Immunological study for osteoarthritis focusing on T cells.

本研究以T细胞为主要研究对象，探讨了骨关节炎（OA）发病的免疫机制。1）组织学研究表明，OA患者滑膜组织中有CD 3阳性T细胞浸润。SSCP分析证实这些T细胞有克隆性浸润，部分细胞具有TCR Vβ链上的共同CDR 3区（LEFG、VPTGVG、LRGS）。2）骨桥蛋白（OPN）是软骨细胞衍生蛋白之一。骨桥蛋白自身抗体阳性率分别为9.5%和15%。3）软骨相关蛋白YKL-39在大肠杆菌中表达。抗人重组YKL-39（hrYKL-39）自身抗体在OA患者和RA患者中的检出率分别为11.1%和11.8%。在血清对hrYKL-39呈阳性的患者中研究针对hrYKL-39的PBL应答。PBL与hrYKL-39在46%的OA患者中反应，而在RA患者中仅为17%。从表位分析，N-末端片段的三分之一具有最强的抗原性。4）软骨中间层蛋白（CILP），其在老化软骨中分泌，被表达为重组蛋白（hrCILP）。抗hrCILP自身抗体在OA和RA患者中的检出率分别为10.5%和7.9%。CILP蛋白422 ~ 555氨基酸残基片段的抗原性最强。5）软骨细胞与自身PBL共培养时，OA患者PBL的增殖反应是RA患者PBL的5.2倍，这种增殖反应可被抗CD 4、CD 8、HLA I类和HLA II类抗体所抑制。OA滑膜组织中浸润的T细胞具有克隆性，T细胞介导的免疫应答可能参与了OA的发病过程，提示OA的治疗应以T细胞为主。

In this study, we investigated immune mechanism in the pathogenesis in osteoarthritis (OA) focusing on T cell.1) Hitological study showed infiltration of CD3 positive T cells into the synovial tissues from OA patients. Clonal infiltration of these T cells was proven by the SSCP analysis, and some of the cells had shared CDR3 region (LEFG, VPTGVG, LRGS) in TCR Vβ chain.2) Osteopontin (OPN) is one of chondrocyte derived protein. Autoantibody against OPN was detected in 9.5% of sera from OA patients and 15% of rheumatoid arthritis (RA) patients.3) YKL-39, a cartilage-related protein was expressed as a fusion protein using E-coll system. Autoantibody against human recombinant YKL-39 (hrYKL-39) was detected in 11.1% of sera from OA patients and 11.8% of RA patients. PBL response against hrYKL-39 was studied in the patients whose sera was positive for the protein. PBL reacted with hrYKL-39 in 46% of OA patients, it did in only 17 % of RA patients. From the epitope analysis, one third of the N-terminal fragment had strongest antigenicity.4) Cartilage intermediate layer protein (CILP), which is secreted in aged cartilage, was expressed as a recombinant protein (hrCILP). Autoantibldy against hrCILP was detected 10.5% of OA patients and 7.9% of RA patients. The strongest antigenicity was revealed in fragment ranging from 422 to 555 amino residue of CILP protein. Moreover, hrCILP induced chronic arthritis in mice.5) When chondrocytes were co-cultured with self PBL, PBL from OA patients showed higher proliferative response than PBL from RA patients by 5.2 times, This proliferative response was inhibited by anti CD4, CD8, HLA class I and HLA class II antibodies.In conclusion, autoantibody against some proteins derived from cartilage was detected. There was clonality in T cells infiltrating into synovial tissue in OA.Taken together, T cell mediated immune response might be involved in the pathogenesis of OA.The therapeutic strategy focusing T cells was suggested.