The above results prompted us to examine the proportion of CD4 + CD25 + Foxp3 + and CD8 + CD25 + Foxp3 + Tregs. To this end, splenic T cells isolated from each group of recipient mice were stained for intracellular Foxp3 after co-staining with anti-CD4/ CD25 antibodies or anti-CD3/CD8/CD25 antibodies, and the cells were next analyzed by flow cytometry. A significant increase of CD4 + CD25 + Foxp3 + and CD8 + CD25 + Foxp3 + Tregs was observed in recipients treated with Flt3L and Rapa as compared with recipients in other groups (Fig. 3 ).