CD4-Cre⁺-Crry^flox/flox and Lck-Cre⁺-Crry^flox/flox mice developed peripheral T-cell lymphopenia. (A) Left: Representative flow cytometric analysis of thymocyte composition and CD4⁺, CD8⁺ T-cell populations in the spleens, lymph nodes, and blood of CD4-Cre⁻-Crry^flox/flox and CD4-Cre⁺-Crry^flox/flox littermates. Right: Numbers of total cells, B220⁺, CD4 SP (CD4⁺), and CD8 SP (CD8⁺) cells in the thymi, spleens, and lymph nodes of CD4-Cre⁻-Crry^flox/flox and CD4-Cre⁺-Crry^flox/flox littermates (n = 4 per group). Because blood collection varied in volume, the percentage, instead of total number, of B220⁺, CD4⁺, and CD8⁺ cells in the blood of the 2 groups of mice was shown. Values shown are mean plus or minus SEM. NS indicates not significant (P > .05). *P < .05, Student t test. (B) Data from Lck-Cre⁻-Crry^flox/flox and Lck-Cre⁺-Crry^flox/flox littermates (n = 4 per group). Analysis and data presentation are the same as in panel A.