Systematic identification of T-cell activating epitopes on the human immunodeficiency virus type 1 envelope glycoprotein gp120 in primates immunized with synthetic peptides.

Because T-cell responses are critical for defence against viral infections, an ideal vaccine should stimulate these cells. The authors have examined a series of forty overlapping synthetic peptides covering the entire amino acid sequence of the envelope protein gp120 from the human immunodeficiency virus type 1 (HIV-1) HTLV-IIIB isolate, for harbouring putative T-cell recognition sites. The peptide-induced proliferative responses and IL-2 production by blood mononuclear cells were studied from 40 macaques previously immunized with ovalbumin-conjugated HIV-1 peptide(s). These analyses disclosed four major areas of T-cell recognition, including one novel T-cell activating region (located between amino acids 152 and 176) which was also found to harbour a domain recognized by HIV-1 neutralizing antibodies. Recognition of the latter region by CD4+ T cells did not appear to be subject to strong genetic restriction. The results of these studies have obvious implications for the development of synthetic subunit vaccines against the acquired immunodeficiency syndrome (AIDS).