Continued proliferation of transplanted rat lymphoid cells in irradiated mice.

An investigation was made of the nature of lymphoid cells in radiation chimaeras resulting from transplantation of rat bone marrow to whole-bcdy irradiated mice. The method of unstained cell counts was employed to identify mouse cells by the specific cytatoxic action of rat antimouse sera. Results indicate that a successful heterologous bone marrow transplantation is accompanied by a repopulation of the lymph glands with donor type cells. The identity of the lymphoid cells seemed to be closely linked to that of the other hematopoietic cells. (C.H.)