title: Detection by radioimmunoassay of IgM class antibody to hepatitis B core antigen: a comparison of two methods.
abstract: A solid-phase radioimmunoassay (RIA) for IgM anti-HBc is described. The assay (anti-mu RIA) is based on the adsorption of IgM to a tube coated with sheep antibody to the human IgM mu-chain. The adsorbed immunoglobulin is assayed for anti-HBc activity. Positive reactions in the test are shown to be due to IgM antibody, and a confirmation blocking test is described. Reactivity of test sera can be quantitated by comparison with standard sera containing known levels of IgM anti-HBc. Sera assayed for IgM anti-HBc by both the anti-mu RIA and a method employing serum fractionation and competitive RIA gave similar results. Rheumatoid factor (RF) alone did not react in the anti-mu RIA, but reactivity could be generated in the presence of RF and preformed aggregates of IgG anti-HBc.
mesh_terms: D000914:Antibodies, Viral / Q000032:analysis*; D006509:Hepatitis B / Q000276:immunology; D006510:Hepatitis B Antibodies / Q000032:analysis*; D006512:Hepatitis B Core Antigens / Q000276:immunology*; D006514:Hepatitis B Surface Antigens / Q000032:analysis; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis*; D011863:Radioimmunoassay / Q000379:methods*; D012217:Rheumatoid Factor / Q000032:analysis
chemical_list: D000914:Antibodies, Viral; D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012217:Rheumatoid Factor