Survival of mice that received transplants with C/EBPα^-/- FL cells and host-derived radioprotective cells. (A) C/EBPα^+/+, C/EBPα^+/-, and C/EBPα^-/- FL cells were cotransplanted with host-derived radioprotective cells into lethally irradiated mice at cell doses described in “Materials and methods” and were monitored for survival. Photomicrographs of hematoxylin/eosin-stained sections from BM (i), spleen (iii), and liver (iv), and Giesema-stained peripheral blood smear (ii) of C/EBPα^-/- mice are at magnifications of × 400 and insert × 100.