Safety of an HIV DNA Vaccine Given to HIV Uninfected Adults

DNA vaccination has induced immune responses in animals to a number of viral, bacterial, and parasite derived antigens. Early clinical experiences with HIV DNA vaccines in humans indicate: 1) the tolerability and short-term safety of DNA at doses up to 5000 mcg in humans are excellent; and 2) there is potential for immunogenicity. The pGA2/JS2 DNA vaccine is part of a planned prime/boost regimen of a DNA vaccine prime followed by a modified vaccinia Ankara (MVA) vaccine boost. In studies in monkeys, a combination of a DNA vaccine and an MVA vaccine protected the monkeys against disease caused by a monkey virus similar to HIV. The current study is an initial investigation of the safety and immunogenicity of the DNA vaccine given alone. The pGA2/JS2 DNA vaccine expresses gag, protease, reverse transcriptase, env, tat, vpu, and rev. Participants are randomized to 1 of 2 groups. People in Group A receive either 2 injections of a lower dose (300 mcg) of the DNA plasmid vaccine or the placebo control. People in Group B receive either 2 injections of a higher dose (3000 mcg) of the DNA plasmid vaccine or the control. Group B will be enrolled only if the vaccine is found to be safe and well-tolerated during the initial 2-week evaluation of all participants in Group A. Participants receive vaccinations administered at Months 0 and 2. All vaccinations are administered by intramuscular (IM) injection in an outpatient setting. Participants have about 10 clinic visits during this study, including the screening and injection visits. Participants give blood and urine samples at study visits. They are tested for HIV before entering the study and 4 more times during the study. Women who can become pregnant may undergo up to 3 pregnancy tests during the study period.