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Antibodies are synthesized by the plasma cells formed when antigen-specific groups (clones) of B lymphocytes respond to the presence of antigen. The developmental process of antibody production begins when stem cells are transformed into B lymphocytes; this transformation usually is completed a few months after birth, at which time the lymphocytes migrate to lymphoid tissue primarily located in the lymph nodes, although they are also found in the spleen, gastrointestinal tract, and bone marrow.
Antibody production, its interaction with a specific antigen, and the activation of complement (C), an interrelated group of eleven proteins, are the major components of the humoral system of immunity. Fortunately, the immune response of antibody and complement can be transferred passively from one individual to another, as for example the transfer of maternal antibody across the placental barrier to the fetus, who has not yet developed a mature immune system. An antibody present in an individual without known prior exposure to the corresponding red cell antigen is termed an isoagglutinin. (Examples are the ABO antibodies anti-A, anti-B, and anti-A,B.)
Antibodies can be classified according to their mode of action as they react to and set about defending the body against foreign invaders. Some cause clumping together of bacterial cells (agglutination) and are called agglutinins. Those antibodies that cause bacterial cells to dissolve or liquefy are called bacteriolysins. This activity is assisted by complement, which interacts with the antigen-antibody complex in such a way that the cell ruptures and there is dissolution (lysis) of the cell body. Opsonins coat the outside of bacteria, making them more attractive to phagocytes. Other types of antibodies include those that neutralize the toxins of antigens (antitoxins) and those that cause precipitation of antigens in a fluid medium (precipitins).
an·ti·bod·y (Ab),(an'tē-bod'ē), Avoid the jargonistic use of the plural antibodies when the reference is to a single antibody species.
See also: immunoglobulin.
antibodyAn immunoglobulin produced by plasma cells, which has a specific amino acid sequence and specifically binds to the antigen(s) (e.g., foreign proteins, microbes or toxins) that induced its synthesis; antibodies may also bind to closely related antigens.
antibodyImmunology An immunoglobulin produced by plasma cells, which has a specific amino acid sequence and specifically binds to the antigen(s)–eg, foreign proteins, microbes or toxins, that induced its synthesis; antibodies may bind to closely related antigens. See Acetylcholine receptor antibody, Anticardiolipin antibody, Anticentromere antibody, Anti-double-stranded DNA antibody, Anti-epidermal antibody, Anti-extractable nuclear antibody, Antigliadin antibody, Antihistone antibody, Anti-idiotype antibody, Anti-insulin antibody, Anti-islet cell antibody, Anti-Jo-1 antibody, Anti-LANA antibody, Antimicrosomal antibody, Antimitochondrial antibody, Antimyelin antibody, Antimyeloperoxidase antibody, Antineuronal-nuclear antibody, Antineutrophil cytoplasmic antibody, Antinuclear antibody, Antiparietal cell antibody, Anti-platelet antibody, Anti-PRP antibody, Anti-Purkinje cell antibody, Anti-receptor antibody, Anti-reticulin antibody, Anti-ribosomal antibody, Anti-Ro/SSA antibody, Anti-single-stranded DNA antibody, Anti-striated muscle antibody, Anti-thyroglobulin antibody, Antithyroid antibody, Antithyroid peroxidase antibody, Anti-tumor necrosis factor- α monoclonal antibody, Autoantibody, Bexxar radiolabeled monoclonal antibody, Secondary antibody, Binding antibody, Blocking antibody, Catabolic antibody, Catalytic antibody, Chimeric antibody, Core antibody, Cross-reactive antibody, Designer antibody, Enhancing antibody, Fluorescent treponemal antibody, Functional antibody, GAD antibody, Glutamic acid decarboxylase autoantibody, HAMA antibody, Heterophile antibody, HIV antibody, HTLA antibody, Humanized antibody, Immunoglobulin, Insulin receptor antibody, Intrinsic factor antibody, Islet antibody, Isotypic control antibody, Ku antibody, LW antibody, Miniantibody, MOC-31 antibody, Monoclonal antibody, Neutralizing antibody, Parietal cell antibody, Plantibody antibody, PM-1 antibody, Polyclonal antibody, Primary antibody, Purkinje cell antibody, RANA antibody, Scleroderma antibody, Sjögren antibody, Sm antibody, Smooth muscle antibody, Sperm antibody, Thyroid stimulating hormone receptor antibody, Trichinosis antibody, Warm antibody.
See also: immunoglobulin
antibody(ant'i-bod?e) [ anti- + body],
Antibodies neutralize or destroy antigens in several ways. They can initiate lysis of the antigen by activating the complement system; neutralize toxins released by bacteria, coating (opsonizing) the antigen or forming a complex to stimulate phagocytosis; promote antigen clumping (agglutination); or prevent the antigen from adhering to host cells.
An antibody molecule consists of four polypeptide chains (two light and two heavy), which are joined by disulfide bonds. The heavy chains form the complement-binding site, and the light and heavy chains form the site that binds the antigen.
acetylcholine receptor binding antibodyAbbreviation: AChR-Ab
anticardiolipin antibodyAbbreviation: aCLa
anticyclic citrullinated peptide antibodyAbbreviation: anti-CCP
anti–DNase B antibody
antiendothelial cell antibody
antineuronal nuclear antibodyAbbreviation: ANNA
antineutrophil cytoplasmic antibodyAbbreviation: ANCA
antinuclear antibodyAbbreviation: ANA
antiphospholipid antibodyAbbreviation: aPLa
anti–proliferating cell nuclear antigen (PCNA) antibodyAbbreviation: anti-PCNA
antiribosomal P antibody
anti-scl-70 antibodyAnti-topoisomerase I antibody.
antithyroperoxidase antibodyAbbreviation: TPOAb
anti-topoisomerase I antibody
diffusely cytoplasmic anti-neutrophil cytoplasmic antibodyAbbreviation: C-ANCA.
direct fluorescein-conjugated antibodyAbbreviation: DFA
Direct fluorescent antibody.
direct fluorescent antibodyAbbreviation: DFA
Donath-Landsteiner antibodySee: Donath-Landsteiner antibody
fluorescent antibodyAbbreviation: FA
glutamic acid decarboxylase antibodyAbbreviation: GADA
monoclonal antibodyAbbreviation: MoAB
Hybridoma cells, used to produce monoclonal antibodies, are formed by the fusion of a spleen cell from a mouse immunized with an antigen and a multiple myeloma cell (a cancerous plasma B cell). The fused cells are screened to identify those that secrete antibodies against a specific antigen. A continuous supply of these antigen-specific monoclonal antibody secreting cells can then be grown in cultures.See: antibody; B cell; hybridoma
panel reactive antibodyAbbreviation: PRA
perinuclear antineutrophil cytoplasmic antibodyAntimyeloperoxidase antibody.
p504s antibodyAlpha-methylacyl-CoA racemase.
radionuclide-linked monoclonal antibody
toxin-linked monoclonal antibody
warm antibodyWarm autoagglutinin.illustration
antibodyA Y-shaped protein molecule, called an IMMUNOGLOBULIN, produced by the B group of lymphocytes in response to the presence of a ANTIGEN. An appropriate B lymphocyte is selected from the existing repertoire. This then produces a clone of PLASMA CELLS each capable of synthesizing large numbers of specific antibodies to combat the infection. The B cells also produce memory cells. Subsequent infection with the same antigen prompts the memory cells to clone plasma cells and produce the correct antibodies without further delay. This is an important way in which an infection leads to subsequent immunity. Antibodies are able to neutralize antigens or render them susceptible to destruction by PHAGOCYTES in the body. The basic structure of an antibody consists of four polypeptide chains linked by disulphide bridges, two larger structures called HEAVY CHAINS and two smaller called LIGHT CHAINS.
antibody (Ab)a type of protein called an IMMUNOGLOBULIN that reacts with a specific ANTIGEN, and serves as part of a vital body-defence mechanism. Various reactions can occur between antigen and antibody. If the antigen is a TOXIN (as in snake venom, or as produced by bacteria causing, for example, botulism and tetanus), neutralizing antibodies are called antitoxins. If the antigen is adhering to the surface of a cell, antibodies called agglutinins cause clumping or AGGLUTINATION of cells, while another antibody type (lysins) cause disintegration or LYSIS of the cell in conjunction with COMPLEMENT. Other antibodies (opsonins) facilitate uptake of antigens by PHAGOCYTES in the blood, while precipitins cause soluble antigens to precipitate.
Antibodies are produced in the lymphoid tissues of the body, e.g. LYMPH NODES, by a type of LYMPHOCYTE called B-CELLS. Most antibodies are produced during exposure to an antigen, such a response being termed active immunity. Specific antibodies to rare or synthetic antigens can be manufactured as easily as those to common antigens. A few antibodies are produced even without the apparent presence of the appropriate antigen. Such ‘natural’ antibodies include several involved in blood grouping, e.g. A and B antibodies in the ABO BLOOD GROUP. Young mammals have limited capacity to produce antibodies in the first few weeks of life, but can obtain some passive immunity by receiving maternal antibodies via the mother's milk. This fact has been used to encourage human mothers to breast-feed their infants rather than bottle-feed. Most antibodies circulate in the blood and other body fluids, but most if not all body secretions also contain antibodies, mainly of the IgA type; See IMMUNOGLOBULIN.
an·ti·bod·y(Ab) (an'ti-bod-ē) Avoid the jargonistic use of the plural antibodies when the reference is to a single antibody species.
Patient discussion about Antibody
Q. what is anh cardiolipin antibody