MOLECULAR ANALYSIS OF THE MODULATORY FACTORS OF THE RESPONSE TO HBSAGIN MICE AS AN APPROACH TO HBV VACCINE ENHANCEMENT

Mice were injected with immune complexes containing the recombinant he patitis B surface antigen (HBsAg) vaccine (S + preS2) bound to differe nt monoclonal antibodies (mAbs), in order to determine whether an enha ncement of the response to a human vaccine could be obtained and obser ved. Enhancement and indifference were observed, as well as a decrease in immunogenicity. No relationship could be established between anp e ffect and affinity or isotypy of the bound mAbs. The preS2 region was rendered more immunogenic when an IgG2a mAb was bound to the S region of the HBsAg. The response to the S region was not modulated, whereas immunogenicity of the preS2 collinear region was decreased by antibody shielding. The mAb which was the most efficient as an enhancer of the antibody response also increased binding of the complexed immunogen t o antigen presenting cells. The binding of a human mAb to the sole S r egion, but not to the preS2 region, should be tested as a potentiating agent of the anti-preS2 human immune response.