This study is being conducted in two parts: Part A examines the safety of the adjuvant MTP-PE/MF59 alone; Part B examines the safety and immunogenicity of Env 2-3 in combination with MTP-PE/MF59. In Part A, three volunteers receive MTP-PE/MF59, and one volunteer receives emulsion alone at each dose level. Initiation of each dose level is separated by at least 72 hours. Doses of adjuvant emulsion are administered at day 0 and day 30 for the highest tolerated dose. If significant reactions are encountered, additional subjects may be studied at lower doses. In Part B, six doses of MTP-PE adjuvant (0, 5, 10, 25, 50, or 100 mcg) in the MF59 emulsion are studied. Six volunteers receive Env 2-3/MTP-PE/MF59 and two receive MTP-PE/MF59 alone at each dose level. There is a minimum 1-week interval between dose escalations. Per amendment, volunteers may receive an additional dose of Env 2-3 or placebo in MF59 emulsion only, administered 12-18 months post initial inoculation.