TSA-treated CRC tumor cells induce enhanced activation of CD8+ T-cells. SW620 cells were either (A) untreated, (B) irradiated or incubated with (C) 250 uM TSA for 48 hr or as previously described. Tumor cells were subsequently co-cultured with human CEA-specific CD8 + T-cells for 48 hr and the frequency of CD8 + CD25+ T-cells was measured by flow cytometry. T-cell activation was also measured in (D) CD8+ T-cells cultured alone or (E) activated with PMA and ionomycin (P/I) for 24 h. Data were gated first gated on CD8+ population and the percent of CD25+ cells within the CD8+ cell population is shown in (A-E) as histogram plots. (F) a summary graph of results showing percentage of CD8+ T-cells expressing CD25 in both SW620 and HCT116 cells. Experiments were repeated twice with similar results.