Reduced thymocytes and thymic Foxp3⁺Treg cells in Mcl1^ΔFoxn1mice. (A) Flow cytometry plots of CD4 vs CD8 expression on thymocytes. Graphs represent the numbers of different thymocyte and DN subsets in the thymus. (B) Flow cytometry plots of CD4 vs FOXP3 gated on CD4 single positive thymocytes, with the proportion of cell bounded by regions indicated. Graphs show the proportion and number of thymic FOXP3⁺ Treg cells from controls and Mcl1^ΔFoxn1 mice at the indicated ages. Data representative of at least 2 independent experiments are shown (except Treg cell data for 2 months). Graph bars indicate mean ± SEM and groups were compared with a Student t test (2 sided, unpaired). **P < .01; ***P < .001; ****P < .0001. The control group combines various combinations of genotypes (Foxn1^Cre/+Mcl1^+/+, Foxn1^+/+Mcl1^lox/+, Foxn1^+/+Mcl1^lox/lox, Foxn1^Cre/+Mcl1^lox/+) that showed no differences from each other in separate experiments (n ≥ 3/group; where n represents the number of mice per group with each point denoting a mouse).