一种新型溶瘤痘苗病毒的抗肿瘤疗效增强，该病毒编码针对 T 细胞免疫球蛋白和 ITIM 结构域（TIGIT）的完全单克隆抗体。

BACKGROUND: Oncolytic virotherapy with vaccinia virus (VV) can lead to effective anti-tumor immunity by turning "cold" tumors into "hot" tumors. However, its therapeutic potential is affected by the tumor's local immunosuppressive tumor microenvironment (TME). Therefore, it is necessary to explore the use of immune checkpoint inhibitors to arm oncolytic VVs to enhance their anti-tumor efficacy. METHODS: A novel recombinant oncolytic VV, VV-α-TIGIT, which encoded a fully monoclonal antibody against T-cell immunoglobulin and ITIM domain (TIGIT) was generated by homologous recombination with a shuttle plasmid. The anti-tumor efficacy of the VV-α-TIGIT was investigated in several subcutaneous and ascites tumor models. FINDINGS: The functional α-TIGIT was sufficiently produced and secreted by tumor cells infected with VV-α-TIGIT, which effectively replicated in tumor cells leading to significant oncolysis. Intratumoral injection of VV-α-TIGIT improved anti-tumor efficacy in several murine subcutaneous tumor models compared to VV-Control (without α-TIGIT insertion). Intraperitoneal injection of VV-α-TIGIT achieved approximately 70% of complete tumor regression in an ascites tumor model. At the same time, treatment with VV-α-TIGIT significantly increased the recruitment and activation of T cells in TME. Moreover, the in vivo anti-tumor activity of VV-α-TIGIT was largely dependent on CD8 T cell-mediated immunity. Finally, the tumor-bearing mice cured of VV-α-TIGIT treatment resisted rechallenge with the same tumor cells, suggesting a long-term persistence of tumor-specific immunological memory. INTERPRETATION: The recombinant oncolytic virus VV-α-TIGIT successfully combines the advantages of oncolytic virotherapy and intratumorally expression of immune checkpoint inhibitor against TIGIT. This novel strategy can provide information on the optimal design of novel antibody-armed oncolytic viruses for cancer immunotherapy. FUNDING: This work was supported by the National Natural Science Foundation of China (81773255, 81472820, and 81700037), the Science and Technology Innovation Foundation of Nanjing University (14913414), and the Natural Science Foundation of Jiangsu Province of China (BK20171098).

背景：溶瘤病毒（VV）的过继免疫治疗可以通过将“冷”肿瘤转变为“热”肿瘤，从而引发有效的抗肿瘤免疫。然而，其治疗潜力受到肿瘤局部免疫抑制肿瘤微环境（TME）的影响。因此，有必要探索使用免疫检查点抑制剂武装溶瘤 VV 以增强其抗肿瘤疗效。

方法：通过同源重组穿梭质粒，生成了一种新型的重组溶瘤 VV（VV-α-TIGIT），该 VV 编码了一种针对 T 细胞免疫球蛋白和 ITIM 结构域（TIGIT）的完全单克隆抗体。在几种皮下和腹水肿瘤模型中，研究了 VV-α-TIGIT 的抗肿瘤疗效。

发现：感染 VV-α-TIGIT 的肿瘤细胞可充分产生和分泌功能性的α-TIGIT，其有效地在肿瘤细胞中复制，导致明显的溶瘤作用。与 VV-Control（未插入α-TIGIT）相比，肿瘤内注射 VV-α-TIGIT 可改善几种小鼠皮下肿瘤模型的抗肿瘤疗效。腹腔内注射 VV-α-TIGIT 可使腹水肿瘤模型中的约 70%的肿瘤完全消退。同时，VV-α-TIGIT 的治疗可显著增加 TME 中 T 细胞的募集和激活。此外，VV-α-TIGIT 的体内抗肿瘤活性在很大程度上依赖于 CD8 T 细胞介导的免疫。最后，经 VV-α-TIGIT 治疗治愈的荷瘤小鼠抵抗了相同肿瘤细胞的再次攻击，提示存在长期的肿瘤特异性免疫记忆。

解释：重组溶瘤病毒 VV-α-TIGIT 成功地结合了溶瘤病毒治疗和肿瘤内表达针对 TIGIT 的免疫检查点抑制剂的优势。这种新策略可以为癌症免疫治疗提供有关新型抗体武装溶瘤病毒的最佳设计信息。

资金：本工作得到了国家自然科学基金（81773255、81472820 和 81700037）、南京大学科技创新基金（14913414）和江苏省自然科学基金（BK20171098）的资助。