Evaluation of the safety and immunogenicity (immunological reactivity) of HIVAC-1e vaccine. An additional goal is to determine which dose level of vaccine might be most effective. Specific questions to be addressed in this part of the study include: Are there adverse reactions to gp160 vaccine when given to vaccinees previously immunized with a vaccinia-recombinant? Does gp160 vaccination of prior HIVAC-1e vaccine result in stimulation of neutralizing antibody and other humoral immune responses? Does vaccination with gp160 enhance the development of cell-mediated immune responses in HIVAC-1e vaccinees? Is the magnitude of immune response to gp160 booster immunization greater following priming with GP160 recombinant vaccinia (HIVAC-1e) vaccination than priming with three doses of purified recombinant gp160? AMENDED: An 80 mcg dose of gp160 has been chosen for the booster because this dose has been shown to be safe and immunogenic in previous trials and allows comparison of the late boost in this protocol with the late boost in the protocol in which patients were primed with three doses of gp160. Original design: HIVAC-1e vaccine is a preparation of the envelope protein of HIV (the virus that causes AIDS). The protein is produced by genetic modification in vaccinia virus. The purpose of a vaccine is to produce an artificially increased immunity to a particular disease, in this case, AIDS. Since there is no known cure for AIDS, the control of this disease necessitates the development of effective prevention such as vaccines.