Oncolytic virus encoding 4-1BBL and IL15 enhances the efficacy of tumor-infiltrating lymphocyte adoptive therapy in HCC.

Previous studies have found that oncolytic virus (OVs) can improve the efficacy of TIL adoptive therapy in oral cancer, colon cancer, and pancreatic cancer. However, the curative effect in hepatocellular carcinoma (HCC) is still unclear. Therefore, this study aims to explore the therapeutic effect and mechanism of OVs encoding 4-1BBL and IL15 (OV-4-1BBL/IL15) combined with TIL adoptive therapy on HCC. In this study, the role and immunological mechanism of armed OVs combined with TILs were evaluated by flow cytometry and ELISA in patient-derived xenograft and syngeneic mouse tumor models. Co-culturing with TILs can up-regulate the expression of antigen-presenting cell (APC) markers on the surface of OV-infected primary HCC cells, and promote the specific activation ability and tumor-killing ability of TILs. OV-4-1BBL/IL15 combined with TIL adoptive therapy could induce tumor volume reduction and anti-tumor immune memory in patient-derived xenograft and syngeneic mouse tumor models. Furthermore, OV combined with TIL adoptive therapy can endow tumor cells with aAPC characteristics, activate T cells at the same time, and reprogram tumor macrophages into anti-tumor phenotype. OV-4-1BBL/IL15 can stimulate the anti-tumor potential of TIL therapy in HCC, and possess broad clinical application prospects.