Efficient tumor suppression by glioma-specific murine cytotoxic T lymphocytes transfected with interferon-gamma gene.

We have recently shown that exogenous expression of the mouse interferon-gamma (IFN-gamma) gene augmented the cell-killing potential of a line of cytotoxic T lymphocytes (CTLs) specific against a murine glioma line (203-glioma). In the present work, we further investigated the in vivo antitumor effects of the E gamma-6 and E gamma-9 sublines of this CTL line transfected with the IFN-gamma gene. Using the Winn assay to test the neutralization of subcutaneous gliomas, we determined that these CTL sublines were more effective than the E-4 parent CTL line and that suppression of the tumor growth was dependent on the number of effector cells (CTLs). Moreover, intravenous injection of E gamma-9 cells was more effective in suppressing the tumor growth than intravenous injection of E-4 cells. These results suggest that transfection of antitumor effector cells with the IFN-gamma gene could improve the efficacy of adoptive immunotherapy against cancer.