title: Monoclonal IgM radioimmunoassay for hepatitis B surface antigen: high binding activity in serum that is unreactive with conventional antibodies.
abstract: Using a monoclonal IgM antibody (anti-HBs) to hepatitis B surface antigen (HBsAg) in a radioimmunoassay for hepatitis B, we have detected high binding activity in human serum that was unreactive in assays employing conventional anti-HBs reagents. The binding material was isolated from serum by affinity chromatography on monoclonal IgM anti-HBs, and comparison of the material with HBsAg (by sodium dodecyl sulfate/polyacrylamide gel electrophoresis) demonstrated that the two shared several similar polypeptides. Furthermore, comparison of the binding properties of HBsAg and concentrated monoclonal immunoreactive material with conventional and monoclonal anti-HBs reagents demonstrated some antigenic crossreactivity. The molecular weight of the monoclonal immunoreactive material was approximately 2 X 10(6). Immunoprecipitation of the material with monoclonal IgM antibodies and examination by electron microscopy revealed clumped and "spiculated" particles that resembled 22-nm hepatitis B particles coated with the same antibody. Thus, this study suggests that the high-binding-activity material, detected in serum only by the monoclonal radioimmunoassay, is not identical with HBsAg, but it shares some common properties.
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D006510:Hepatitis B Antibodies / Q000276:immunology*; D006511:Hepatitis B Antigens / Q000032:analysis / Q000276:immunology*; D006514:Hepatitis B Surface Antigens / Q000032:analysis / Q000276:immunology*; D006801:Humans; D007075:Immunoglobulin M; D008297:Male; D008970:Molecular Weight; D010455:Peptides / Q000032:analysis; D011863:Radioimmunoassay
chemical_list: D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D006510:Hepatitis B Antibodies; D006511:Hepatitis B Antigens; D006514:Hepatitis B Surface Antigens; D007075:Immunoglobulin M; D010455:Peptides