Fifty-five healthy HIV-positive volunteers are randomly assigned to one of the following treatment arms: six injections (arm I) or four injections (arm II) of HIV-1 gp160 vaccine, four injections of hepatitis B vaccine as a non-HIV viral vaccine control (arm III), or six placebo injections consisting of the adjuvant vehicle used for the gp160 vaccine (arm IV). Immunizations or placebo are given at 4-week intervals for 5 months. To maintain blinding, adjuvant vehicle placebo is administered on days 84 and 112 to those volunteers receiving four instead of six vaccine injections (arms II and III). Volunteers are followed at 4-month intervals for 2 years.