Reduction of Stat3 levels in CD4 T cells has no effect on Foxp3 expression from both thymi and spleens. (A) Foxp3 expression was analyzed in CD4 SP thymocytes by flow cytometry. (B) The mean proportion of CD4 SP thymocytes, the mean percentage of Foxp3⁺ CD4⁺ T cells, the average total numbers of thymocytes, and the absolute numbers of Foxp3⁺ CD4 T cells in thymocytes are shown. (C) Foxp3 expression was analyzed in CD4⁺ splenocytes by flow cytometry. (D) The average proportion of CD4⁺ SP splenocytes, the mean percentage of Foxp3⁺ CD4⁺ T cells, the average total numbers of splenocytes, and the absolute numbers of Foxp3⁺ CD4 T cells are shown. Means ± SE (n = 5) are shown. In panels A and C, numbers indicate the percentage of FoxP3⁺ cells delineated by the rectangles.