肝癌干细胞被认为是肝癌治疗后复发和转移的一个重要根源。我们前期研究发现ANXA3抗原特异性CTLs能靶向杀伤肝癌干细胞，抑制小鼠肝癌生长，但治疗后的小鼠肝癌组织仍残存肝癌干细胞，这可能与肿瘤细胞通过PD-1/PD-L1轴抑制CTLs抗肿瘤作用有关。而目前有关肝癌干细胞免疫逃逸的机制，以及抗PD-1抗体对ANXA3抗原特异性CTLs抗肝癌作用的影响及其机制尚不清楚。本项目拟继续研究肝癌干细胞的免疫抑制作用及其对ANXA3抗原特异性CTLs免疫功能的影响；探索ANXA3抗原特异性CTLs抗肝癌作用最强时所需的最低抗PD-1抗体剂量，并分析其对CTLs迁移能力的影响和机制；最后用动物模型分析低剂量抗PD-1抗体对ANXA3抗原特异性CTLs瘤内迁移浸润和免疫微环境的影响，以期阐明低剂量抗PD-1抗体增强ANXA3抗原特异性CTLs抗肝癌作用的机制，为将来开展肝癌新的免疫治疗方法提供理论依据。

Hepatocllular carcinoma cancer stem-like cells (HCC CSCs) might be the source of tumor relapse and metastasis. In the previous work we demonstrated that ANXA3 antigen specific CTLs could preferentially kill HCC CSCs and inhibit tumor growth in nude mice. However, HCC CSCs survived in the residual disease after CTLs treatment, which might be correlated with the CTLs function inhibition by the tumor cells via PD-1/PD-L1 axis. Besides, the mechnism of HCC CSCs immune escaping and the role of anti-PD-1 antibody in the anti-tumor action of ANXA3 antigen specific CTLs for HCC remains unkown. In this project, we investigate the immune suppression of HCC CSCs and its effect on ANXA3 antigen specific CTLs by immunochemistry and flow cytometry. Moreover, The optimal dose of anti-PD-1 antibody will be explored, and the role of low dose anti-PD-1 antibody in the anti-tumor action and infiltration ability of ANXA3 antigen specific CTLs for HCC will be evaluated as well by multiple approaches, inculding co-culture assasys, protein chip, lentivirus mediated gene delivery and immunocompetent mouse experiments, thus, elucidating the mechnism how low dose anti-PD-1 enhance the anti-tumor action of ANXA3 antigen specific CTLs and providing novel clues and therapeutic strategies for HCC patients.