1. Evaluate and characterize the cellular immune responses of nonhuman primates that have been immunized with HIV or SIV vaccines and/or infected with HIV, SHIV, or SIV2. Perform assays to evaluate and characterize immune responses at mucosal sites in nonhuman primates immunized with HIV or SIV vaccines or infected with HIV, SHIV, or SIV. 3. Develop new or more sensitive assays to detect and evaluate cellular immune responses in immunized and/or infected animals, including assays to detect mucosal immune responses, in order to maintain the capability of providing state-of- the-art assays under this contract. Improve current assays as needed to meet the scope of work