurring antibacterial substances such as beta lysin, leukin, etc. This activity needs to be distinguished from the bactericidal activity contained in a patient's serum as a result of antimicrobial therapy, which is measured by a SERUM BACTERICIDAL TEST.Genetic Complementation Test: A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.Schistosoma: A genus of trematode flukes belonging to the family Schistosomatidae. There are over a dozen species. These parasites are found in man and other mammals. Snails are the intermediate hosts.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Biological Markers: Measurable and quantifiable biological parameters (e.g., specific enzyme concentration, specific hormone concentration, specific gene phenotype distribution in a population, presence of biological substances) which serve as indices for health- and physiology-related assessments, such as disease risk, psychiatric disorders, environmental exposure and its effects, disease diagnosis, metabolic processes, substance abuse, pregnancy, cell line development, epidemiologic studies, etc.Radioimmunoassay: Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.Immunity, Innate: The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring ANTI-INFECTIVE AGENTS, constitutional factors such as BODY TEMPERATURE and immediate acting immune cells such as NATURAL KILLER CELLS.Immunologic Techniques: Techniques used to demonstrate or measure an immune response, and to identify or measure antigens using antibodies.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Hemagglutination Inhibition Tests: Serologic tests in which a known quantity of antigen is added to the serum prior to the addition of a red cell suspension. Reaction result is expressed as the smallest amount of antigen which causes complete inhibition of hemagglutination.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Arteriolosclerosis: Thickening of the walls of small ARTERIES or ARTERIOLES due to cell proliferation or HYALINE deposition.Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Isoantibodies: Antibodies from an individual that react with ISOANTIGENS of another individual of the same species.Peptides, Cyclic: Peptides whose amino and carboxy ends are linked together with a peptide bond forming a circular chain. Some of them are ANTI-INFECTIVE AGENTS. Some of them are biosynthesized non-ribosomally (PEPTIDE BIOSYNTHESIS, NON-RIBOSOMAL).Immunoelectrophoresis: A technique that combines protein electrophoresis and double immunodiffusion. In this procedure proteins are first separated by gel electrophoresis (usually agarose), then made visible by immunodiffusion of specific antibodies. A distinct elliptical precipitin arc results for each protein detectable by the antisera.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Antibody-Dependent Cell Cytotoxicity: The phenomenon of antibody-mediated target cell destruction by non-sensitized effector cells. The identity of the target cell varies, but it must possess surface IMMUNOGLOBULIN G whose Fc portion is intact. The effector cell is a "killer" cell possessing Fc receptors. It may be a lymphocyte lacking conventional B- or T-cell markers, or a monocyte, macrophage, or polynuclear leukocyte, depending on the identity of the target cell. The reaction is complement-independent.Dose-Response Relationship, Immunologic: A specific immune response elicited by a specific dose of an immunologically active substance or cell in an organism, tissue, or cell.HLA Antigens: Antigens determined by leukocyte loci found on chromosome 6, the major histocompatibility loci in humans. They are polypeptides or glycoproteins found on most nucleated cells and platelets, determine tissue types for transplantation, and are associated with certain diseases.Spleen: An encapsulated lymphatic organ through which venous blood filters.Antigens, Neoplasm: Proteins, glycoprotein, or lipoprotein moieties on surfaces of tumor cells that are usually identified by monoclonal antibodies. Many of these are of either embryonic or viral origin.Immunosorbent Techniques: Techniques for removal by adsorption and subsequent elution of a specific antibody or antigen using an immunosorbent containing the homologous antigen or antibody.Immunoglobulin Isotypes: The classes of immunoglobulins found in any species of animal. In man there are nine classes that migrate in five different groups in electrophoresis; they each consist of two light and two heavy protein chains, and each group has distinguishing structural and functional properties.Haptens: Small antigenic determinants capable of eliciting an immune response only when coupled to a carrier. Haptens bind to antibodies but by themselves cannot elicit an antibody response.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Antibodies, Antineutrophil Cytoplasmic: Autoantibodies directed against cytoplasmic constituents of POLYMORPHONUCLEAR LEUKOCYTES and/or MONOCYTES. They are used as specific markers for GRANULOMATOSIS WITH POLYANGIITIS and other diseases, though their pathophysiological role is not clear. ANCA are routinely detected by indirect immunofluorescence with three different patterns: c-ANCA (cytoplasmic), p-ANCA (perinuclear), and atypical ANCA.Lupus Nephritis: Glomerulonephritis associated with autoimmune disease SYSTEMIC LUPUS ERYTHEMATOSUS. Lupus nephritis is histologically classified into 6 classes: class I - normal glomeruli, class II - pure mesangial alterations, class III - focal segmental glomerulonephritis, class IV - diffuse glomerulonephritis, class V - diffuse membranous glomerulonephritis, and class VI - advanced sclerosing glomerulonephritis (The World Health Organization classification 1982).Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Immunoglobulin Variable Region: That region of the immunoglobulin molecule that varies in its amino acid sequence and composition, and comprises the binding site for a specific antigen. It is located at the N-terminus of the Fab fragment of the immunoglobulin. It includes hypervariable regions (COMPLEMENTARITY DETERMINING REGIONS) and framework regions.Immunoglobulin Idiotypes: Unique genetically-controlled determinants present on ANTIBODIES whose specificity is limited to a single group of proteins (e.g., another antibody molecule or an individual myeloma protein). The idiotype appears to represent the antigenicity of the antigen-binding site of the antibody and to be genetically codetermined with it. The idiotypic determinants have been precisely located to the IMMUNOGLOBULIN VARIABLE REGION of both immunoglobin polypeptide chains.Polysaccharides, Bacterial: Polysaccharides found in bacteria and in capsules thereof.Monocytes: Large, phagocytic mononuclear leukocytes produced in the vertebrate BONE MARROW and released into the BLOOD; contain a large, oval or somewhat indented nucleus surrounded by voluminous cytoplasm and numerous organelles.Lipopolysaccharides: Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
... inflammatory markers and special tests including (ASLO, ANCA, Anti-GBM, Complement levels, Antinuclear antibodies Biopsy of the ... The C3 Nephritic Factor autoantibody stabilizes C3-convertase, which may lead to an excessive activation of complement. Rapidly ... Circulating immune complexes may activate the complement system, leading to inflammation and an influx of inflammatory cells. ... About two-thirds are associated with auto-antibodies to phospholipase A2 receptor, but other associations include cancers of ...
When a BCR binds an antigen tagged with a fragment of the C3 complement protein, CD21 binds the C3 fragment, co-ligates with ... Plasma cell - A long-lived, non-proliferating antibody-secreting cell arising from B cell differentiation. There is evidence ... Antigens that activate B cells with the help of T-cell are known as T cell-dependent (TD) antigens and include foreign proteins ... B-2 cell - FO B cells and MZ B cells. Regulatory B (Breg) cell - An immunosuppressive B cell type that stops the expansion of ...
"Addition of a mu-tailpiece to IgG results in polymeric antibodies with enhanced effector functions including complement- ... For example, the IgM antibodies that bind to the red blood cell A and B antigens might be formed in early life as a result of ... That is, IgM-mediated enhancement does not occur in animals that have been depleted for complement component C3, nor in mutant ... "How antibodies use complement to regulate antibody responses". Mol. Immunol. 61: 79-88. CS1 maint: Multiple names: authors list ...
"Antibodies to native DNA and serum complement (C3) levels. Application to diagnosis and classification of systemic lupus ... Impaired clearance of dying cells is a potential pathway for the development of this systemic autoimmune disease. This includes ... Subtypes of antinuclear antibodies include anti-Smith and anti-double stranded DNA (dsDNA) antibodies (which are linked to SLE ... The body's sensitized B-lymphocyte cells will now produce antibodies against these nuclear-related proteins. These antibodies ...
The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells ... Over 30 proteins and protein fragments make up the complement system, including serum proteins, and cell membrane receptors. ... In contrast, when the internal thioester of C3 reacts with a hydroxyl or amino group of a molecule on the surface of a cell or ... Polymorphisms of complement component 3, complement factor B, and complement factor I, as well as deletion of complement factor ...
The latter is further divided into humoral (or antibody) and cell-mediated components. The humoral (antibody) response is ... This includes regulating factors such as IL-2, IL-10, GM-CSF B, IFN-α. The specificity of the bond between antibody and antigen ... For example, the mean level of C3 in a newborn is approximately 65% of that found in the adult. Phagocytic activity is also ... In neonates, opsonic activity and the ability to activate the complement cascade is very limited. ...
Henoch-Schönlein purpura (HSP) is a systemic disorder caused by deposits of IgA and complement component 3 (C3) in the small ... Ligation of FcαRI by IgA containing immune complexes causes antibody-dependent cell-mediated cytotoxicity (ADCC), degranulation ... "Persistence of Autoreactive IgA-Secreting B Cells Despite Multiple Immunosuppressive Medications Including Rituximab". JAMA ... Production of sIgA against specific antigens depends on sampling of M cells and underlying dendritic cells, T cell activation, ...
"Optimal germinal center B cell activation and T-dependent antibody responses require expression of the mouse complement ... 1976) found complete overlapping of EBV receptors and C3 receptors on human B cells. The canonical Cr2/CD21 gene of subprimate ... "The CD19/CD21 signal transducing complex of human B lymphocytes includes the target of antiproliferative antibody-1 and Leu-13 ... B cells have CR2 receptors on their surfaces, allowing the complement system to play a role in B-cell activation and maturation ...
The antigen-antibody complex can also activate complement through the classical complement pathway. Phagocytic cells do not ... including C3b and C4b which are both parts of C3-convertase. C1q, a member of the C1 complex, is able to interact with the Fc ... activate complement proteins, and target cells for destruction through the action of natural killer (NK) cells. All cell ... Opsonin molecules include: Antibodies are part of the adaptive immune response and are generated by B cells in response to ...
... including lymphocytes (T-cells and B-cells) and antigen presenting cells. These cells coordinate an immune response upon the ... "Antibodies to native DNA and serum complement (C3) levels. Application to diagnosis and classification of systemic lupus ... anti-Sm antibodies, anti-nRNP antibodies, anti-Scl-70 antibodies, anti-dsDNA antibodies, anti-histone antibodies, antibodies to ... If antibodies are present then they will bind to the antigens on the cells; in the case of ANAs, the antibodies will bind to ...
... and immunofluorescence demonstrates IgA and C3 (a protein of the complement system) in the blood vessel wall. However, overall ... These antibodies are of the subclass IgA1 in polymers; it is uncertain whether the main cause is overproduction (in the ... The main findings on kidney biopsy are increased cells and Ig deposition in the mesangium (part of the glomerulus, where blood ... Other regimens include steroids/azathioprine, and steroids/cyclophosphamide (with or without heparin and warfarin). Intravenous ...
... including ASLO, ANCA, Anti-GBM, Complement levels, Anti-nuclear antibodies) ... The C3 Nephritic Factor autoantibody stabilizes C3-convertase, which may lead to an excessive activation of complement.[4]:553 ... Circulating immune complexes may activate the complement system, leading to inflammation and an influx of inflammatory cells.[4 ... About two-thirds are associated with auto-antibodies to phospholipase A2 receptor, but other associations include cancers of ...
The complement system is a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells ... Over 30 proteins and protein fragments make up the complement system, including serum proteins, and cell membrane receptors. ... Once the alternative C3 convertase enzyme is formed on a pathogen or cell surface, it may bind covalently another C3b, to form ... which causes osmotic lysis of the target cell. Kupffer cells and other macrophage cell types help clear complement-coated ...
... complement C3 and magnetite nanoparticles for use in a number of molecular recognition applications. Many different tags and ... that are typically observed with antibodies, may be avoided. These synthetic antibodies were engineered to be stable, non-toxic ... Affimer proteins were developed initially at the MRC Cancer Cell Unit in Cambridge then across two laboratories at the ... Affimer binders have been produced to a large number of targets including ubiquitin chains, immunoglobulins, C-reactive protein ...
... protects host cells from complement-mediated damage by regulating the activation of C3 convertases on host cell surfaces; ... "Optimal Germinal Center B Cell Activation and T-Dependent Antibody Responses Require Expression of the Mouse Complement ... The gene including the repeats is highly conserved in primates possibly because of the ability of the repeats to bind ... appears to be critical for generation of appropriately activated B cells of the germinal centre and for mature antibody ...
... complement C3, and thrombomodulin). This results in platelet activation, damage to endothelial cells (cells that line the blood ... a monoclonal antibody that is a first-in-class terminal complement inhibitor, management options for patients with aHUS were ... Clinical signs and symptoms of complement-mediated TMA can include abdominal pain, confusion, fatigue, edema (swelling), nausea ... indicative of the breakdown of red blood cells), anemia (low red blood cell count)/schistocytes (damaged red blood cells), ...
Beta-2 comprises C3 (Complement protein 3). It is raised in the acute phase response. Depression of C3 occurs in autoimmune ... Therapeutic monoclonal antibodies monoclonal antibodies (mAb), also migrate in this region and may be misinterpreted as a ... Lysozyme may be seen as a band cathodal to gamma in myelomonocytic leukaemia in which it is released from tumour cells. Jenkins ... Of note, any protein migrating in the gamma region will be stained and appear on the gel, which may include protein ...
... the donor's red blood cells are destroyed by recipient's preformed antibodies through the activation of complement system. Thus ... Properdin then binds to complement C3 in the donor blood, facilitating the reaction through the alternate pathway cascade. The ... Prophylactic measures to reduce the risk of renal failure may include low-dose dopamine, vigorous hydration with intravenous ... Macrophages then recognise these IgG antibodies and engulf these red blood cells, removing the red blood cells from the blood ...
The absence of C3 has also been shown to decrease IL-2 receptor expression on T cells. Levels of complement are regulated by ... C3 convertase activity is also regulated without C3b inactivation, through complement control proteins, including decay- ... recognizes the Fc region of IgM or IgG antibodies bound to a pathogen. C1q mediates the classical pathway by activating the C1 ... C3a is an effector of the complement system with a range of functions including T cell activation and survival, angiogenesis ...
... which depletes C3), soluble complement receptor type 1, anti-C5 antibodies, or C1 inhibitor (C1-INH). Disadvantages of this ... Most of these antibodies are the IgM class, but also include IgG, and IgA. The epitope XNAs target is an α-linked galactose ... stimulated by CD4+ T cells) and NK cells (stimulated by the release of Il-2). Thus, the role of MHC molecules and T cell ... The binding of XNAs initiate complement activation through the classical complement pathway. Complement activation causes a ...
The immune complex serves as an activator that triggers a response from the C5b - C9 complements, which form a membrane attack ... The immune complexes are formed by binding of antibodies to antigens in the glomerular basement membrane. The antigens may be ... This, in turn, stimulates release of proteases and oxidants by the mesangial and epithelial cells, damaging the capillary walls ... Within membranous glomerulonephritis, especially in cases caused by viral hepatitis, serum C3 levels are low. The defining ...
One study has identified antibodies to an M-type phospholipase A2 receptor in 70% (26 of 37) cases evaluated.[2] In 2014, a ... The immune complex serves as an activator that triggers a response from the C5b - C9 complements, which form a membrane attack ... This, in turn, stimulates release of proteases and oxidants by the mesangial and epithelial cells, damaging the capillary walls ... Within membranous glomerulonephritis, especially in cases caused by viral hepatitis, serum C3 levels are low.[7] ...
Here, it is released by mast cells and causes activation of complement and kinins. This group includes the calpains. Basic ... Proteases determine the lifetime of other proteins playing important physiological role like hormones, antibodies, or other ... the S1 and C3 families within the PA clan). Each family may contain many hundreds of related proteases (e.g. trypsin, elastase ... Natural protease inhibitors include the family of lipocalin proteins, which play a role in cell regulation and differentiation ...
... which depletes C3), soluble complement receptor type 1, anti-C5 antibodies, or C1 inhibitor (C1-INH). Disadvantages of this ... T cells. Antigens of phagocytosed graft cells can also be presented by the host's class I MHC molecules to CD8+ T cells.[1][29] ... Most of these antibodies are the IgM class, but also include IgG, and IgA.[21] ... The binding of XNAs initiate complement activation through the classical complement pathway. Complement activation causes a ...
C3,C5-C9) are more susceptible to N. meningitidis infection than complement-satisfactory persons,[27][28][29][30][31][32][33] ... Infected fluid from the meninges then passes into the spinal cord, causing symptoms including stiff neck, fever and rashes. The ... Andreoni J, Käyhty H, Densen P (July 1993). "Vaccination and the role of capsular polysaccharide antibody in prevention of ... Vaccination against meningitis does not decrease CD4+ T-cell counts or increase viral load in HIV-infected individuals, and ...
... cell responses to mitogens and allogeneic cells, cytokine production by cells Tests for B cell function: antibodies to routine ... The basic tests performed when an immunodeficiency is suspected should include a full blood count (including accurate ... Complement deficiencies are the result of a lack of any of these proteins. They may predispose to infections but also to ... C3 deficiency (recurrent pyogenic infections) C5 deficiency (Neisserial infections, SLE) C6 deficiency (idem) C7 deficiency ( ...
... anti-dsDNA antibodies by ELISA; 2) complement proteins C3/C4 by nephelometry (mg/dL); 3) Percentage of CD4+ T helper cell ... including Tumor Necrosis Factor (TNF) alpha, Transforming Growth Factor (TGF) Beta1, Interleukin (lL) 6, IL-17A, IL-10, B-cell ... Active Urinary Sediment (, 5 red blood cells/high-power field and/or ,8 white blood cells/high-power field and/or cylindruria ... Mesenchymal Stromal Cells (MSC´s) in Renal Lupus (MSC-ROLE). The safety and scientific validity of this study is the ...
What is Complement C3 and Complement C4? Meaning of Complement C3 and Complement C4 medical term. What does Complement C3 and ... Looking for online definition of Complement C3 and Complement C4 in the Medical Dictionary? Complement C3 and Complement C4 ... Related tests include anticardiolipin antibody, ANA, complement total, cryoglobulin, and ESR. * Refer to the Immune System ... of the complement system, but cells in other tissues can also produce C3. C3 is an essential activating protein in the classic ...
C3), and toll-like receptor-1 (TLR-1). Anti-Ich antibodies were detected in fish received pcDNA3.1-IAg52a, pcDNA3.1-IAg52b and ... Suggested studies include improved transfection efficiency, use of appropriate adjuvants and including additional parasite ... antibody IgM), cluster of differentiation 4 (CD4), major histocompatibility complex I (MHC I), and T cell receptor a (TcR-a) ... Fish vaccinated with DNA vaccines or theronts showed increased gene expression of the cytokine interferon (IFN-y), complement ...
Clearance from the circulation was independent of natural antibodies or complement factor C3, and instead relied on scavenger ... advanced  Advanced search can include the following:. • OR operator: , • NOT operators: - OR !. • phrase search: "breast ... eg.(cancer,cancers)(cervical,cervix)!("Squamous cell carcinoma",SCC). will return records where either the words cancer or ... AbstractAlphaviruses, including Chikungunya (CHIKV) and Venezuelan equine encephalitis virus (VEEV), are among the leading ...
Molecular screening for autoimmune thyroiditis including immunoglobulin receptors on B-cells, T-cell receptors, and major ... complement levels (C1, C1a, C1 esterase inhibitor, C3, C4, C5-C9); LE-prep testing; lupus anticoagulant (dilute Russells viper ... and anti-leukocyte antibody tests (direct and indirect anti-neutrophil cytoplasmic antibody, antilymphocyte antibody, etc.). ... The data includes obtaining data related to at least one of the value of the methyl malonic acid, the fucose-containing cell ...
Molecular screening for autoimmune thyroiditis including immunoglobulin receptors on B-cells, T-cell receptors, and major ... complement levels (C1, C1a, C1 esterase inhibitor, C3, C4, C5-C9); LE-prep testing; lupus anticoagulant (dilute Russells viper ... and anti-leukocyte antibody tests (direct and indirect anti-neutrophil cytoplasmic antibody, antilymphocyte antibody, etc.). ... The data includes obtaining data related to at least one of the value of the methyl malonic acid, the fucose-containing cell ...
Monocyte subsets were sorted and co-cultured with CD4+ T cells and CD19+ B cells. Then, T and B cells were collected for ... Monocyte subsets were sorted and co-cultured with CD4+ T cells and CD19+ B cells. Then, T and B cells were collected for ... Also, CD16+ monocytes had enhanced impacts on CD19+ B cells to differentiate into plasma B cells and regulatory B cells with ... Also, CD16+ monocytes had enhanced impacts on CD19+ B cells to differentiate into plasma B cells and regulatory B cells with ...
We show that several types of immune cells infiltrate the adipose tissue and these include macrophages, neutrophils, NK cells, ... B1 and B2 cells. Our main focus is how the adipose tissue affects immune responses, in particular B cell responses and antibody ... NK cells, innate lymphoid cells (ILCs), eosinophils, T cells, B1 and B2 cells. Our main focus is how the adipose tissue affects ... in particular B cell responses and antibody production. The role of leptin in generating inflammation and decreased B cell ...
... including promoting phagocytosis of pathogens by acting as an opsonin, inducing lysis of bacteria or susceptible cells and ... Activation of the alternative pathway begins with the C3 molecule. C3 is the central protein of all three complement pathways ... The alternative and lectin pathways are evolutionarily older than the classical pathway and do not require antibody for ... CD59 on hematologic cells is required to prevent unregulated complement lysis. This protein is bound to cells by a ...
Complete blood cell count values were within normal range with negative direct Coombs tests, as was complement including its C3 ... Antinuclear antibodies were positive (1:640) but anti-Sm antibodies were negative, as were anti-ENA antibodies. The aPLAbs ... a monoclonal antibody that blocks the binding of circulating B-cell activating factor to its target receptors on B cells.8 ... Regulatory T cells and B cells: implication on autoimmune diseases. Review. Int J Clin Exp Pathol. 2013;6(12):2668-2674. ...
Recent studies, including our own, have indicated that astrocytes are highly phagocytic cells ... ... Ben Barres on NFκB-activated astroglial release of complement C3 compromises neuronal morphology and function associated with ... Ben Barres on Brain Shuttle Ferries Antibodies Across the Blood-Brain Barrier. COMMENT Niewoehner and colleagues set out to ... Ben Barres on How Cells, and Drugs, Try to Control Glutamate in the Synapse. COMMENT Overall, the data now show that loss of ...
... low complement C3). *Positive antinuclear antibody (ANA) test result at time of study entry ... Active infection, including HIV, hepatitis B or C. *History of cancer, except carcinoma in situ and treated basal and squamous ... Participants were categorized as having hypocomplementemia if their serum complement test results (C3, and C4) were below the ... C3, C4), frequency of flares, patient global assessment (PGA), SF36 total scores, and BILAG-2004 scores. ...
CNS vasculitis must be distinguished from noninflammatory vasculopathies, including dissection, Moyamoya, sickle cell disease, ... C3 complement), (2) hematologic tests (hemoglobin, platelets, white blood count), (3) prothrombotic testing according to ... antinuclear antibody [ANA], antineutrophil cytoplasmic antibodies [ANCA], anticardiolipin antibodies [ACLA]), and (5) ... Exclusion criteria included (1) neonates, (2) significant underlying conditions or defined cause of CNS vasculopathy, including ...
... persons with persistent complement component diseases, including inherited or chronic deficiencies in C3, C5-C9, properdin, ... including measles neutralizing antibody titers, measles-specific T-cell proliferation, and cytokine profiles.Measles ... 370 cells/microliter; P < or = 0.003), and that there is a reciprocal increase in memory cells, such that the total CD8 T cell ... 200 cells per microliter), or to CD4⁺ count 550 cells per microliter at delivery. CD4 550 cells per microliter at delivery. ...
... induction of anti-neutrophil cytoplasmic antibody (ANCA), to the hosts. Since ANCA can induce NET formation in the primed ... Other ANCAs, including PR3-ANCA, and anti-DNA antibody were negative even at this time. Complement values were as follows: C3 ... The white blood cell count was 8700/μl with 2.0% eosinophils, red blood cell count was 307 × 104/μl, and platelet count was ... Anti-DNA antibody was negative. Complement values were as follows: C3 162.2 mg/dl (normal range, 71-135 mg/dl) and C4 37.7 mg/ ...
Immune complexes promote an inflammatory response by activating complement and attracting inflammatory cells, including ... Antibodies to double-stranded DNA (dsDNA). * Complement (C3, C4, and CH50) ... FcγR genes include the following:. * These mediate the binding of IgG and IgG-containing immune complexes to cells such as ... Complement genes include the following:. * C1Q, C1R, and C1S deficiencies are associated with SLE, lupus nephritis, and ...
... complement components 3 and 4 (C3 and C4) levels, human antihuman antibody (HAHA) levels, B-cell (CD20+) and T-cell (CD3+) ... Major targets of these agents include B cells, T cells and cytokines.5 To date, however, success has been limited by the ... High doses of epratuzumab may affect a specific function of B cells, a particular subset of B cells, the trafficking of B cells ... Changes from baseline in B-cell and CD22 levels. (A) Changes in absolute B-cell counts (cells/µl) (B) Changes in mean ...
C3 decreased. C4 decreased. Rheumatoid factor negative. Anti-nuclear antibodies Titer of 1:80. Creatinine 1.8 mg/dL. Urinalysis ... Serum C3 and C4 complement levels were normal. Bronchoscopy revealed no obstructing lesions or bloody secretions. An open lung ... Common findings include eosinophilia, pulmonary infiltrates, skin rash (including LCV, and occasionally a characteristic ... Giant cell arteritis. * A 68-year-old man with a history of diffuse atherosclerotic vascular disease presents with purplish ...
... anti-ribonucleoprotein and antineutrophil cytoplasmic antibodies, were negative. Serum C3 and C4 complement factors were low, ... a speckled pattern and a double-stranded DNA antibody titer of 1:20 positive. The rest of the autoantibody profiles, including ... G level of 0.28 g/L with a normal number of cells (white cell count was zero). Electromyography revealed a severe demyelinating ... The results of the blood cell count and hepatic function tests were normal. The levels of serum creatinine, and urea nitrogen ...
... including both alloantibodies and autoantibodies) that can fix complement, however, activate complement up to the C3 stage but ... Although antibody-coated red cells can also be destroyed extravascularly without complement activation, red cell removal is ... complement-binding antibody and large numbers of closely situated red cell antigens, complement activation can proceed to ... Activation of complement cascade via the antibody-mediated classical pathway can initiate red blood cell (RBC) destruction, ...
... inducible T-cell costimulator (ICOS), and programmed death 1 (PD-1) of positive TFH cells by flow cytometry. The level of sera ... This study is aimed at examining the frequencies of different subsets of CD4,sup,+,/sup,CXCR5,sup,+,/sup, TFH cells in adult ... Also, the percentages of CD4,sup,+,/sup,CXCR5,sup,+,/sup,ICOS,sup,+,/sup, TFH cells were correlated positively with the levels ... The potential correlation between the frequency of different subsets of TFH cells and the values of clinical measures in MCD ...
Complement mediates the response in the later stages of acute inflammation. When activated, complement alters cell membranes, ... Cell Mediators Cell mediators include histamine, serotonin (5-hydroxytryptamine (5-HT)), prostaglandins (PGs), platelet- ... Antibody-producing cells in human periapical granulomas and cysts. J Endodon 1981;7:447. 85. Block RM, Lewis RD, Sheats JB, ... The levels of circulating immune complexes and C3 complement in patients with chronic periapical lesions have been found to be ...
... and hepatitis C antibody. Serum complement levels including C3, C4, and CH50 were within normal limits. Urinalysis revealed 4+ ... and microscopic examination showed fewer than five red blood cells per high-power field and no white blood cells or casts. ... with negative anti-double-stranded DNA antibody and negative viral serologies including HIV, hepatitis B surface and core ... The clinical presentation included proteinuria (mean 10.1 g/d; range 1.3 to 26.3 g/d) and renal insufficiency (mean serum ...
... online.The complement system is a complex cascade involving proteolytic cleavage of serum glycoproteins often activated by cell ... This cascade ultimately results in induction of the inflammatory response, phagocyte chemotaxis and opsonization, and cell ... complement C3.. The Classical Pathway:. The classical pathway mediates specific antibody responses. The classical pathway is ... Other deleterious effects of complement activation include, degranulation of neutrophils, basophils and mast cells, unwanted ...
Role of lupus auto-antibodies (antinuclear antibody and dsDNA) and complements (C3/C4) Auto-antibodies in SLE and complements ( ... 5 red blood cells (RBCs)/high-power field) and active urinary sediment (granular casts, white blood cell (WBC) casts, RBC casts ... Treatment options include switching from MMF to CYC or from CYC to MMF; rituximab may be given as add-on treatment or ... low complement C3 (p , 0.0001), low complement C4 (p = 0.009) and positive dsDNA (p = 0.039). [5] Role of renal biopsy The ...
  • Therapeutic monoclonal antibodies (mAbs) have proven successful in the clinic and are now in widespread use for the treatment of a variety of diseases including cancer, autoimmune, and infectious diseases. (frontiersin.org)
  • Our RabMAb ® technology is a patented hybridoma-based technology for making rabbit monoclonal antibodies. (abcam.com)
  • In the context of metalloprotease-mediated transactivation of the epidermal growth factor receptor, different monoclonal antibodies against ADAM17 / TACE were characterized for their ability to block the sheddase. (uni-wuerzburg.de)
  • Of the 8 plasma membrane receptors for complement, only deficiencies of CR3 and CR4 due to CD18 deficiency have been described, known as leukocyte adhesion deficiency (LAD) type 1 . (medscape.com)
  • [ 8 ] Deficiency of CD18 on phagocytic cells causes LAD type 1 (see Table 2). (medscape.com)
  • 300 cells/µL) in the absence of a causal infection or immune deficiency and can manifest with opportunistic infections. (jci.org)
  • Depletion of Treg cells by anti-CD25 monoclonal antibody (mAb) negated the survival advantages conferred by C3 deficiency. (nature.com)
  • Our results indicate for the first time that C3 deficiency can prolong MHC-II molecule mismatched skin allograft survival, which is further confirmed to be associated with increased CD4 + CD25 + Treg cell population expansion and attenuated Th1/Th17 response. (nature.com)
  • It was indicated that intra-renal C3 deficiency (C3 −/− ) prolonged renal allograft survival and caused a defective alloreactive T cell response when compared with C3 positive (C3 +/+ ) allografts 18 . (nature.com)
  • On the contrary, in a minor H disparate skin transplant model, results suggested that C1q or C3 deficiency (C1q −/− or C3 −/− ) accelerated graft rejection as well as impaired intranasal tolerance induction 19 . (nature.com)
  • Here it is proposed that this CD8+ T-cell deficiency underlies the development of chronic autoimmune diseases by impairing CD8+ T-cell control of Epstein-Barr virus (EBV) infection, with the result that EBV-infected autoreactive B cells accumulate in the target organ where they produce pathogenic autoantibodies and provide costimulatory survival signals to autoreactive T cells which would otherwise die in the target organ by activation-induced apoptosis. (hindawi.com)
  • It is also proposed that deprivation of sunlight and vitamin D at higher latitudes facilitates the development of autoimmune diseases by aggravating the CD8+ T-cell deficiency and thereby further impairing control of EBV. (hindawi.com)
  • The present article presents a further development of this hypothesis, proposing that susceptibility to develop chronic autoimmune diseases after EBV infection is dependent on a genetically determined quantitative deficiency of the cytotoxic CD8+ T cells that normally keep EBV infection under tight control. (hindawi.com)
  • Regarding the observations of thrombotic thrombocytopenic purpura patients, in whom a von Willebrand factor protease (ADAMST-13) deficiency may be inherited or acquired secondary to IgG antibodies, it was speculated that HUS might occur in a context of an autoimmune disease with the development of anti-FH antibodies leading to an acquired FH deficiency. (asnjournals.org)
  • The plasma FH activity was found to be decreased, whereas plasma FH antigenic levels and FH gene analysis were normal, indicating that the presence of anti-FH antibodies led to an acquired functional FH deficiency. (asnjournals.org)
  • This report supports for the first time that HUS may occur in a context of an autoimmune disease with the development of anti-FH-specific antibody leading to an acquired FH deficiency. (asnjournals.org)
  • Regarding these observations, we speculate that HUS might occur in a context of an autoimmune disease as described in patients with TTP, in whom a von Willebrand factor protease (ADAMST-13) deficiency may be inherited or acquired secondary to IgG antibodies ( 12 - 16 ). (asnjournals.org)
  • Note the image below, as well as the article Pediatric Complement Receptor Deficiency may be helpful. (medscape.com)
  • Antibody deficiency and common variable immunodeficiencies were the most common categories and phenotypes, respectively. (zuluecco.com)
  • Their PID entities were combined immunodeficiency and specific antibody deficiency, respectively. (zuluecco.com)
  • When biochemical analysis reveals the causal abnormality of the complement deficiency (CD), molecular mechanisms remains frequently undetermined. (frontiersin.org)
  • Here, using direct sequencing analysis of the coding region we report the pathogenic variants spectrum that underlie the total or subtotal complement deficiency in 212 patients. (frontiersin.org)
  • Results from this large genetic investigation provide evidence of a restricted number of molecular mechanisms leading to complement deficiency and describe the clinical potential adverse events of anti-complement therapy. (frontiersin.org)
  • Restricted number of molecular mechanisms leading to complement deficiency. (frontiersin.org)
  • Severe or multiple infections-mainly meningococcal infections-or severe autoimmune diseases (AID) in particular with childhood onset are the main features associated with complement deficiency (CD) ( 6 - 10 ). (frontiersin.org)
  • We propose that this localized deposition of complement fragments aids in the fusion process between the spermatozoa and egg, in a role akin to that of complement in immune adherence. (jci.org)
  • Using a flow-based method, we characterized the presence of anti-lymphocyte Ab in the whole cohort of 72 patients, as well as the Ab functional capability of inducing antibody-dependent cell-mediated cytotoxicity (ADCC), complement deposition, and complement dependent cytotoxicity (CDC). (jci.org)
  • Immunofluorescent staining of biopsy specimens from the lungs and kidneys of patients with Goodpasture syndrome reveals a characteristic linear pattern of antibody deposition at the basement membrane. (rheumaknowledgy.com)
  • A range of other immunosuppressants may be used either concurrently with glucocorticoids or alone for the treatment of various immune-mediated dermatoses, including systemic lupus erythematosus (SLE), pemphigus complex, bullous pemphigoid, and vasculitis. (merckvetmanual.com)
  • Epstein-Barr virus (EBV) has been suspected of involvement in the pathogenesis of various chronic autoimmune diseases since the finding of elevated levels of antibody to the virus in systemic lupus erythematosus (SLE) in 1971 [ 1 ]. (hindawi.com)
  • Applications Reported: This eBio22D1 (22D1) antibody has been reported for use in flow cytometric analysis, immunoprecipitation, immunohistology staining of frozen tissue sections, and ELISA. (thermofisher.com)
  • As zonulin concentrations did not correlate to the haptoglobin genotypes, we investigated the specificity of the zonulin ELISA assay using antibody capture experiments, mass spectrometry, and Western blot analysis. (frontiersin.org)
  • Combining mass spectrometry and Western blot analysis using the polyclonal antibodies used in the ELISA kit, we identified properdin as another member of the zonulin family. (frontiersin.org)
  • 12 Receptor (TNFRSF)-Interacting serine-threonine Kinase 1 (RIPK1) ELISA Kits from 8 manufacturers are available on www.antibodies-online.com. (antibodies-online.com)
  • Considerable clinical and experimental data now suggests these antibodies are pathogenic. (asnjournals.org)
  • Patients with immunologically active disease can now be separated from those with inactive disease and therapeutic initiatives in active disease can be adjusted to the presence and levels of the pathogenic antibody causing the disease rather than relying empirically on clinical consequences of immune injury to the glomerulus such as proteinuria or reduced GFR ( 1 , 4 - 7 ). (asnjournals.org)
  • The pathogenic mechanisms leading to FSGS share a common cellular target, the podocyte, a terminally differentiated cell whose foot processes act as structural parts of the glomerular filtration barrier. (frontiersin.org)
  • FSGS is now considered as part of the podocytopathy spectrum of diseases, a term that includes all entities in which the podocyte is the primary target of the underlying pathogenic process ( 3 ). (frontiersin.org)
  • The report provided includes Candida albicans (a microscopic fungal organism and pathogenic yeast). (rnlabs.com.au)
  • They bind glycoprotein or glycolipid moieties on urothelial cells allowing the bacteria to attach to the epithelium and persist within the urinary tract. (bmj.com)
  • Electron microscopy and biochemical studies have suggested that these bacterial cell wall projections bind to the urothelial mannosylated glycoproteins uroplakin Ia and Ib via the adhesin subunit FimH, located at the fimbrial tip. (bmj.com)
  • C3b and C4b bind to CR1, which is present on various phagocytes and also on erythrocytes and B cells. (medscape.com)
  • ANA are antibodies produced by the immune system that bind. (adam.com)
  • Opsonized immune complexes (coated by C3b and C4b) bind to CR1, mostly on red blood cells, and are cleared through the liver where they can be transferred to CR3-bearing phagocytes and endocytosed. (medscape.com)
  • The saliva composition of the tick and other hematophagous arthropods is complex and includes vasodilators, anti-coagulation compounds, and platelet aggregation inhibitors ( 2 , 4 ). (frontiersin.org)
  • Investigating platelet-complement interactions Platelets interact with the AP regulator Factor H (CFH), which is also synthesized by megakaryocytes and can be taken up by platelets in vivo and in vitro. (sickkids.ca)
  • The clinical manifestations of IgG4-RD are usually tumor-like masses or organ enlargement, which result from dense tissue infiltration by immune cells and expansion of the extra-cellular matrix. (merckmanuals.com)
  • The common clinical manifestations include esophageal varices, splenomegaly, and hypersplenism. (storysteel.ml)
  • Understanding of the fundamental processes underlying the versatile clinical manifestations of COVID-19 is incomplete without comprehension of how different immune cells are recruited to various compartments of virus-infected lungs, and how this recruitment differs among individuals with different levels of disease severity. (nature.com)
  • Clinical features include lack of attached gingiva already present in childhood, easy bruising, pretibial haemosiderotic plaques, doughy skin, hoarse voice, poor wound healing, and hypermobility of joints. (frontiersin.org)
  • My research has translational character and includes both clinical and basic research: I have established an international registry with biorepository (www.kidcom.ca). (sickkids.ca)
  • It can be delayed or even absent in some clinical forms where there is a simultaneous destruction of red blood cells and erythroblasts, marrow while being the seat of ineffective erythropoiesis. (medical-actu.com)
  • Which of the following immunotherapy approaches has demonstrated great potential in early clinical trials in patients with B-cell leukemia? (msdmanuals.com)
  • antibodies in clinical seropositive dogs bound to 4-25 igm and up to 40 or more igg antigenic determinants. (liverpool.ac.uk)
  • There is indeed upon exposure to cold extremities vascular events: Raynaud's syndrome, acrocyanosis caused by the agglutination of red blood cells in the subcutaneous tissue of the nose, toes, ears, sudden discoloration skin accompanied by numbness and sometimes pain. (medical-actu.com)
  • COVID-19 can affect any organ, including the vascular system. (fortunejournals.com)
  • Mice deficient in both CD21 and CD35 exhibit normal B cell development but severely compromised germinal center development, antibody production, and establishment of protective microbial immunity. (rndsystems.com)
  • Herein, we investigate the role of complement component 3 (C3) in a single MHC-II molecule mismatched murine model of allograft rejection using C3 deficient mice (C3 −/− ) as skin graft donors or recipients. (nature.com)
  • In the CASPR2-IgG injected mice, there was also increased microglia density, morphological changes in both microglia and astrocytes and raised complement C3 expression on astrocytes, all consistent with glial activation. (ox.ac.uk)
  • Although the behavioural changes in mice were limited to social interactions and mild working-memory defects, the neuropathological features indicate potentially widespread effects of the antibodies on different brain regions. (ox.ac.uk)
  • When these mice were 16 months old, they displayed abnormal microglia with enlarged cell bodies and shorter, thicker and fewer processes. (aging-us.com)
  • The virulence factors most commonly associated with these organisms include possession of fimbriae with adhesin tips, protectins, bacterial capsule including lipopolysaccharide (LPS), and production of toxins such as haemolysin and colony necrotising factor. (bmj.com)
  • A major contribution relates to the investigating of complement and von Willebrand Factor (VWF) identifying VWF as new complement regulator on ECs. (sickkids.ca)
  • Synthetic peptide within Human Complement factor B aa 750-850 (C terminal). (abcam.com)
  • Since these mutations are distributed over the whole Fc sequence, binding to other Fc effectors, such as complement C1q and FcγRs, was dramatically modified, even by mutations distant from these effectors' binding sites. (frontiersin.org)
  • Heterozygous missense or in-frame insertion/deletion mutations in complement 1 subunits C1r and C1s cause periodontal Ehlers-Danlos Syndrome (pEDS), a specific EDS subtype characterized by early severe periodontal destruction and connective tissue abnormalities like easy bruising, pretibial haemosiderotic plaques, and joint hypermobility. (frontiersin.org)
  • A similar phenomenon is observed with C3 mutations found in aHUS. (aurignacien.com)
  • The mutations affected two domains of FN (Hep-II domain for the W1925R and the L1974R, and Hep-III domain for the Y973C) that play key roles in FN-cell interaction and in FN fibrillogenesis. (pnas.org)
  • Tick saliva, as in other hematophagous arthropods, contains pharmacological and immunological active compounds, which modulate local and systemic immune responses and induce antibody production. (frontiersin.org)
  • Moreover, C3 −/− allografts caused attenuated Th1/Th17 responses, but increased CD4 + CD25 + Foxp3 + regulatory T (Treg) cell expression markedly in local intragraft and H-2 bm12 recipients. (nature.com)
  • Furthermore, biological responses induced by LPA or S1P such as migration in breast cancer and HNSCC cells, depend on ADAM17 and proHB-EGF/proAR function, respectively, suggesting that highly abundant GPCR ligands may play a role in tumour development and progression. (uni-wuerzburg.de)
  • There is an increasing recognition that inflammation plays a critical role in neurodegenerative diseases of the CNS, including Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and the prototypic neuroinflammatory disease multiple sclerosis (MS). Differential immune responses involving the adaptive versus the innate immune system are observed at various stages of neurodegenerative diseases, and may not only drive disease processes but could serve as therapeutic targets. (jci.org)
  • Increasing appreciation for the role of inflammation in neurodegenerative diseases of the CNS, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and the prototypic neuroinflammatory disease multiple sclerosis (MS), has identified differential immune responses involving the adaptive versus the innate immune systems at various stages of disease. (jci.org)