CD8 Tregs inhibit cytokine production from naive and effector CD4 and CD8 T cells. (A) OT-2 cells were stimulated with OVA257, OVA323, or both, with or without addition of OT-1 Tc1 cells or Tregs (generated as in Figure 1) at a ratio of 1 Tc1/Treg to 2 OT-2 CD4 cells. After 24 hours, IL-2 secretion was measured by ELISA. (B) CD8 Tregs inhibit cytokine production of Th1 and Th2 effectors. OT-2 Th1 or Th2 effector cells were restimulated for 5 hours with DCs + OVA257 + OVA323 + monensin, with or without OT-1 Tc1 cells or Tregs at a 1:1 ratio. The percentage of IL-4 and IFN-γ–producing cells in gated OT-2 targets are shown. (C) CD8 Tregs inhibit cytokine production of Tc1 CD8 effectors. OT-1 Tc1 effector cells were restimulated for 5 hours with DCs ± OVA257 + monensin, ± CFSE-labeled OT-1 Tregs (1:1). IFN-γ staining in CFSE-negative Tc1 targets is shown. All data are representative of 3 independent experiments with similar results.
