A Multicenter, Randomized, Placebo-Controlled, Double-Blind Trial to Evaluate the Safety and Immunogenicity of an HIV-1 Pseudovirion Vaccine

Inclusion Criteria Patients must have: * Negative ELISA for HIV-1 antibody within 8 weeks of initial immunization. * CD4 count \>= 400 cells/mm3. * Negative Hepatitis B surface antigen. * Normal history and physical examination. Exclusion Criteria Co-existing Condition: Patients with the following conditions and symptoms are excluded: * Medical or psychiatric condition or occupational responsibilities preclude compliance with the protocol. * Present psychosis. * Active syphilis (eligible if serology documented to be a false positive or due to remote, i.e., \> 6 months treated infection). * Active tuberculosis (eligible if positive purified protein derivative test and normal chest x-ray showing no evidence of TB and not requiring isoniazid therapy). * Hepatitis B antigenemia. Concurrent Medication: Excluded: Immunosuppressive medications. Patients with the following prior conditions are excluded: * History of immunodeficiency, chronic illness, malignancy, or autoimmune disease. * History of cancer unless there has been surgical excision followed by sufficient observation period to give a reasonable assurance of cure. * History of suicide attempts, recent suicidal ideation or who have past psychosis. * History of anaphylaxis or other serious adverse reactions to vaccines. * History of serious allergic reaction to any substance, requiring hospitalization or emergent medical care (e.g. Stevens-Johnson syndrome, bronchospasm, or hypotension). Prior Medication: Excluded: * Prior receipt of HIV-1 vaccines or placebo recipient in a previous HIV vaccine trial. * Use of experimental agents within 30 days prior to study. * Live attenuated vaccines within 60 days of study. * Medically indicated subunit or killed vaccines (e.g., influenza, pneumococcal) within 2 weeks prior to study. Prior Treatment: Excluded: Receipt of blood products or immunoglobulin in the past 6 months. Risk Behavior: Excluded: Volunteers having identifiable higher risk behavior for HIV infection as determined by screening questions designed to identify risk factors for HIV infection, specifically: * History of injection drug use within the last 12 months prior to enrollment. * Higher or intermediate risk sexual behavior as defined by the AVEG ( i.e., meeting the criteria for AVEG Risk Group C or D). Volunteers risk behavior for HIV infection will be determined upon information obtained from a questionnaire and from the AIDS Vaccine Evaluation Group (AVEG) risk behavior guidelines. NOTE: * Only those volunteers meeting the criteria for AVEG Risk Groups A and B will be enrolled in this study.