免疫检查点抑制剂是癌症治疗方面的重大突破，然而，仅有少数肝细胞癌（HCC）患者对PD-1抗体治疗呈现积极反应。新抗原是由癌症体内体细胞突变导致序列改变的蛋白质。通过比较整个外显子序列和正常的C57BL / 6小鼠肝脏的序列，本研究鉴定了Hep-55.1C和Dt81 Hepa1-6 HCC的新抗原。具有免疫原性的长肽被合并为肽疫苗。疫苗接种诱导了C57BL / 6小鼠的肿瘤反应性免疫反应，通过IFN-γ ELISPOT和体外杀伤实验的脾细胞证明。在三种小鼠HCC模型治疗中，新抗原疫苗联合PD-1抗体治疗比单独治疗导致更显著的肿瘤缩小。肿瘤浸润淋巴细胞的流式细胞术显示，联合治疗组中Treg细胞和单核髓样抑制细胞减少，CD8+ T细胞增加，疱粒酶B表达增强，CD8+ T细胞上的疲劳相关标记PD-1和Lag-3减少。这些发现为在治疗HCC患者中使用新抗原疫苗联合PD-1抗体进行临床研究提供了强有力的理由。版权所有©2023 Elsevier B.V. 发布。

Immune checkpoint inhibitors are groundbreaking resources for cancer therapy. However, only a few patients with hepatocellular carcinoma (HCC) have shown positive responses to anti-PD-1 therapy. Neoantigens are sequence-altered proteins resulting from somatic mutations in cancer. This study identified the neoantigens of Hep-55.1C and Dt81 Hepa1-6 HCCs by comparing their whole exome sequences with those of a normal C57BL/6 mouse liver. Immunogenic long peptides were pooled as peptide vaccines. The vaccination elicited tumor-reactive immune responses in C57BL/6 mice, as demonstrated by IFN-γ ELISPOT and an in vitro killing assay of splenocytes. In the treatment of three mouse HCC models, combined neoantigen vaccination and anti-PD-1 resulted in more significant tumor regression than monotherapies. Flow cytometry of the tumor-infiltrating lymphocytes showed decreased Treg cells and monocytic myeloid-derived suppressor cells, increased CD8+ T cells, enhanced granzyme B expression, and reduced exhaustion-related markers PD-1 and Lag-3 on CD8+ T cells in the combination group. These findings provide a strong rationale for conducting clinical studies of using neoantigen vaccination in combination with anti-PD-1 to treat patients with HCC.Copyright © 2023. Published by Elsevier B.V.