As shown in Fig. 1B , IL-12 but not IL-6 or IFN-c induced IFNc production by Tregs and Tconvs although IL-12 induced lower levels of IFN-c in Tregs than in Tconvs. After 42 hours, the majority of Tconv and Tregs expressed IFN-c; by 66 hrs nearly all of the cells were IFN-c + (Fig. 1C) . Further, IL-12 treatment increased proliferation of Tconvs (Fig. 1B, D) and CD8 T cells (data not shown), but, in contrast, diminished frequency and proliferation of Tregs (Fig. 1A, D, E) . IL-12 also decreased levels of Foxp3 in Tregs (Fig. 1F ). The net result was a decreased proportion of Tregs expressing reduced levels of Foxp3 in IL-12treated cell cultures (Fig. 1A, E) . IL-6 reduced both Tconv and Treg proliferation although the effects on Treg proliferation were greater (Fig. 1B, D) .