Abstract: BACKGROUND ＆ AIM: To study the cytotoxic activity of CTL and cytokines production of lymphocytes induced by 4-1BBL-transfected colon26 in vitro. MATERIALS AND METHODS: The eukaryotic expression vector pMKITneo/4-1BBL was transfected into colon26 by lipofectamine2000, then the cells with high expression of 4-1BBL were selected by G418. The tumor cell vaccines (TCV) were obtained by treatment with mitomycin(MMC).The TCV were co-cultivated with syngeneic murine cytotoxic T lymphocytes (CTL).Then the cytotoxic activity of CTL and the cytokines production of spleen cells were tested. RESULTS: The colon26 cells transfected with 4-1BBL showed strong expression of 4-1BBL protein on cell surface. Compared with TCV-colon26,the TCV-colon26/4-1BBL cells could induce a more efficient cytotoxic activity of CTL against its parental tumor cell colon26(P<0.01),but not against non-parental tumor cell S180.The TCV-colon26/4-1BBL could significantly enhance the ability of murine spleen cells to produce cytokines(P<0.01). CONCLUSION: The murine colon26 tumor cells transfected with 4-1BBL could induce an efficient anti-tumor immune response.

Key words: 4-1BB ligand, cytotoxic T lymphocyte, cytokine, tumor vaccines