The primary activity of the contract will be the virological evaluation of therapies/strategies, alone and in combination, including (i) antiviral agents (drugs and biologics), (ii) immune-based therapies, (iii) novel gene-based therapies and (iv) transmission inhibitors in specialized assays. A secondary activity will be the production of standardized reagents (e.g., panel of drug resistant virus variants) generated during the course of these studies.