Sites that bind polymerized albumin on hepatitis B surface antigen particles: detection by radioimmunoassay.
Antibodies to polymerized human albumin (poly-HSA) could not be detected by using sensitive methods (enzyme-linked immunosorbent assay and radioimmunoprecipitation) in sera from chronic carriers of hepatitis B surface antigen (HBsAg) or in serial bleedings from one chimpanzee infected with type A hepatitis virus and one infected with non-A, non-B hepatitis virus. By a solid-phase radioimmunoassay, receptor sites for poly-HSA could be detected on HBsAg particles from sera containing either hepatitis B "e" antigen (HBeAg) or anti-HBe. Blocking experiments showed that monomeric HSA did not bind to this receptor. In general, the HBsAg particles from sera with HBeAg had more poly-HSA receptor sites or relatively more particles carrying this receptor compared with HBsAg from sera with anti-HBe. Microtiter plates coated with poly-HSA bound HBsAg from sera containing HBeAg with greater efficiency than did anti-HBs coupled to a solid phase (Ausria II beads), whereas with sera positive for anti-HBe, the two assays were equally sensitive. Decreased ability of HBsAg to bind to poly-HSA was seen in some sera which had been stored for a few years at 4 degrees C, whereas the binding to anti-HBs was unaffected. It is possible that polymers of albumin on the surface of hepatocytes could function as receptors for hepatitis B virus.
D000818:Animals; D000906:Antibodies / Q000032:analysis; D001665:Binding Sites; D006509:Hepatitis B / Q000276:immunology; D006510:Hepatitis B Antibodies; D006511:Hepatitis B Antigens; D006514:Hepatitis B Surface Antigens / Q000032:analysis*; D006801:Humans; D002679:Pan troglodytes; D011108:Polymers; D011863:Radioimmunoassay; D012709:Serum Albumin / Q000276:immunology / Q000378:metabolism*
D000906:Antibodies; D006510:Hepatitis B Antibodies; D006511:Hepatitis B Antigens; D006514:Hepatitis B Surface Antigens; D011108:Polymers; D012709:Serum Albumin