Recipients of allogeneic BM and irradiated allogeneic splenocytes had mixed donor and host type hematopoiesis. The mean percentage of peripheral blood leukocytes expressing H2^b(donor type; ▪) or H2^k (host type; □) from B10.BR (H2^k) mice surviving to day +30 after transplantation with C57.BL6 (H2^b) BM and irradiated (7.5 Gy) splenocytes is shown. The conditions of the transplant are described in the legend to Fig 6. The error bars depict the SD of the mean.