When T cells and Treg cells were co-transferred together into mice (a situation where Itgb8 KO Treg cells completely prevented colitis [Figures S3A–S3D]), pSmad2/3 in transferred T cells was equivalent in the presence of both control or Itgb8 KO Treg cells 6 weeks after transfer (Figure S4K), indicating that during Treg-cell-mediated prevention of colitis, TGF-β signaling in T cells does not require integrin β8 expression on Treg cells. Here, TGFB1 is linked to colitis.