A PHASE I STUDY OF THE SAFETY AND IMMUNOGENICITY OF RGP120/HIV-1IIIB VACCINE IN HEALTHY ADULT SUBJECTS (NOTE: STUDY EXTENDED ONLY FOR SUBJECTS WHO HAVE PREVIOUSLY RECEIVED RGP120/HIV-1IIIB OR RGP120/HIV-1MN ON VEU 006 OR VEU 006 ROLLOVER STUDY):