(ăn′tĭ-bŏd″ē)
[Pronunciation]
Abbreviation: Ab.

A substance produced by B lymphocytes in response to a unique antigen.
Each Ab molecule combines with a specific antigen to destroy or control it. All antibodies, except natural antibodies (e.g., antibodies to different blood types), are made by B cells stimulated by a foreign antigen, typically a foreign protein, polysaccharide, or nucleic acid.
SYN: immunoglobulin

Figure: ANTIBODY
Schematic structure of immunoglobulin G antibody



See: antigen; autoantibody; cytokine; isoantibody
Antibodies neutralize or destroy antigens in several ways. They can initiate lysis of the antigen by activating the complement system, neutralizing toxins released by bacteria, coating (opsonizing) the antigen or forming a complex to stimulate phagocytosis, promoting antigen clumping (agglutination), or preventing 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.

Subentries:
anti-DNase B antibody
antiendomysial antibody
antiganglioside antibody
antigliadin antibody
antineutrophil cytoplasmic antibody
antinuclear antibodies
antiphospholipid antibody
anti-proliferating cell nuclear antigen (PCNA) antibody
antireceptor antibody
anti-scl-70 antibody
antithyroperoxidase antibody
antititin antibody
anti-topoisomerase I antibody
blocking antibody
cross-reacting antibody
cytotoxic antibody
direct fluorescent antibody
fluorescent antibody
immune antibody
maternal antibody
monoclonal antibody
natural antibody
p504s antibody
polyclonal antibody
protective antibody
warm antibody