αDR3-treated T cells are less proliferative and maintain higher Treg frequency. T cells from αDR3 or isotype mAb–treated C57BL/6 mice were plated at 1:1 ratio to γ-irradiated Balb/c splenocytes in an MLR. (A) [3H] Thymidine incorporation of allogeneic responder cells (**P < .01, ***P < .001, ****P < .0001). (B) T cells were stained for FoxP3 before and 96 hours after MLR to assess Tregs (%) of CD4+ T cells (***P < .001). (C-E) Frequencies of TNFα (C), granzyme B (D), and T-bet (E) in CD8+ T cells are shown (*P < .05, ***P < .001). The results of more than 2 independent experiments are shown (N = 4, in total).