DESCRIPTION: (Applicant's Description) Core B is designed as the mouse BMT core. It will provide a centralized service that will ensure smooth coordination with Project 1, as well as enhancing the ability of the principal investigators on Projects 2, 3, and 4 to perform bone marrow transplantations in a timely manner and with sufficient quality control of reagents, BMT conditioning, and therapeutic interventions. It will also ensure that experiments will be reproducible among all these projects. This core is central to the goal of the program project grant and ensures the coordination and integration of analyses of these projects into the program as a whole. This core realizes the various projects' efforts to sustain an experimentally interdependent program. In addition, because the expertise and administration is centralized, a significant economy of effort can be achieved with respect to technical protocols, as well as minimization of mouse purchasing and per diem costs.