Inclusion Criteria

Subjects must have:

• HIV negativity by ELISA.
• Normal history and physical exam.
• CD4 count >= 400 cells/mm3.
• Lower risk sexual behavior.
• Normal urine dipstick with esterase and nitrite.

PER AMENDMENT 3/6/96:

• Extension study -
• Consenting Protocol 015 volunteers who have received four immunizations.

Exclusion Criteria

Co-existing Condition:

Subjects with the following symptoms or conditions are excluded:

• Hepatitis B surface antigen.
• Active syphilis. NOTE:Subjects for whom serology is documented to be a false positive or due to a remote (> 6 months) treated infection are eligible.
• Active tuberculosis. NOTE:Subjects with a positive PPD and normal chest x-ray showing no evidence of TB and not requiring isoniazid therapy are eligible.
• Medical or psychiatric condition or occupational responsibilities that would preclude compliance.

Subjects with the following prior conditions are excluded:

• History of immunodeficiency, chronic illness, or autoimmune disease.
• History of anaphylaxis or other serious adverse reactions to vaccines.

PER AMENDMENT 3/6/96: Extension study -

• History of eczema or allergic-type reactions to vaccine in Protocol 015.

Prior Medication:

Excluded:

• Live attenuated vaccines within 60 days prior to study entry. (NOTE: Medically indicated subunit or killed vaccines, such as influenza or pneumococcal, are allowed but should be given at least 2 weeks prior to HIV immunizations.)
• Experimental agents within 30 days prior to study entry.
• Prior HIV vaccines.

PER AMENDMENT 3/6/96: Extension study -

• Use of systemic steroids in the past month.

Prior Treatment:

Excluded:

• Blood products or immunoglobulin within 6 months prior to study entry. Higher risk behavior for HIV infection (as determined by screening questionnaire), including history of injection drug use within the last 12 months and higher or intermediate risk sexual behavior.