A Phase I Safety and Immunogenicity Trial of HIV-1 gp120 C4-V3 Hybrid Polyvalent Peptide Immunogen Mixed in Mineral Oil Containing Mannose Mono-Oleate (IFA)

Inclusion Criteria Volunteers must have: * Negative ELISA for HIV within 8 weeks of immunization. * Normal history and physical examination. * Normal chest x-ray within 4 weeks prior to initial immunization. * Low-risk sexual behavior as defined by AVEG. Exclusion Criteria Co-existing Condition: Volunteers with the following conditions are excluded: * Medical or psychiatric condition that precludes compliance with the protocol, including recent suicidal ideation or present psychosis. * Occupational responsibilities which preclude compliance with the protocol. * Active syphilis (if the serology is documented to be a false positive or due to a remote \[more than 6 months\] treated infection, the volunteer is eligible). * Active tuberculosis (volunteers with a positive purified protein derivative and a normal chest x-ray showing no evidence of TB and not requiring isoniazid therapy are eligible). * Positivity for hepatitis B surface antigen. Volunteers with the following prior conditions are excluded: * History of immunodeficiency, chronic illness, malignancy, or autoimmune disease. NOTE: Individuals with a history of cancer are excluded unless there has been surgical excision followed by a sufficient observation period to give a 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 to any substance, requiring hospitalization or emergent medical care (e.g., Stevens-Johnson syndrome, bronchospasm, or hypotension). * History of lung disease. Prior Medication: Excluded: * Live attenuated vaccines within 60 days of study. NOTE: Medically indicated subunit or killed vaccines (e.g., influenza, pneumococcal) are not exclusionary, but should be given at least 2 weeks away from HIV immunizations. * Experimental agents within 30 days prior to study. * HIV-1 vaccines or placebo, received in a previous HIV vaccine trial. * Immunosuppressive medications. Prior Treatment: Excluded: * Receipt of blood products or immunoglobulin in the past 6 months. Risk Behavior: Excluded: * Alcohol intake greater than or equal to the equivalent of 1 oz of 100 proof per day (4 oz. glass of wine or 12 oz. of beer per day). * Identifiable higher-risk behavior for HIV infection as determined by screening questions designed to identify risk factors for HIV infection; specific exclusions include a history of injection drug use within the last 12 months prior to enrollment and higher- or immediate-risk sexual behavior as defined by the AVEG (i.e., meeting the criteria for AVEG Risk Groups C and D).