Evaluate Tolerability of a Multi-envelope, Prime-boost HIV Vaccine in Healthy Adults

This is a research study to find out about the safety of a new potential vaccine regimen against HIV. This potential vaccine regimen consists of a sequence of six vaccine shots that are being studied to see if they can help to protect people from the human immunodeficiency virus (HIV). HIV infection is the cause of AIDS. AIDS is one of the most serious viral infections we know. Twenty million people around the world have already died of AIDS and over 40 million people are currently infected with the virus. This study is being done to help us find an HIV vaccine that works. Vaccines have been very successful in preventing other viral infections, such as hepatitis B, polio, and measles. Viral vaccines work by causing a person's immune system to make antibodies and immune cells against the virus or to "respond" to the virus. Because of the success with other viral infections, scientists are trying to develop a successful vaccine for HIV. If a person's immune system can respond to HIV before he or she is exposed to it, that person may be able to be protected from infection with HIV. The vaccine regimen that will be tested in this study is based on the information that the virus uses to make a small part of the HIV. This small part is called the "envelope" or coating around the virus. Because only the information for this one part of the virus is used in the vaccine, the vaccine cannot cause HIV infection. We make all parts of the vaccine regimen in test tubes.