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.