T cells from nontolerized wt or CCR9−/− mice were adoptively transferred into CCR9−/− recipients. OT and DTH were induced as described in Fig. 1. CCR9−/− mice receiving CD4+ T cells from DEREG mice were treated with DT every day. (A, E) DTH responses were measured after 24 hours (n=2–5 mice/group). (B–D, F) Total splenocytes were stimulated with the indicated OVA concentrations. (B, D, F) Proliferation was assessed after 72 hours (n=4–5 mice/group). (C) IL-10 was measured in the culture supernatant after 48–60 hours. Mean ± SEM, *p<0.05, ***p<0.001