In this study, 68 HIV-negative healthy adult volunteers, 21-55 years old, all belonging to the "Volunteers for a Vaccine" network set up by ANRS, were randomized to receive at weeks 0, 4, and 12, either 3 IM doses of 0.5 ml of LIPO-4 containing 500 µg of each peptide (n= 35 volunteers), or 3 ID doses of 0.1 ml, containing 100 µg of each peptide (n=33 volunteers). Total follow-up was 48 weeks. Safety was assessed clinically and by laboratory tests. Participants were given diary cards to record adverse events. HIV-1 immune responses were assessed by ELISPOT and lymphoproliferative assay at weeks 0, 2, 6, 14, 24, and 48