ORIGINAL DESIGN: Twenty-eight subjects will be randomized to receive 100 or 300 mcg rgp120/HIV-1IIIB vaccine (gp120 vaccine) or matching placebo. For each dose level, 10 subjects will receive vaccine and four subjects will receive matching placebo. Injections are given intramuscularly at 0, 4, and 32 weeks. Each subject receiving treatment at the lower dose level must be monitored for unacceptable toxicity for at least 2 weeks following the initial immunization before his or her second dose is administered and before treatment at the higher dose level begins. Subjects are followed for at least 12 months.