Repopulation in lethally irradiated secondary recipients following transfer of BMCs from irradiated and nonirradiated bones of the same chimeras 4 weeks after BMT. BMCs (9-10 × 10⁶) were injected to lethally irradiated (10 Gy) CD45.1 mice. Mean percentages of donor CD4 cells, CD8 cells, B cells, monocytes, and granulocytes are shown at the indicated time points. *P < .05 between the 2 groups. Error bars indicate SD.