Enhancement of cellular immune response in HIV-1 seropositive individuals : A DNA-based trial

A DNA-based vaccine containing HIV-1 Env and Rev genes was tested for safety and host immune response in 15 HIV-infected asymptomatic patients with CD4-positive lymphocyte counts ≥500/μl of blood and receiving no antiviral therapy. Successive groups of patients received three doses of vaccine at 30, 100, or 300 μg at 10-week intervals in a dose-escalation trial. Some changes were noted in cytotoxic T-lymphocyte activity against gp160-bearing targets. Importantly, enhanced specific lymphocyte proliferative activity against HIV-1 envelope was observed in multiple patients. Three of three patients in the 300-μg dose group also developed increased MIP-1α levels which were detectable in their serum. Interestingly patients in the lowest dose group showed no overall changes in the immune parameters measured. The majority of patients who exhibited increases in any immune parameters were contained within the 300 μg, which was the highest dose group. These studies support further investigation of this technology for the production of antigen-specific immune responses in humans.