IL2 and Autoimmunity: For this, we first generated bone marrow (BM) chimera reconstituted with a 50:50 ratio of WT and IL-2−/− BM cells to avoid spontaneous T cell activation due to autoimmunity in IL-2−/− mice (37) and 8 weeks later, naïve CD4+ T cells derived from WT and IL-2−/− BM were isolated from the chimeric mice (Figure S6C).