Splenic CD4⁺CD25⁺ T cells in IL-7^–/– mice. (A) Flow cytometric analysis of CD25 and FOXP3 expression on gated CD4⁺ T cells in splenic B6 (left panel) and IL-7^–/– (right panel) mice at 8 weeks of age. Mean (± SD) from groups of 3 to 6 mice is indicated. (B) Total number of splenic CD4⁺CD25⁺ T cells in B6 (•) and IL-7^–/– (○) mice is represented at the indicated ages. Diamonds represent the number of CD4⁺ FOXP³⁺ T cells. Mean (± SD) from groups of 3 to 6 mice per time point is shown.