AIDS Clinical Trials Group (ACTG) 246/946 was a double-blinded, randomized, controlled trial of HIV-1 MN rgp160 ImmunoAG vaccine in HIV-infected patients with CD4(+) T cell counts >or=500 and 200-400/mm(3). The main objectives were to study the safety and immunogenicity of this vaccine and to study the persistence of the immune responses after vaccination over a longer period of time. Fifteen patients with CD4(+) T cell counts of >or=500/mm(3) were enrolled in the ACTG 246 study. ACTG 246 patients received a monthly injection of vaccine or control for 6 months and then injections every 2 months. After completion of this study, seven new patients with CD4(+) T cell counts of 200-400/mm(3) entered into the ACTG 946 study. These study patients received highly active antiretroviral therapy (HAART) (ritonavir, didanosine, and stavudine) for 9 weeks to stabilize their viral load and then each patient received a monthly injection of vaccine or control substance for 6 months with HAART. The study of these two relatively small populations showed that the vaccine was safe without any adverse effect both in the patients with CD4(+) T cell counts of >or=500 and 200-400/mm(3). The vaccine was also immunogenic in patients with CD4(+) T cell counts of >or=500/mm(3) as measured by gp160-specific lymphocyte proliferative responses, and it persisted after they had received more than six vaccine injections, for a longer period of time.