<qa>  What is the first 2 months of the study?Volunteers will be followed for 20 months. The first 2 months of the study will be an evaluation of volunteers normal immune function. Volunteers will then be randomly selected to receive the TBC-3B experimental HIV vaccine in either the groin area or in the deltoid region. Neither volunteers nor study personnel will know which group the volunteer will be in until the day of the first immunization. All volunteers will receive TBC-3B. 