Single chain Ig/γ gene-redirected human T lymphocytes produce cytokines, specifically lyse tumor cells, and recycle lytic capacity

To enable construction of CTL with known predefined Ab specificity for adoptive immunotherapy, we constructed a chimeric scFv/gamma gene composed of the variable regions of a mAb joined to the Fc(epsilon)RI signaling receptor gamma-chain of mast cells. Introduction of this chimeric receptor into CTL rendered these lymphocytes specific for renal cell carcinoma. This approach combines the specificity of tumor-selective Abs with the efficacy of CTL to destroy tumor cells. We not only demonstrated that the transduced CTL functionally express the scFv/gamma receptor for a prolonged period of time (4.5 mo of in vitro culture), but also showed high levels of Ab-dictated lysis of renal cell carcinoma similar to that of normal CTL, and importantly, we demonstrated that these CTL can recycle their lytic activity. Moreover, these scFv/gamma-expressing T lymphocytes produce cytokines upon stimulation with the relevant target cell. These results together with the donor independence of our gene transduction protocol demonstrate the feasibility of redirecting T lymphocytes for cancer treatment.