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humoral antibodyAn older, nonspecific term for an antibody found in the serum. Humoral antibody is increasingly used as an adjective, as in, primary humoral antibody response or secretory and humoral antibody response.
specialized serum proteins produced by B lymphocytes in response to an immense number of different antigens (>107) to which an animal may be exposed. Antibody produced by a particular antigen combines with that antigen only. The exquisite specificity of Ab for the antigen that stimulated its production is the basis for all antibody-antigen reactions both in vivo and in vitro. Antibodies are heterodimers composed of two light (L) and two heavy (H) chain polypeptide molecules. The amino termini of the L and H chains have a variable amino acid sequence VL and VH. The specificity of Ab for Ag is conferred by the VL and VH domains. There are five major classes of antibody, designated IgG, IgM, IgA, IgD and IgE. Abbreviated Ab or Ig. Called also immunoglubulin or gamma globulin. See also immunity.
affinity purification of antibody
antibody, usually IgE, formed after the first injection of certain allergens and responsible for the signs of anaphylaxis following subsequent exposures to the same allergen.
the specific combination of antigen with homologous antibody resulting in the reversible formation of antibody-antigen complexes that differ in composition according to the antibody-antigen ratio. See also antigen.
antinuclear antibody (ANA)
autoantibodies directed against components of the cell nucleus, e.g. DNA, RNA and histones; they may be detected by immunofluorescence. A positive ANA test is characteristic of systemic lupus erythematosus, Sjögren's syndrome and rheumatoid arthritis.
antibodies against the antibody variable region.
those produced against an immunoglobulin, often used as reagents to study immunoglobulin molecules.
see antiplatelet antibody.
produced following entry of sperm into the bloodstream, e.g. following rupture of the epididymis as in Brucella ovis infections.
circulating antibody (usually IgG) that reacts preferentially with an antigen, preventing it from reacting with a cell-bound antibody (IgE) and blocking the induction of anaphylaxis.
clone specific antibody.
see cold agglutinin.
immunoglobulins of the IgG or IgM class which bind complement.
one that combines with an antigen other than, but structurally related to, the one that induced its production.
cytotropic antibody (below).
that which binds antigens expressed on the cell surface, which may (a) activate the complement pathway or (b) activate killer cells, resulting in cell lysis.
those that attach to tissue cells (such as IgE to mast cells and basophils) that have an Fc receptor.
antibody-dependent cell-mediated cytotoxicity (ADCC)
a cytotoxic reaction in which nonsensitized cells bearing Fc receptors recognize target cells that have antibody bound to antigen exposed in the cell membrane of the target cell.
see fluorescence microscopy.
one with greater affinity for an antigen other than the one that stimulated its formation.
has been investigated mostly as a means of controlling fertility in animals. See also contraception.
see humoral immunity.
one induced by immunization or by transfusion incompatibility, in contrast to natural antibodies.
an antibody which combines with antigen without producing an observable reaction such as agglutination; originally used to describe Rh antibodies.
those passively transferred from dam to fetus or neonate, transplacentally or via colostrum or yolk sac. See also passive immunity.
damage to cells, especially erythrocytes, caused by the reaction of antibodies (IgG, IgM or IgA) with cell surface antigens.
see monoclonal antibodies.
ones that react with antigens to which the individual has had no known exposure. The best examples are anti a and b antibodies present in serum of humans of blood group B and A, respectively.
one that reduces, destroys or blocks infectivity of an infectious agent, particularly virus, by partial or complete destruction of the agent.
see incomplete antibody (above).
a collection of immunoglobulins that react against the same or different antigenic determinants of the one antigen molecule.
one responsible for immunity to an infectious agent.
all the antibody specificities that can be produced by an individual.
see incomplete antibody (above).