Immunization against the human immunodeficiency virus in Zaire

The first experimental immunization of human against the AIDS retrovirus HIV-1 was started in a series of HIV seronegative healthy volunteers in november 1986. Priming used a vaccinia virus recombinant (V25) expressing Gp 160 env determinants of HTLV III B at the surface of infected cells. This priming which induced a weak immune reaction was performed on HIV seronegative French and Zaïrian individuals living in Zaïre (Kinshasa). These results prompted to boost the primary immune response. Four different protocols were used: slow drip intravenous infusion with paraformaldehyde fixed autologous cells infected with V25 (first protocol), repeated scarification with V25 for the second protocol. The third protocol used scarifications with fragment of Gp 120 env protein, and the fourth protocol used intramuscular injections of purified autologous cell membrane infected with V25. Results of the immune reaction obtained after these boosts: The three last protocols showed a cell mediated immunity (CMI) that not significantly enhanced in comparison with CMI obtained after V25 priming alone. Moreover, the sera showed low and variable neutralizing antibodies titers one to four months after boosting. By contrast boosting with V25 infected fixed cells (D.Z. individual) provide strong humoral and cellular group specific anamnestic immune response. Indeed, high levels of antibodies to viral envelope and neutralizing antibodies against divergent HIV-1 strains were observed. Group specific CMI and cell mediated cytotoxicity were enhanced by boosts. Skin-tests showed high mediated and delayed hypersensitivity to GP 160 in vivo. For the first time, these results show that an immune stage against HIV can be obtained in a man.