Lipopeptides induce cell-mediated anti-HIV immune responses in seronegative volunteers

Objective: Test the efficacy of a mixture of six NEF (N1, N2, N3), GAG (G1, G2) and ENV (E) lipopeptides in the induction of B- and T-cell anti-HIV responses. Design: A randomized phase 1 open-label dose-finding trial. Twenty-eight healthy seronegative volunteers received the lipopeptides, with or without the adjuvant QS(21). Methods: Anti-HIV-peptide antibodies were detected by enzyme-linked immunosorbent assay and Western blotting. Induction of cellulary responses was assessed by proliferative test and Cr-51-release assay. Results: Local and systemic adverse reactions were always mild or moderate. After three injections an antibody response was detected in 25 out of 28 volunteers (89%). T cells from 19 (79%) of the 24 volunteers proliferated in response to at least one peptide. The majority of the volunteers had induced a multispecific proliferative response; that is, cells from volunteers proliferated to two (five of 19), three (five of 19), four (three of 19) or five peptides (one of 19). Cytotoxic responses by anti-HIV CD8+ lymphocytes could be tested in 24 volunteers, 13 (54%) of whom had clear and reproducible responses, with strong activity in the remaining 12 (> 20% of specific lysis), and polyepitopic responses were detected in at least seven of the 13 responders. Cytotoxic responses were found against the whole NEF protein (clade B LAI) in three of four tested volunteers and cross-reactions with the proteins of clade B (MN) and clade A (Bangui) HIV-1 strains, and also HIV-2 ROD, were detected in one of two tested volunteers. Conclusions: Lipopeptides are promising immunogens for an AIDS vaccine. (C) 2001 Lippincott Williams & Wilkins.