Anti-HBs antibody of normal human subjects predominantly binds 54 K and 60 K dalton HBs polypeptides.

The structure of hepatitis B virus surface antigen (HBs) recognized by anti-HBs antibody was analyzed by western blotting using anti-HBs sera obtained from normal subjects, from rabbits immunized with purified HBs and commercially available goat serum. The HBs used had 7 components of 24 K, 27 K, 33 K, 36 K, 39 K, 43 K and 67-72 K daltons. Goat anti-HBs serum bound all of these components, while human and rabbit anti-HBs sera bound only two components (60 K and 54 K daltons), which were hardly visible in the gel even by silver staining. Mixing the 24 K and 27 K components, and the 24 K and 43 K components without reducing reagent produced several polymerized forms of HBs components including 60 K and 54 K polypeptides, which were recognized by anti-HBs rabbit serum. Other combinations of HBs components did not yield any new polymeric forms. Thus, it was concluded that the formation of anti-HBs antibody in normal subjects might predominantly require an antigenic structure of polymeric forms of specific combinations of HBs polypeptides, other than previously known antigenic determinants.