The proportion of CD4+CD25+Foxp3+ Tregs was significantly increased in the peripheral blood of mice with STZ-induced diabetes for 4 months. PBLs of control and diabetic mice were collected at 10 days, 1 month and 4 months after onset of diabetes and stained for CD4, CD8, CD25 and Foxp3. (a) Representative FACS staining for CD4 and CD8 on PBLs as well as the percentages of CD4+ T cells (middle) and CD8+ T cells (right) in PBLs of control and diabetic mice at indicated time points. (b) The percentage of CD4+CD25+ T cells out of total CD4+ T cells in PBLs of control and diabetic mice. (c) Representative FACS staining for CD25 and Foxp3 on gated CD4+ T cells and the percentage of CD4+CD25+Foxp3+ Tregs out of total CD4+ T cells in PBLs of control and diabetic mice (right). Data are shown as mean±s.d. (n=10), for one representative out of three independent experiments. **P<0.01 and ***P<0.001, compared with the identical control mice. FACS, fluorescence-activated cell sorting; PBL, peripheral blood lymphocyte; STZ, streptozotocin; Treg, T regulatory cell.