Inclusion Criteria

Concurrent Medication: Required:

• Omeprazole given concurrently in patients receiving the oral vaccine dose.

Volunteers must have:

• HIV-1 negativity.
• Normal history and physical exam.
• Lower risk for HIV infection.
• CD4 count >= 400 cells/mm3.
• Normal urine dipstick with esterase and nitrite.

NOTE:

• No more than 10 percent of volunteers may be over age 50.

Exclusion Criteria

Co-existing Condition:

Volunteers with the following conditions are excluded:

• Positive for hepatitis B surface antigen.
• Medical or psychiatric condition (including recent suicidal ideation or present psychosis) that precludes compliance.
• Occupational responsibilities that preclude compliance.
• Active syphilis (NOTE: If serology is documented to be a false positive or due to a remote (> 6 months) infection, subject is eligible).
• Active tuberculosis (NOTE: Subjects with a positive PPD and normal x-ray showing no evidence of TB and who do not require INH therapy are eligible).

Volunteers with the following prior conditions are excluded:

• History of immunodeficiency, chronic illness, malignancy, autoimmune disease, or use of immunosuppressive medications.
• History of cancer unless surgically excised with reasonable assurance of cure.
• History of suicide attempts or past psychosis.
• History of anaphylaxis or other serious adverse reactions to vaccines.
• History of serious allergic reaction requiring hospitalization or emergent medical care.

Prior Medication:

Excluded:

• Prior HIV-1 vaccines or placebo in an HIV vaccine trial.
• Live attenuated vaccines within the past 60 days. NOTE: Medically indicated subunit or killed vaccines (e.g., influenza, pneumococcal) do not exclude but should be administered at least 2 weeks prior to HIV immunizations.
• Experimental agents within the past 30 days.

Prior Treatment: Excluded:

• Blood products or immunoglobulin within the past 6 months.

Higher risk behavior for HIV infection as determined by screening questionnaire, including:

• History of injection drug use within the past year.
• Higher or intermediate risk sexual behavior.