Th1 lymphocytes establish solid tumor immunity. (A) Flow cytometric analysis of generated T cells. Cultured cells were stimulated with PMA/ionomycin, stained with surface anti-CD4, and intracellularly with anti–IFN-γ, anti–IL-4, anti–IL-10, or anti–IL-17, respectively, showing the Th1/Th17 phenotype of EpCAM-primed T cells. Representative dot plots are shown. Numbers indicate the percentage of cells in the particular fluorescence window. (B) Short-term cultured Th1 cells protect against CT26-EpCAM tumors. (C) One hundred days after the original tumor challenge, surviving mice received CT26-EpCAM or A20-EpCAM tumor cells or the parental tumors. All mice were protected against a rechallenge with CT26-EpCAM carcinoma cells, and 70% of the mice were protected against A20-EpCAM lymphoma cells, whereas all mice died with the parental A20 lymphoma cells. Mice challenged with parental CT26 cells were largely protected. Experiments were performed as described in “Methods.”