Although recent advances have been made in antiviral therapy against AIDS, there is currently no cure for AIDS. It is likely that the ultimate control of the disease depends on the development of safe and effective vaccines against HIV.

Healthy, adult volunteers without identifiable high-risk behavior for HIV-1 infection are randomly assigned to receive three injections of either 200 mcg gp160 vaccine or a placebo. At each participating site, four volunteers receive vaccine and two volunteers receive placebo. Primary immunization and two booster immunizations at day 30 and day 180 are done in an outpatient setting. Volunteers are closely monitored for the first 2 weeks postimmunization (primary and boosters), and extensively followed for 2 years. Volunteers may be offered an additional booster of the same preparation at 12 months.

Inclusion Criteria

Patients must be:

• Normal, healthy, HIV-negative adults who fully comprehend the purpose and details of the study.
• Available for 2 years of follow-up.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions or symptoms are excluded:

• History of positive PPD (tuberculin test) and abnormal chest x-ray.
• Positive syphilis serology (e.g., RPR).
• Positive for circulating hepatitis B surface antigen.

Patients with the following are excluded:

• They or their sexual partners have identifiable high-risk behavior for HIV infection.
• History of immunodeficiency or chronic illness.
• Evidence of psychological or psychiatric problems that may lead to noncompliance.

Prior Medication:

Excluded:

• Immunosuppressive medications.

Prior Treatment:

Excluded:

• Blood transfusions or cryoprecipitates within the past 6 months.