Description:
Abstract Thymocytes and bone marrow cells from normal mice or from mice primed with SRBC were used to repopulate heavily irradiated mice. The recipients were challenged with SRBC and the PFC formed in their spleens were enumerated. The thymus-marrow synergism characteristic of unprimed cells was not found when primed cells were used in the restoring inoculum. Thymocytes and marrow cells from primed mice were each capable of restoring immunocompetence in the recipients, and in contrast with the corresponding cells from unprimed animals they appeared to react immunologically as independent units.