Seventy healthy volunteers are randomized to one of four groups. Groups A and D receive one initial immunization with HIVAC-1e followed by two boosts with subunit gp120 and Env 2-3, respectively, at months 8 and 12. Group B receives two immunizations with HIVAC-1e at months 0 and 8 followed by a single boost with subunit gp120 at month 12. Group C receives three doses of subunit gp120 only at months 0, 8 and 12. (Per 10/01/92 amendment, boosts with VaxSyn (gp160) have been eliminated.) Subjects are followed for 18 months.