The transcription factor Tbet (Tbx21 gene) drives IFN γ-associated type 1 responses and Tbet deficiency in Treg cells results in defective immune control in models of infection and autoimmunity, particularly through the loss of IFNγ as well as many properties of Treg cells, including their proliferation, maintenance, and suppressive activity9,18–21. Here, TBX21 is linked to infection.