封闭CD25和中和TGF-β下调胰腺癌微环境中Treg及增强新型MUC1 DNA疫苗治疗效果的研究

胰腺癌预后极差，肿瘤疫苗有望改善预后。肿瘤微环境中调节性T细胞（Treg）抑制效应T细胞的杀伤功能，从而限制疫苗的治疗效果。我们前期研究证实，CD25和TGF-β分别是胰腺癌微环境中Treg分化、功能维持的关键表型和关键细胞因子。提示以此为联合干预靶点，有望从数量上和功能上阻断胰腺癌微环境中Treg抑制CTL杀伤功能的途径，从而增强疫苗的治疗效果。目前我们已成功构建了表达MUC1的小鼠胰腺癌模型和新型MUC1 DNA疫苗，本项目拟完成：①研究腹腔注射抗CD25单抗和抗TGF-β单抗对胰腺癌微环境中Treg的下调作用；②探讨封闭CD25和中和TGF-β对新型疫苗治疗胰腺癌效果的影响；③通过体外杀伤实验，分析CTL杀伤功能的影响因素。通过上述研究，力图阐明封闭CD25和中和TGF-β下调胰腺癌微环境中Treg对新型MUC1 DNA疫苗治疗效果的影响和作用机制，最终为肿瘤疫苗的临床应用奠定基础。

The prognosis is extremely poor, and is hopeful to be improved by tumor vaccine. Regulatory T cells (Treg) in tumor microenvironment might limit therapeutic efficacy of tumor vaccine through suppressing killing ability of effector T cells. In our previous research, it is proved that CD25 and TGF-β is respectively the key phenotypic marker and the critical cytokine in the differentiation and function of Treg. Therefore, it is suggested that CD25 and TGF-β would be potential combined intervention points to downregulate Tregs amount and function of suppressing CTL killing ability in pancreatic cancer microenvironment, and then to enhance therapeutic vaccine efficacy. At present, we have successfully established C57BL/6 murine model of pancreatic tumor expressing MUC1 and constructed new MUC1 DNA vaccine. In this study, anti-CD25 monoclonal antibody and anti-TGF-βmonoclonal antibody will be injected intraperitoneally to block CD25 and neutralize TGF-β respectively. Firstly, the pole on reduction and functionally depletion of Tregs in pancreatic cancer microenvironment will be explored. Secondly, we will investigate the effect of blocking CD25 and neutralizing TGF-β on murine pancreatic cancer treatment with new MUC1 vaccine. Finally, we analyze the influencing factor of CTL killing ability through cell experiment in Vitro. By means of above studies, the influence and mechanism will be elucidated and then lay a foundation of further clinical use of tumor vaccine, where blocking CD25 and neutralizing TGF-β could result in downregulating regulatory T cells in pancreatic cancer microenvironment and enhancing therapeutic efficacy of new MUC1 DNA vaccine.