VTCN1 and neoplasm: To determine if the effects of B7x on Treg populations is consistent in multiple tumor models, we repeated these studies in the Hepa1-6 and CT26 tumor models as well (Supplementary Fig. 1a–g), and consistently observed increased Treg infiltration in B7x+ tumors as compared to their B7x- counterparts, as well as increased Treg: CD8 ratios (Supplementary Fig. 1c, f).