HLA-DR4结合性瓜氨酸化α-烯醇化酶多肽在类风湿关节炎发病中的作用研究

The central pathogenisis of rheumatoid arthritis (RA) is that antigen peptides specifically bind with HLA-DR4, and activate T cell response. Citrullination of antigens are strongly associated with the onset of RA. α-enolase from Pg germ is citrullinated by its own PAD and then trigger the auto-immune responses towards human citrullinated α-enolase and other antigens by molecular mimicry and epitope spreading. Citrullinated α-enolase is an important pathogenic antigen in RA. In this study, HLA-DR4 binding citrullinated α-enolase peptides (CEP) are identified, their HLA-DR4 binding capacity is analyzed. The impact on proliferation and differentiation of T cells, effect on experimental arthritis models of CEP derived from human and Pg are explored. The study provide new evidence for the pathogenisis of citrullinated antigen and the theory of pathogen in RA, and further provide the new target for early RA diagnosis and immunotherapy.

抗原肽与HLA-DR4分子特异性结合，进而激活T细胞是类风湿关节炎（RA）发病的核心环节。抗原瓜氨酸化与RA的发病密切相关。牙龈卟啉单胞菌（Pg）的α-烯醇化酶（α-enolase）可被自身PAD酶瓜氨酸化，通过分子模拟和表位扩展机制诱发RA患者针对人α-enolase等一系列瓜氨酸化抗原的自身免疫反应，是RA免疫损伤的主要致病分子。本项目利用HLA-DR4转基因鼠，筛选和鉴定α-enolase中与HLA-DR4特异性结合的瓜氨酸化抗原多肽（CEP），从分子、细胞、转基因动物及RA患者外周血和滑液等不同层面，分析人和Pg均来源的CEP多肽与HLA-DR4的结合能力、对T细胞亚型活化和分化的影响，以及对实验性关节炎发生发展的作用，为瓜氨酸化抗原在RA的致病机制及感染参与RA发病的理论提供新的实验依据，为RA早期诊断和治疗寻找新的靶点。

抗原肽与HLA-DR4分子特异性结合，进而激活T细胞是类风湿关节炎（RA）发病的核心环节。抗原瓜氨酸化与RA的发病密切相关。口腔细菌产生的α-烯醇化酶（α-enolase）可被自身PAD酶瓜氨酸化，通过分子模拟和表位扩展机制诱发RA患者针对人α-enolase等一系列瓜氨酸化抗原的自身免疫反应，是RA免疫损伤的主要致病分子，可能参与RA发病的初始环节。本项目鉴定得到了α-enolase中与RA患者易感HLA-DRB1特异性结合的瓜氨酸化抗原多肽（CEP-1），证实了CEP-1多肽与RA易感HLA-DRB1共同表位密切相关，能够诱导产IL-17和IFN-r的自身反应性T细胞亚型，参与T细胞的功能及分化调节。抗CEP-1抗体可见于64.3%的RA患者，其对RA诊断的敏感性和特异性分别为64.3%、94.5%。抗CEP-1抗体阳性患者关节损害重，且疾病活动度高。抗CEP-1抗体是RA患者肺间质病变的独立危险因素。本项目为瓜氨酸化抗原在RA的致病机制及感染参与RA发病的理论提供新的实验依据，为RA早期诊断和治疗提供了新的靶点。