Induction of CD8+ CTL activity is considered a critical property for a candidate vaccine. Additionally, since the majority of HIV-1 infections occur after inoculation of a mucosal surface, it is desirable to induce mucosal immunity as well as systemic immunity. The HIV p17/p24:Ty-VLP vaccine may potentially induce both CTL and mucosal antibody responses against HIV-1.~Volunteers receive HIV p17/p24:Ty-VLP vaccine or placebo by IM injection (with or without alum adjuvant) at months 0, 2, and 6, and then either by mouth or rectal enema at months 10 and 11. Volunteers who receive oral vaccine boosting will receive concurrent omeprazole to decrease stomach acid.
To evaluate the safety and immunogenicity of HIV p17/p24:Ty-VLP (virus-like particles) vaccine in uninfected volunteers. Specifically, to determine whether the vaccine formulated with and without alum induces CD8+ cytotoxic T lymphocytes ( CTLs ) that may be cross-reactive against multiple HIV-1 stains. Also, to determine whether boosting with the vaccine orally or rectally will help induce mucosal antibody responses.~Induction of CD8+ CTL activity is considered a critical property for a candidate vaccine. Additionally, since the majority of HIV-1 infections occur after inoculation of a mucosal surface, it is desirable to induce mucosal immunity as well as systemic immunity. The HIV p17/p24:Ty-VLP vaccine may potentially induce both CTL and mucosal antibody responses against HIV-1.