AMENDED 10/1/93: Selected patients on VEU 009 who received four previous injections will receive three additional injections on the study extension (VEU 009X), administered at weeks 72, 76, and 104. Patients who received 300 or 600 mcg MN rgp120 vaccine (eight patients per dosage) in the original portion of the study will be randomized to receive either 300 mcg MN rgp120 or 300 mcg IIIB rgp120 vaccine. Eight patients who previously received the MN/IIIB combination will again receive 300 mcg of both vaccines. Additionally, six patients who received placebo in the original portion will receive 300 mcg IIIB rgp120 vaccine. There will be nine clinic visits required for the study extension.