B.63521

This study will evaluate the safety and tolerability (including reactogenicity) of candidate vaccine A244/B.63521 with Army Liposome Formulation (ALF) mixed with the saponin QS-21(Quillaja saponaria-21) (ALFQ) adjuvant. The purpose of this phase I randomized, double-blind clinical trial is to optimize vaccine adjuvant ALFQ dosing by assessing safety, reactogenicity, and immunogenicity. Safety and tolerability will be assessed with both clinical and laboratory monitoring. Sixty human immunodeficiency virus (HIV) negative participants will be enrolled to one of three arms. Vaccinations via intramuscular (IM) injection will occur at months 0, 1, and 2. All participants will receive A244 and B.63521 (300 micrograms of each). In addition, Arm 1 will receive 200 micrograms of ALFQ. Arm 2 will receive 100 micrograms of ALFQ. Arm 3 will receive 50 micrograms of ALFQ.