Figure 5.

Foxp3⁺ CD25^high CD127^low CD4⁺ T cells (CD4⁺ Tregs) and Foxp3⁺ CD25^high CD127^low CD8⁺ T cells (CD8⁺ Tregs) responsiveness to IL-2 and their comparative CD25 cell surface expressions. (A) Total fresh blood from healthy donors was ex vivo stimulated with different doses of IL-2 for 10 min, and STAT5 phosphorylation was measured on different T cell subsets. Results are expressed in mean ± SE, n = 7–22. Low-dose IL-2 has been defined as the dose inducing high STAT5 phosporylation on CD4⁺ Tregs but not on CD4⁺ Teff. (B) Mean fluorescence intensity (MFI) of CD25 on CD4⁺ Tregs and CD8⁺ Tregs (n = 37) from fresh unstimulated whole blood from healthy donors. Individual values and mean ± SEM are shown.