Redirected perforin-dependent lysis of colon carcinoma by ex vivo genetically engineered CTL

The redirection of autologous lymphocytes to predefined tumor target Ags ha s considerable potential for the immunotherapeutic treatment of cancer; how ever, robust experimental systems for comparing various approaches have not been developed. Herein, we have generated a single chain variable domain a nti-carcinoembryonic Ag (CEA) Fc epsilon receptor I gamma-chain fusion (scF v anti-CEA) receptor and demonstrated high-level expression of this chimeri c receptor in naive mouse T lymphocytes by retroviral gene transduction. Th ese gene-modified CTL were able to lyse CEA(+) targets and secrete high lev els of IFN-gamma following Ag stimulation. Depletion studies demonstrated t hat specific tumor cell cytotoxicity was mediated by gene-modified CD8(+) T cells. Importantly, in increasingly stringent tests of efficacy in vivo, t ransduced CTL were sequentially shown to reject CEA(+) colon carcinoma cell s in a Winn assay and then reject established s.c. colon carcinoma in scid or syngeneic mice. Furthermore, using gene-targeted and scFv anti-CEA recep tor-transduced donor CTL, perforin and IFN-gamma were demonstrated to be ab solutely critical for the eradication of colon carcinoma in mice. In summar y, we have developed a highly efficient gene transfer system for evaluating chimeric receptor expression in cytotoxic lymphocytes. This series of expe riments has revealed the utility of scFv anti-CEA chimeras in providing mou se T cells the capacity to reject colon carcinoma in an Ag- and perforin-sp ecific manner.