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[anti- + body]
ABBR: 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 (antibodies to different blood types), are made by B cells stimulated by a foreign antigen, typically a foreign protein, polysaccharide, or nucleic acid.
SYN: SEE: immunoglobulin
ANTIBODY Structure of one igG molecule; SEE: antigen; SEE: autoantibody; SEE: cytokine; SEE: isoantibody
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.
ANTIBODY Schematic structure of immunoglobuin G antibody