Anti- Esophageal Cancer Active Immunity Induced by FasL/B7-1 Genes Modified Tumor Cells

To study the activation of CTLs against esophageal cancer cells induced by FasL/B7-1 (FB-11)genes modified tumor cells, and to explore whether co-expression of FasL and B7-1 in Eca-109 tumor cells could initiate an synergistic antitumor effect. FasL and B7-1 genes were transfected into human Eca-109 Eca-109 cancer cells with adenovirus vectors. The positive clones were selected by G418. FasL and B7-1 were detected by Flow cytometry and RT-PCR . The abdominal infiltrating lymphocytes and sensitized spleen cells were obtained from the mice who were immunized with Eca-109/FB-11 or wild type Eca-109 cells intraperitoneally, and the cytotoxicity of these CTLs against tumor cells was determined by MTT assay. Flow cytometry and RT-PCR showed that FasL and B7-1 were highly expressed. FasL⁺/B7-1⁺ Eca-109 cells (Eca-109/FB-11) were inoculated subcutaneously in the dorsal skin of C57BL/6 mice and then they decreased their tumorigenicity greatly (z=2.15-46.10, p<0.01). The Eca-109/FB-11 cell-sensitized mice obtained the protective immune activity against the rechallenge of wild type Eca-109 cells (z=2.06-44.30, p<0.05). It was showed that the cytotoxicity of CTLs induced by Eca-109/FB-11 cells against Eca-109 was significantly higher than that of CTLs activated by wild-type Eca-109 cells (84.1plusmn2.4% vs 30.5plusmn2.3%, p<0.05). The results suggest that the FasL and B7-1 can effectively promote the activity of CTLs against esophageal cancer cells.