Generation and Targeting of Human Tumor-Specific Tc1 and Th1 Cells Transduced with a Lentivirus Containing a Chimeric Immunoglobulin T-Cell Receptor

CD4⁺ Th cells, in particular IFN-γ-producing Th1 cells, play a critical role in the activation and maintenance of Tc1 cells that are essential for tumor eradication. Here, we report the generation of artificial tumor-specific Th1 and Tc1 cells from nonspecifically activated T cells using a lentiviral transduction system. Anti-CD3-activated T cells from healthy human donors were transduced with a lentivirus containing a chimeric immunoglobulin T-cell receptor gene composed of single-chain variable fragments derived from an anticarcinoembryonic antigen (CEA)-specific monoclonal antibody fused to an intracellular signaling domain derived from the cytoplasmic portions of membrane-bound CD28 and CD3ζ. These artificial tumor-specific Tc1 and Th1 cells, termed Tc1- and Th1-T bodies, respectively, could be targeted to CEA ⁺ tumor cells independently of MHC restriction. Specifically, Tc1-T bodies demonstrated high cytotoxicity and produced IFN-γ in response to CEA⁺ tumor cell lines but not CEA⁺ tumors. Although Th1-T bodies exhibited low cytotoxicity, they secreted high levels of IFN-γ and interleukin-2 in response to CEA⁺ tumor cells. Such CEA⁺ tumor-specific activation was not observed in mock gene-transduced nonspecific Tc1 and Th1 cells. Moreover, Tc1- and Th1-T bodies exhibited strong antitumor activities against CEA⁺ human lung cancer cells implanted into RAG2^-/- mice. Furthermore, combined therapy with Tc1- and Th1-T bodies resulted in enhanced antitumor activities in vivo. Taken together, our findings demonstrate that Tc1- and Th1-T bodies represent a promising alternative to current methods for the development of effective adoptive immunotherapies.