Comparison of immune responses to a native viral antigen and a synthetic peptide derived from it: implications for vaccine development

Murine immune responses to the hepatitis B surface antigen (HBsAg) and a synthetic peptide derived from it were compared at the humoral level. Six of nine strains used responded to either peptide or HBsAg, though restriction profiles were not superimposable. Two of three strains non-responsive to HBsAg produced an antibody response on immunization with peptide which was cross-reactive with both peptide and HBsAg. In in vitro lymphocyte stimulation assays, lymphocyte from all six peptide-immunized mouse strains could be induced to proliferate on challenge with HBsAg. However, of the HBsAg-immunized groups, lymphocytes from only three of six responder strains proliferated on in vitro HBsAg challenge. Cumulatively, these results suggest that a vaccine formulation that includes both protein antigens and synthetic peptides derived from these proteins may be more effective at eliciting an immune response in a broader cross-section of target population