MICA 脱落与肿瘤免疫逃逸：肿瘤免疫治疗新靶标和新策略

MHC Ⅰ类链相关分子（MICA）是自然杀伤细胞和T 细胞上NKG2D 受体的主要活化性配体，在上皮源性肿瘤细胞表面过表达。NKG2D 与MICA 的结合可有效刺激效应细胞对肿瘤细胞的细胞毒作用。然而，临床观察表明，MICA 会在肿瘤的增殖过程中脱落而形成可溶性MICA（sMICA），这被认为是肿瘤细胞逃脱NKG2D 介导的免疫监视的重要原因。综述在肿瘤细胞中MICA 和NKG2D 的表达与功能、sMICA 的形成与肿瘤免疫逃逸的关联以及介导MICA 脱落的机制，由此探讨肿瘤免疫治疗的新靶点和新策略。

MICA Shedding and Tumor Immune Escape: the Novel Target and Novel Strategy for Tumor Immunotherapy

MHC class I chain-related molecule A(MICA) is one of the major activating ligands of NKG2D(natural killer group 2, member D) receptor on natural killer (NK) cells and T cells., which is overexpressed on the surface of tumor cells of epithelial origin. The cytotoxic effect of the effector cells on tumor cells could be mediated by the interaction of MICA with NKG2D. However, clinical researches have suggested that MICA will shed foming soluble MICA (sMICA) during the process of tumor proliferation, which is recognized as the major reason for tumor to escape NKG2Dmediated immunosurveillance. The expressions and functions of MICA and NKG2D, the association of the formation of sMICA with tumor immune escape and the mechanism of MICA shedding in tumor cells were reviewed, discussing the novel target and novel strategy for tumor immunotherapy .