Immunogenicity of the gene S and Pre-S domains in hepatitis B virions and HBsAg filaments.

The three morphological forms (20-nm particles, filaments, virions) of hepatitis B surface antigen (HBsAg) were isolated from serum of chronic virus carriers or from transfected cell lines. BALB/c mice and guinea pigs were immunized with the antigens and the antibody responses against the three antigenic domains of the viral envelope were assayed. The proportion of pre-S1, pre-S2 and gene S antibodies was similar to the molar proportion of the domains in the immunogens. The major gene S and pre-S1 epitopes were conformational, and the major epitopes of the pre-S2 domain were sequential. The immunogenicity of natural and recombinant antigens was identical. The proportion of subtype-specific antibodies was high. The results suggest that recombinant HBsAg filaments containing both subtypes ad and ay may be optimal hepatitis B vaccines.