Thirty healthy adult volunteers without identifiable high-risk behavior for HIV-1 are randomly assigned to receive vaccination with gp160 (50 mcg) according to one of the following schedules: Group 1 receives vaccine on days 0, 28, 56, and 140 and placebo on days 84 and 112; Group 2 receives vaccine on days 0, 28, 56, 84, and 112 and placebo on day 140. Subjects are followed for 1 year after the last injection. Per 05/13/94 amendment, 10 subjects at the St. Louis University site receive an additional boost 18-24 months after the last injection.