肿瘤局部存在多种类型的免疫抑制性细胞，其中调节性T细胞 (regulatory T cell，Treg)在肿瘤的发生、发展过程中发挥着极为重要的作用。Treg通过多种机制抑制免疫效应细胞的功能，是肿瘤免疫逃逸的关键因素。这些机制包括分泌抑制性细胞因子抑制效应细胞功能、分泌颗粒酶和穿孔素杀伤效应细胞、干扰效应细胞的代谢功能，以及通过调控树突状细胞影响Treg的分化和增殖，等等。Treg的深入研究为肿瘤免疫治疗提供了新的思路，以Treg及相关免疫抑制性分子作为靶点，通过特异性或非特异性清除Treg、控制Treg的数量和功能等开展肿瘤免疫治疗具有良好的临床应用前景。

There are multiple types of inhibitory immune cells in tumor. Among these cells, Treg (regulatory T cell) plays an extremely important role in tumor development and progression. Treg exihibits potent inhibitory effects on effector cells by a variety of mechanisms, which might be the the key factor for tumor immune escape. These mechanisms include inhibiting the effector cell function by inhibitory cytokines, killing effector cells by granzyme and profrin, interfering effector cell metabolism, and affecting Treg differentiation and proliferation by regulating the function of dendrtic cells, etc. The research on Treg has provided new strategies for tumor immunotherapy. Tumor immunotherapies targeting Treg and related immunosuppressive factors, such as deleting Treg nonsepcificlly or sepcificlly controling the numbers and functions of Treg, might have a bright future in clinical application.

国家重点基础研究发展规划（973计划）资助项目（No.2010CB529901）；卫生部重大传染病防治科技重大专项（No.008ZX10002008）