携带HLA-G外泌体与肿瘤免疫

Exosomes bearing HLA-G and tumor immunology

人类白细胞抗原G（human leukocyte antigen G，HLA-G）属于非经典HLA I类分子，是机体内一种重要的免疫耐受分子。其表现形式多样化，初始转录产物经选择性剪接后可产生膜结合型与可溶型两种形式。HLA-G可通过多种途径促进肿瘤细胞侵袭与转移。外泌体是由绝大多数细胞释放的具有脂质双分子层和丰富内容物的纳米级微囊泡结构，作为一种全新的疾病标志物，广泛参与疾病发生及发展。最近研究发现，外泌体上表达可溶性HLA-G。外泌体上HLA-G的发现揭示了HLA-G发挥免疫抑制作用，调节肿瘤微环境的另一种途径。本文就携带HLA-G外泌体在肿瘤免疫中的进展作一综述，为肿瘤早期发现与治疗提供新思路。

Human leukocyte antigen G （HLA-G） is a member of the non-classical HLA class Ⅰb family. It is considered to play a crucial role in immune tolerance. A unique feature of HLA-G is the structural diversity as surface expressed and as secreted molecules, which is mainly attributed to alternative splicing of the primary transcript. HLA-G can promote the invasion and metastasis of tumor cells through various ways. In addition, HLA-G has been described included in exosomes. Exosomes released by most cell types are nano-sized vesicular bodies that contain lipid bilayer and rich contents. As a new marker for diseases, exosomes are extensively involved in the occurrence and development of diseases. Recent studies have found that exosomes can express soluble HLA-G, which reveal a new way by which HLA-G regulates tumor microenvironment. In this review, we focus on the expression of HLA-G on exosomes to provide new thoughts for the early detection and treatment of tumors.