The phenotype of CD4+CD25+ Tregs was altered in mice with STZ-induced diabetes for 4 months. Splenocytes from control and diabetic mice were collected 4 months after the onset of diabetes and stained for CD4, CD25 and other surface markers including CD62L, CD45RB, CD44 and GITR. Intracellular staining of CTLA-4 and Foxp3 was performed after the staining of the surface markers. (a) One representative FACS stain for each of the indicated molecules gated on CD4+CD25+ T cells. The open histograms represent staining of cells from the control mice, while the black filled histograms represent staining of cells from the diabetic mice. (b) The percentages of CD62L+, CD44+, CD45RB+, GITR+ or Foxp3+ cells out of total CD4+CD25+ T cells in control and diabetic mice. Data are shown as mean±s.d. (n=8), for one representative out of two independent experiments. *P<0.05, **P<0.01 and ***P<0.001, compared with the control mice. CTLA-4, cytotoxic T lymphocyte-associated antigen 4; FACS, fluorescence-activated cell sorting; GITR, glucocorticoid-induced tumor-necrosis factor receptor; STZ, streptozotocin; Treg, T regulatory cell.