Monoclonal antibodies to HBsAg: a study of their specificities for eight different HBsAg subtypes.

Spleens from high responder Biozzi mice immunized with purified HBsAg of adw2, adw4 and ayw3 subtypes respectively were fused with N5-1 mouse myeloma cells. Over 30 clones with anti-alpha activity were obtained (principally from fusion adw2) as well as numerous clones with restrictive anti-HBs reactivity. The aim of this study was to characterize 9 different monoclonal antibodies with restrictive reactivity in comparison to a monoclonal anti-alpha antibody. Two different techniques were used: immunodiffusion and enzymoimmunoassay. Already known specificities or common reactivity between some subtypes were found, as w4, subdivision of ayw3 subtype, antigenic determinant common to w4 and adr, absence of the same determinant in adw2 and ayw1, the 2 subtypes having the highest capacity to absorb anti-alpha. Other monoclonal antibodies indicated the presence of previously unidentified subtype specificities: one of them recognized all HBsAg with d determinant but also ayw4, another recognized all HBsAg with y determinant but also adr, 2 others recognized determinants present completely or partially (spur formation) in many subtypes, another one recognized ayw4 and adw4 but also adw2. The combination of new tools such as monoclonal antibodies and synthetic peptides should facilitate the analysis of HBsAg.