Inclusion Criteria

You may be eligible for this study if you:

• Are 18-50 years old.
• Are HIV-negative.
• Are healthy and have a normal history and physical exam.
• Agree to practice abstinence or use of effective birth control for 1 month before and during the study.

Exclusion Criteria

You will not be eligible for this study if you:

• Have a history of immune deficiency, chronic illness, or autoimmune disease.
• Have received immunosuppressive medications, blood products, trial drugs, immunoglobulins, or an HIV or typhoid vaccine.
• Have a history of severe allergic reactions.
• Have had prior suicidal attempts or have a psychiatric condition or job commitments which would prevent you from completing the study.
• Have a history of cancer (unless the cancer has been successfully cured), gallbladder disease, typhoid fever, migraines or other severe headaches, cardiac valve defects, or congenital heart disease.
• Have active syphilis or tuberculosis.
• Are allergic to certain medications.
• Are pregnant or breast-feeding.
• Have household contact with infants or persons who are pregnant, immunodeficient, or HIV-positive.
• Are unavailable for 12 months of follow-up.
• Have hepatitis B.
• Have a history of injection drug use within 12 months of enrollment or have higher or intermediate risk sexual behavior.