GNLY+/− mice exhibit enhanced resistance to tumors, numbers of antigen presenting cells, and T cell responses. WT or GNLY+/− mice were injected with CT26 tumor cells in the left flank and the tumor and draining lymph nodes were removed after 12–14 days. A, Weight of excised tumors. Each point represents one animal. B, Tumor infiltrating lymphocytes were stimulated in vitro with PMA/ionomycin and intracellular expression of TNFα and IFNγ measured by flow cytometry. C, GNLY+/− animals have increased numbers of CD40+ and CD86+ cells in the tumor and draining lymph nodes. *p<0.01. Results are representative of 3 similar experiments.