<qa>  What is the goal of the vaccine study?The goal of this vaccination study is to evaluate the safety and immunogenicity of the Therion Biologic Corporation Cambridge, MA TBC-3B vaccine. TBC-3B consists of live, recombinant vaccinia virus expressing the env and gagpol genes of HIV-1 strain IIIB. TBC-3B will be administered by subcutaneous injection in the groin and in the deltoid region, with the aim of determining which site is better at inducing mucosal immune responses. Because the groin area drains to the inguinal lymph nodes, vaccines given there may stimulate local immunologic activity in the draining rectal mucosa as well as systemic immunologic activity in the blood. 