The purpose of this study is to determine the safety of and immune response to an adenoviral vector HIV vaccine or a DNA HIV vaccine, each followed by an adenoviral vector HIV vaccine boost, in HIV uninfected adults.

Evaluating the immunogenicity of HIV vaccines is critical to improving vaccine design and development. The adenoviral vector HIV vaccine VRC-HIVADV014-00-VP has shown immunogenicity in early studies and appeared safe and well tolerated at three different doses in a prior dose-escalation vaccine trial in HIV uninfected adults. The DNA HIV vaccine VRC-HIVDNA009-00-VP has shown immunogenicity in multiple clinical trials; in one trial, the DNA vaccine demonstrated a nearly 100% CD4 T-cell response rate. The DNA plasmids in both vaccines code for proteins from HIV subtypes A, B, and C, which together represent 90% of new HIV infections. This study will determine the safety and immune response to the administration of an adenoviral vector HIV vaccine or a DNA HIV vaccine, each followed by an adenoviral vaccine boost, in HIV uninfected adults.

This study will last 1 year. Participants will be randomly assigned to one of two groups. Within each group, participants will be randomly assigned to receive either vaccine or control injections. Group 1 participants will receive either placebo or the adenoviral HIV vaccine at study entry and Month 6. Group 2 participants will receive either placebo or the DNA HIV vaccine at study entry and Month 1 and the adenoviral HIV vaccine at Month 6. Participants will be asked to record their temperatures and other side effects in a symptom log on the day of each vaccination and for 3 days thereafter to report any side effects.

Group 1 participants will have 16 study visits, and a physical exam and HIV and pregnancy prevention counseling will occur at each visit. Participants will also be asked about any side effects and medications they are taking. Blood collection will occur at most visits. Urine collection will occur at selected visits. Participants will be asked to complete a social impact assessment at Months 2, 6, and 12 and a testing and belief questionnaire at Months 6 and 12.

Inclusion Criteria:

• HIV uninfected
• Good general health
• Pre-existing adenovirus 5 (Ad5) neutralizing antibody titers of less than a 1:12 ratio
• Hepatitis B surface antigen negative
• Anti-hepatitis C virus (anti-HCV) antibody negative or negative HCV PCR if anti-HCV antibody is positive
• Have access to a participating HIV Vaccine Trials Unit (HVTU) and are willing to be followed during the study
• Willing to receive HIV test results
• Understand the vaccination procedure
• Willing to use acceptable forms of contraception

Exclusion Criteria:

• HIV vaccines or placebos in prior HIV trial. Participants who can provide documentation that they received a placebo in a prior HIV trial may be eligible.
• Immunosuppressive medications within 168 days prior to first study vaccination
• Blood products within 120 days prior to first study vaccination
• Live attenuated vaccines within 30 days prior to first study vaccination
• Investigational research agents within 30 days prior to first study vaccination
• Medically indicated subunit or killed vaccines within 14 days prior to first study vaccination
• Current anti-tuberculosis (TB) preventive therapy or treatment
• Clinically significant medical condition, abnormal physical exam findings, abnormal laboratory results, or past medical history that may affect current health. More information about this criterion can be found in the protocol.
• Any medical, psychiatric, or social condition that would interfere with the study. More information about this criterion can be found in the protocol.
• Any job-related responsibility that would interfere with the study
• Serious adverse reactions to vaccines, including hypersensitivity and related symptoms. A person who had an adverse reaction to pertussis vaccine as a child is not excluded.
• Autoimmune disease or immunodeficiency
• Active syphilis infection. Participants who have been fully treated for syphilis for more than 6 months prior to study entry are not excluded.
• Moderate to severe asthma. More information on this criterion can be found in the protocol.
• Type 1 or type 2 diabetes mellitus. Participants with histories of isolated gestational diabetes are not excluded.
• Thyroid disease or surgical removal of the thyroid requiring medication during the 12 months prior to study entry
• Accumulation of fluid in the blood vessels (angioedema) within 3 years prior to study entry if episodes are considered serious or have required medication in the 2 years prior to study entry
• Uncontrolled hypertension
• Body mass index (BMI) of 40 or greater OR BMI of 35 or greater if certain other criteria apply. More information about these criteria can be found in the protocol.
• Bleeding disorder
• Cancer. Participants with surgically removed cancer that is unlikely to recur are not excluded.
• Seizure disorder
• Absence of the spleen
• Mental illness that would interfere with the study
• Pregnancy or breastfeeding