PDCD1 and neoplasm: To test whether a PD-1 blocking antibody could augment the antitumor activity of an ICOS agonist mAb, we administered EMT6 tumor-bearing mice with the mIgG1 ICOS agonist mAb (7E.17G9) alone and in combination with anti-PD-1 antibody (clone RMP1-14) via intraperitoneal injection.