Inclusion Criteria

Patients must have or be:

• Healthy.
• Negative ELISA for HIV.
• Negative for Hepatitis B surface antigen.
• Normal urine dipstick.
• Normal history and physical examination.
• Availability for 18 months of follow-up.

Risk Behavior: Required:

• Lower-risk sexual behavior as defined by AVEG.

Exclusion Criteria

Co-existing Condition:

Patients with any of the following symptoms or conditions are excluded:

• Medical or psychiatric condition or occupational responsibilities, which preclude subject compliance with the protocol (e.g., recent suicidal ideation or present psychosis).
• Active syphilis. NOTE: If the serology is documented to be false positive due to a remote (> 6 months) treated infection, the volunteer is eligible).
• Active tuberculosis. NOTE: Volunteers with a positive PPD and a normal chest X-ray showing no evidence of TB and not requiring INH therapy are eligible.

Patients with any of the following prior conditions are excluded:

• History of immunodeficiency, chronic illness, malignancy, autoimmune disease.
• History of cancer unless there has been surgical excision followed by a sufficient observation period to give a reasonable assurance of cure.
• History of anaphylaxis or history of other serious adverse reactions to vaccines.
• History of serious allergic reaction to any substance, requiring hospitalization or emergent medical care.
• History of suicide attempts or past psychosis.
• History of reaction to thimerosal.

Prior Medication:

Excluded:

• History of use of immunosuppressive medication.
• Live attenuated vaccines within 60 days of study. NOTE: Medically indicated subunit or killed vaccines (e.g., influenza, pneumococcal) are not exclusionary, but should be given at least 2 weeks away from HIV immunizations.
• Use of experimental agents within 30 days prior to study.
• Prior receipt of HIV-1 vaccines or placebo recipient in previous HIV vaccine trial.

Prior Treatment:

Excluded:

• Receipt of blood products or immunoglobulin in the past 6 months.

Risk Behavior:

Excluded:

• Subjects with identifiable higher-risk behavior for HIV infection as determined by screening questionnaire designed to identify risk factors for HIV infection.
• History of injection drug use within the last 12 months prior to enrollment.
• Higher- or intermediate-risk sexual behavior as defined by AVEG.