Group 1: low-dose MN rsgp120/HIV-1 plus QS-21 (13 volunteers). Group 2: high-dose MN rsgp120/HIV-1 plus QS-21 (13 volunteers). Group 3: AIDSVAX B/E (injection contains each of the two vaccine components, HIV-1 MN rgp120 and A244 rgp120/HIV-1) plus QS-21 plus alum (13 volunteers).