Safety and Immunogenicity of pDNA Vaccines Expressing HIV M Group p24^Gag Conserved Elements and/or p55^Gag, Administered With IL-12 pDNA

This study will evaluate the safety, tolerability, and immunogenicity of two HIV-1 pDNA vaccines: p24CE1/2 pDNA and p55\^gag pDNA administered with IL-12 pDNA adjuvant, given by intramuscular (IM) injection with electroporation (EP), in healthy, HIV-uninfected adults. Participants will be randomly assigned to one of four groups: Group 1 Treatment, Group 1 Control, Group 2 Treatment, or Group 2 Control. Participants in Group 1 Treatment will receive p24CE1/2 pDNA and IL-12 pDNA at Day 0 and Month 1, then p24CE1/2 pDNA plus p55\^gag pDNA and IL-12 pDNA at Months 3 and 6. Participants in Group 1 Control will receive placebo (sodium chloride for injection) at Day 0 and Months 1, 3, and 6. Participants in Group 2 Treatment will receive p55\^gag pDNA and IL-12 pDNA at Day 0 and Months 1, 3, and 6. Participants in Group 2 Control will receive placebo (sodium chloride for injection) at Day 0 and Months 1, 3, and 6. Study visits will occur at Day 0, Week 2, and Months 1, 1.25, 1.5, 3, 3.5, 6, 6.25, 6.5, 9, and 12. Visits may include physical examinations and clinical assessments, blood and urine collection, optional stool collection, HIV testing, risk reduction counseling, and interviews/questionnaires. At Month 18, study staff will contact participants for follow-up health monitoring.