Mice injected with ID8/GFP tumor cells received three doses of chNKG2D T cells 5, 7, and 9 weeks post-tumor inoculation, and these mice became long-term tumor-free survivors. (a) Tumor-surviving mice were re-challenged with 2 × 106 ID8/GFP-shRae1 cells i.p. 250 days after ID8/GFP injection. After 8 weeks, the number of solid tumors and tumor cells in ascites were assessed (***, p < 0.001 vs. naïve). (b) Splenocytes from tumor-surviving mice who did not receive a tumor re-challenge were isolated (at 250 days) and tested for production of IFN-γ in response to ID8, ID8/GFP-shRae1, RMA, and RMA-Rae1 (RMA-R) cells (***, p < 0.001 vs. naïve).