MHC Ⅰ类分子是启动机体免疫应答的重要分子。当细胞遭受病毒感染或本身发生癌变,MHCⅠ类分子能结合病毒或癌变细胞蛋白降解形成的多肽,向CD8+T细胞报告病毒或者肿瘤的存在,从而促使其对异常细胞的杀伤。在此过程中,MHCⅠ类分子的胞内转运途径精密调控着免疫应答的效率,但目前对MHCⅠ类分子在胞内转运途径的机制了解不多。本综述就MHCⅠ类分子在内质网的组装、外运以及内吞后降解或再循环过程中的主要机制做一阐述,并且介绍一些新发现的相关调控分子。 MHC class I molecules are important molecules that initiate the immune response in the body. When a cell suffers from a viral infection or itself becomes cancerous, MHC class I molecules can bind to the polypeptide formed by the degradation of a virus or cancerous cell protein and report the presence of a virus or tumor to CD8 + T cells, thereby promoting their killing of abnormal cells. During this process, the intracellular transport of MHC class I molecules precisely regulates the efficiency of the immune response, but little is known about the mechanism of intracellular transport of MHC class I molecules. This review summarizes the major mechanisms by which MHC class I molecules are assembled, transported, and degraded or recycled after endocytosis in the endoplasmic reticulum (ER), and introduces some newly discovered regulatory molecules.