Blockade of both MHC I and MHC II eliminated all antitumor effects imparted by CD8 T cells and converted Treg cells (Supplementary Fig. 15, Supplementary Fig. 16), suggesting that direct TCR-MHC interaction is required for antitumor effects and that both arms of the T cell response jointly contribute to tumor killing. The gene discussed is CD8A; the disease is neoplasm.