T-cell recognition of pre-S regions of HBsAg can bypass nonresponse to the S region.

The objective of the studies reported herein was to identify and characterize T cell and B cell recognition sites within the pre-S regions of HBsAg/p39, and to analyze functional T-cell-B cell interactions at the level of in vivo antibody production. The results indicate: (1) several peptides within the pre-S(1) region of HBsAg were identified which can induce and elicit HBsAg/p39-specific T-cell proliferation; (2) a 10 amino acid peptide, p12-21, and the 94-117 sequence define pre-S(1)-specific T-cell recognition sites; (3) five distinct, pre-S(1)-specific antibody binding sites and 2 pre-S(2)-specific antibody binding sites were identified; (4) synthetic pre-S(1) region T-cell determinants can prime in vivo antibody production to multiple B-cell epitopes within the pre-S(2) and S regions, as well as within the pre-S(1) region; and (5) specificity of the primed T cell population can influence the specificity of the B-cell response.