BCL2-mediated rescue of defective thymopoiesis in adult Flt3l^−/−Il7r^−/− mice. (A) Mean (SD) thymic cellularities, (B) FACS profiles of DN staging, and mean (SD) numbers of (C) DN1, (D) DN1KIT⁺, (E) DN2, (F) DN2KIT⁺, (G) DN3, (H) DN4, (I) DP, (J) CD4 SP, and (K) CD8 SP cells in the thymus of 7- to 9-week-old WT, Flt3l^−/−, Il7r^−/− and Flt3l^−/−Il7r^−/− mice on WT or BCL2 transgenic background. Data are from 3 to 4 WT, 12 Flt3l^−/−, 8 to 12 Il7r^−/−, 4 to 10 Flt3l^−/−Il7r^−/−, 7 to 9 BCL2, 14 Flt3l^−/−BCL2, 12 Il7r^−/−BCL2, and 6 to 7 Flt3l^−/−Il7r^−/−BCL2 mice, in all cases from at least 2 separate litters. Numbers in FACS profiles show the mean percentage (of total thymocytes) of cells within the indicated gates. For each strain and cell type, cutoff numbers in graphs are indicated. However, for one mouse in the Flt3l^−/−Il7r^−/− group, in which no DN1KIT⁺ and DN2KIT⁺ cells were detected, too few events were acquired to be applicable to the cutoff value.