Class II (I-Ad) restricted T-cell recognition of the V3 loop region of HIV-1 gp120.

A CD4+ and gp120-specific T-cell line, and subclone, were established from BALB/c mice following immunization with recombinant gp120, using an adjuvant formulation (alum) acceptable for use in the human. The recognition specificity was determined against a panel of synthetic peptides corresponding to the primary sequence of the HXB2 strain of human immunodeficiency virus (HIV). An epitope was identified, corresponding to amino acid residues 322-341, and a further series of truncated peptides established the minimum determinant to be 327-341. Possible reasons for the immunodominance of the V3 loop, and adjacent regions, for both antibody and T-cell recognition are discussed.