CYTOTOXIC T-CELL AND NEUTRALIZING ANTIBODY-RESPONSES TO HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 ENVELOPE WITH A COMBINATION VACCINE REGIMEN

Effective human immunodeficiency virus (HIV) vaccination may require i nduction of neutralizing antibodies (NAs) and CD8(+) cytotoxic T lymph ocytes (CTL) to prevent transmission and control early infection, Reco mbinant envelope proteins induce NAs but rarely CD8(+) CTL responses, and vaccinia vectors containing HIV-1 envelope elicit CD8(+) cytotoxic ity but few NAs, To benefit from both approaches, 56 vaccinia-naive su bjects were randomized to a regimen of priming with recombinant vaccin ia gp160(LAI) and boosting with recombinant gp120(SF-2), gp120(LAI), g p120(MN), or gp160(MN) Of 51 persons for whom assays were done, 26 dem onstrated envelope-specific CTL, Boosting with gp120, compared with gp 160, elicited significantly more NAs and CD4-blocking antibodies, Neut ralization of the homologous and heterologous HIV-1 laboratory strains occurred in all subjects receiving vac/env and gp120 and was detectab le in 91% of the subjects for >6 months, Thus, vaccine regimens in whi ch one component elicits primarily CTL and the other NAs offer promise for the development of an effective HIV-1 vaccine strategy.