title: The specificity of antibodies to the F(ab')2 fragment of human IgG.
abstract: The specificity of IgG anti-F(ab')2 antibodies was examined by unfractionated sera of patients with rheumatoid arthritis and also with affinity-purified antibody preparations. Examination of the sera by an enzyme-linked immunosorbent assay, using pooled human F(ab')2 fragments absorbed to microtiter plates, revealed that IgG anti-F(ab')2 antibodies cross-react with human and rabbit IgG and rabbit F(ab')2. IgG anti-F(ab')2 antibodies were purified by affinity chromatography and, when tested by a fluid-phase inhibition enzyme-linked immunosorbent assay, were found to be of 2 types. One fraction, similar to pepsin agglutinator, reacted with human F(ab')2 fragment alone. The other fraction was cross-reactive with human IgG and yet failed to react with idiotopes on Fab or epitopes on Fc fragments. The IgG anti-F(ab')2 antibodies we purified had no reactivity toward a human immune complex prepared from tetanus toxoid and antitoxoid.
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000915:Antibody Affinity; D000918:Antibody Specificity; D002499:Centrifugation, Density Gradient; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G