reaginic antibody


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ho·mo·cy·to·tro·pic an·ti·bod·y

antibody usually of the IgE class that has an affinity for tissues (notably mast cells) of the same or a closely related species and that, on combining with specific antigen, triggers the release of pharmacologic mediators of anaphylaxis from the cells to which it is attached; the tropism seems to depend on the Fc portion of the antibody molecule; in anaphylaxis in the guinea pig, the homocytotropic antibody involved is of the γG class.
Synonym(s): reagin (4) , reaginic antibody

reaginic antibody

[rē′əgin′ik]
an immunoglobulin E antibody that is more numerous in hypersensitive individuals. See also reagin, reagin-mediated disorder.

ho·mo·cy·to·tro·pic an·ti·bod·y

(hō'mō-sī-tō-trō'pik an'ti-bod-ē)
Antibody of the IgE class that has an affinity for tissues (notably mast cells) of the same or a closely related species and that, on combining with specific antigen, triggers the release of pharmacologic mediators of anaphylaxis from the cells to which it is attached.
Synonym(s): reaginic antibody.

reaginic antibody

An antibody, usually of the IgE class, that binds to MAST CELLS in people prone to acute ANAPHYLACTIC (Type I hypersensitivity) reactions. In association with the ANTIGEN, such as pollen grains, reaginic antibody causes release from the mast cells of HISTAMINE, LEUKOTRIENES, PLATELET ACTIVATING FACTOR and other agents responsible for the allergic reaction. Also known as reagin.

antibody

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
anaphylactic 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.
antibody-antigen reaction
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.
anti-idiotype antibody
antibodies against the antibody variable region.
anti-immunoglobulin antibody
those produced against an immunoglobulin, often used as reagents to study immunoglobulin molecules.
antiplatelet antibody
see antiplatelet antibody.
antispermatozoal antibody
produced following entry of sperm into the bloodstream, e.g. following rupture of the epididymis as in Brucella ovis infections.
blocking antibody
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.
antibody classes
clonotypic antibody
clone specific antibody.
cold-reacting antibody
see cold agglutinin.
complement-fixing antibody
immunoglobulins of the IgG or IgM class which bind complement.
cross-reacting antibody
one that combines with an antigen other than, but structurally related to, the one that induced its production.
cytophilic antibody
cytotropic antibody (below).
cytotoxic antibody
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.
cytotropic antibody
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.
fluorescent antibody
see fluorescence microscopy.
heteroclitic antibody
one with greater affinity for an antigen other than the one that stimulated its formation.
hormonal antibody
has been investigated mostly as a means of controlling fertility in animals. See also contraception.
humoral antibody
see humoral immunity.
immune antibody
one induced by immunization or by transfusion incompatibility, in contrast to natural antibodies.
incomplete antibody
an antibody which combines with antigen without producing an observable reaction such as agglutination; originally used to describe Rh antibodies.
maternal a's
those passively transferred from dam to fetus or neonate, transplacentally or via colostrum or yolk sac. See also passive immunity.
antibody-mediated cytotoxicity
damage to cells, especially erythrocytes, caused by the reaction of antibodies (IgG, IgM or IgA) with cell surface antigens.
antibody-mediated immunity
humoral immunity.
monoclonal antibody
see monoclonal antibodies.
natural a's
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.
neutralizing antibody
one that reduces, destroys or blocks infectivity of an infectious agent, particularly virus, by partial or complete destruction of the agent.
nonagglutinating antibody
see incomplete antibody (above).
polyclonal antibody
a collection of immunoglobulins that react against the same or different antigenic determinants of the one antigen molecule.
protective antibody
one responsible for immunity to an infectious agent.
reaginic antibody
antibody repertoire
all the antibody specificities that can be produced by an individual.
saline antibody
complete antibody.
skin-sensitizing antibody
see reagin.
univalent antibody
see incomplete antibody (above).

reaginic

pertaining to reagin.

reaginic antibody
immunoglobulin E.