An effective vaccine against colon cancer in mice: Use of recombinant adenovirus interleukin-12 transduced dendritic cells

Figure 5 Assays for IFNγ secretion and tumor-specific CTL activity in the immunized mice. Splenic CD3⁺ T cells from mice that survived the CT26 tumor challenge until d 61 in protective models were magnetically isolated. CD3⁺ T cells were restimulated ex vivo by culturing with the MMC-treated CT26 tumor cells. Then these restimulated effector T cells were added to the wells containing target CT26 or SGC-7901 tumor cells in 96-well plates. After 20 h, supernatant from each well was collected for measuring IFNγ production with the mouse IFNγ ELISA kit (A), and for measuring cytolytic activity with a Cytotoxicity Detection Kit (B). In some experiments, the target CT26 tumor cells were incubated with a MAb to MHC classImolecules (anti-H2Db/H2Kb) or with control antibody (anti-H2Dd) before the addition of restimulated effector T cells to evaluate the specificity of CTL activity. Statistical analysis used the paired Student’s t test. Data are given as mean ± SE. A, B ^aP < 0.05, CT26 TP AdVIL-12/DCs compared with CT26 TP DCs in the CT26 groups, ^bP < 0.01 CT26 vs SGC7901 or Non, respectively. (C), ^aP < 0.05, CT26 + antiH-2kb/DbmAb vs CT26 or CT26 + antiH-2DbmAb, respectively.