Expression of activation markers in IL-7^–/– T cells. (A) Representative flow cytometric analysis of the expression of CD62L (top panel) and CD69 (bottom panel) in splenic CD4⁺CD25^– T cells of B6 (dashed line) and IL-7^–/– (bold line) mice at 28 weeks of age. (B) Absolute numbers of naive (top panel) and activated (bottom panel) splenic CD4⁺CD25^– T cells in B6 (•) and IL-7^–/– (○) mice at the indicated ages. Mean (± SD) from groups of 3 to 6 mice per time point is shown. (C) Representative flow cytometric analysis for CD62L (top panel) and CD69 (bottom panel) of splenic CD4⁺CD25⁺ T cells in B6 (dashed line) and IL-7^–/– (bold line) mice at 28 weeks of age. (D) Absolute numbers of resting (top panel) and activated (bottom panel) splenic CD4⁺CD25⁺ T cells in B6 (•) and IL-7^–/– (○) mice are represented at the indicated ages. Mean (± SD) of groups of 3 to 6 mice per time point is shown. The differences between the number of control and IL-7^–/– cells were statistically significant (P < .05) for all age groups, in all cases.