Antitumor effect of murine dendritic and tumor cells transduced with IL-2 gene

Interleukin (IL-) 2 acts on a number of types of immune cells promoting their effector functions. To replace systemic administration of recombinant form of this cytokine, various genetically modified cells have been used indifferent preclinical models for tumor growth inhibition. In this study, dendritic or tumor cells transduced with retroviral vector carrying IL-2 gene (JAWS II/IL-2, X63/IL-2, MC38/IL-2 cells) alone or combined with tumor antigen-stimulated dendritic cells (JAWS II/TAg) were exploited to treat colon carcinoma MC38-bearing mice. After the peritumoral injection of vaccine cells, the tumor growth delay and the increase in the number of tumor infiltrating CD4⁺ and CD8⁺ T lymphocytes were noted. A considerable increase in CD4⁺ cell influx into tumor tissue was observed when JAWS II/IL-2 cells or JAWS II/TAg with syngeneic MC38/IL-2 cells were applied. The increase in intensity of CD8⁺ cell infiltration was associated with immune reaction triggered by the same combination of applied cells or JAWS II/TAg with allogeneic X63/IL-2 cells. The effect observed in vivo was accompanied by MC38/0 cell specific cytotoxic activity of spleen cells in vitro. Thus, the application of vaccines, including IL-2-secreting cells of various origins, was able to induce different antitumor responses polarized by exogenous IL-2 and the encountered tumor antigen.