Antitumor Activity of Lentivirus-mediated Interleukin -12 Gene Modified Dendritic Cells in Human Lung Cancer in Vitro

Objectives: Dendritic cell (DC)-based tumor immunotherapy needs an immunogenic tumor associatedantigen (TAA) and an effective approach for its presentation to lymphocytes. In this study we explored whethertransduction of DCs with lentiviruses (LVs) expressing the human interleukin-12 gene could stimulate antigenspecificcytotoxic T cells (CTLs) against human lung cancer cells in vitro. Methods: Peripheral blood monocytederivedDCs were transduced with a lentiviral vector encoding human IL-12 gene (LV-12). The anticipated targetof the human IL-12 gene was detected by RT-PCR. The concentration of IL-12 in the culture supernatant of DCswas measured by ELISA.Transduction efficiencies and CD83 phenotypes of DCs were assessed by flow cytometry.DCs were pulsed with tumor antigen of lung cancer cells (DC+Ag) and transduced with LV-12 (DC-LV-12+Ag).Stimulation of T lymphocyte proliferation by DCs and activation of cytotoxic T-lymphocytes (CTL) stimulatedby LV-12 transduced DCs pulsed with tumor antigen against A549 lung cancer cells were assessed with methylthiazolyltetrazolium (MTT). Results: A recombinant lentivirus expressing the IL-12 gene was successfullyconstructed. DC transduced with LV-12 produced higher levels of IL-12 and expressed higher levels of CD83than non-transduced. The DC modified by interleukin -12 gene and pulsed with tumor antigen demonstratedgood stimulation of lymphocyte proliferation, induction of antigen-specific cytotoxic T lymphocytes and antitumoreffects. Conclusions: Dendritic cells transduced with a lentivirus-mediated interleukin-12 gene have anenhanced ability to kill lung cancer cells through promoting T lymphocyte proliferation and cytotoxicity.