HIV-1 antigens generate in man both a humoral and cellular immune reaction. However, in ARC/AIDS patients, the cellular response is inhibited by HIV-1 which induces an antiproliferative (suppressive) effect on activated T cells. To overcome this inhibition and up-regulate the cellular response, we designed a new vaccine strategy directed both against HIV-1 and immunosuppression and we used an immunizing preparation composed of HIV-1 antigens combined with immunoregulatory peptides prepared in a biologically inactivated but immunogenic form. In mice, this preparation induced anti-HIV-1 antibodies and a cell-mediated cytotoxicity directed against H2 restricted cells carrying HIV-1 antigens.