Evaluation of previous patients who received doses of 40 or 80 mcg gp160 vaccine indicates that, although serum anti-gp160 antibody responses were detected, the level and duration of those responses were limited. A preliminary observation suggests that weak functional antibody responses may develop following the 18 month booster of 40 or 80 mcg; therefore, a dose of gp160 vaccine having potentially greater immunogenicity is of particular interest.

In the initial phase of the study, 20 healthy volunteers receive 640 mcg gp160 vaccine and 5 healthy volunteers receive alum placebo. At least 30 days later, 20 additional volunteers receive 1280 mcg gp160 vaccine and 5 volunteers receive placebo. Injections are given on days 0, 30, 180, and 365.

Inclusion Criteria

Patients must have:

• Normal history and physical exam.
• Negative for HIV infection by ELISA and Western blot (i.e., no reactivity at gp160, gp120, gp41, or p24).
• T4 count >= 800 cells/mm3.
• Normal chest x-ray and urinalysis.
• Negative hepatitis B surface antigen.
• Negative HIV p24 antigen test.
• Normal skin reactivity by Merieux test.

Exclusion Criteria

Co-existing Condition:

Subjects with the following symptoms or conditions are excluded:

• Positive PPD.
• Syphilis, gonorrhea, or any other sexually transmitted diseases (including chlamydia or pelvic inflammatory disease).

Subjects with the following prior conditions are excluded:

• History of immunodeficiency, chronic illness, or use of immunosuppressive medications.
• Syphilis, gonorrhea, or any other sexually transmitted diseases (including chlamydia or pelvic inflammatory disease) in the past 6 months.

Prior Treatment:

Excluded:

• Prior blood transfusions or cryoprecipitates within the past 6 months.

Identifiable high-risk behavior for HIV infection (as determined by prescreening questions designed to identify risk factors for HIV infection), including:

• Any history of IV drug use.
• Syphilis, gonorrhea, or any other sexually transmitted diseases (including chlamydia or pelvic inflammatory disease) in the past 6 months.
• More than two sexual partners, or sexual contact with a high-risk partner, in the past 6 months.