Molecular Mechanism in Sjogren's syndrome

对干燥综合征（SS）患者唇唾液腺T细胞上的T细胞受体（TCR）的分析支持浸润T细胞由抗原驱动而不是超抗原驱动刺激诱导的观点。采用T细胞系、PCR-SSCP、West-Western和TOP a/B转染等方法，对SS患者唇腺浸润T细胞识别的T细胞表位进行了研究。1)通过对唇腺T细胞系的细胞增殖分析，发现Ro/SS-A蛋白的AA 203 -21 - 2位为T细胞表位（DEREQLRILG）。2)经SSCP分析和合成肽库分析表明，WAEILRIGRV（TORBV 6S 7）和WVNMLRRGI（HSP 10/60）是合适的候选抗原。WAEILRIGRV（TOPBV 6S 7）反应性T细胞在体外可产生IL-2和IL-4，而WVNMLRRGI（HSP 10/60）反应性T细胞仅能产生IL-2。3)使用来自唾液腺中独特TOP的TOR CDR 3蛋白的West-Western分析阐明了人α-淀粉酶唾液前体（NPFRPWWERYQWPV，AA 68 -80和EKMSYLKNWGEG，AA 287 -298）是SS中唾液腺特异性自身抗原的候选者。事实上，11名SS患者中的3名（27%）在唇唾液腺中显示α-淀粉酶反应性T细胞。4)从SS患者唇腺单个T细胞中分离到一对TOP a和B链的全长cDNA。结论：α-淀粉酶是唾液腺特异性自身抗原，Ro/SS-A 52 kD和HSP 10/60是唾液腺非特异性自身抗原。此外，尽管TCRBV 6S 7可能是SS的调节性T细胞表位，但一些自身抗原如Ro/SS-A 52 kD和HSP 10/60被认为是SS发生中的自身攻击性T细胞表位。

Analyses of T cell receptor (TCR) on T cells in labial salivary glands of patients with Sjogren's syndrome (SS) support the notion that infiltrating T cells were induced by antigen-driven rather than superantigen-driven stimulation. T cell epitopes recognized by T cells infiltrating in the labial salivary glands of SS patients have been clarified using different four strategies such as T cell lines, PCR-SSCP, West-Western, and TOP a/b transfectants methods. 1) Cell proliferative analysis by T cell lines from labial salivary glands showed T cell epitope (DEREQLRILG) at position AA203-21 2 of Ro/SS-A protein. 2) Analysis with SSCP and the synthetic peptides combinatorial libraries demonstrated that WAEILRIGRV (TORBV6S7) and WVNMLRRGI (HSP10/60) were suitable candidates for antigens. WAEILRIGRV (TOPBV6S7) reactive T cells could produce both IL-2 and IL-4, while WVNMLRRGI (HSP10/60) reactive T cells were able to produce only IL-2 in vitro. 3) West-Western analysis using TOR CDR3 protein from unique TOP in salivary glands clarified that human a-amylase salivary precursor (NPFRPWWERYQWPV, AA68-80 and EKMSYLKNWGEG, AA287-298) is a candidate for salivary glands-specific autoantigens in SS.In fact, 3 of 11 SS patients (27%) showed a-amylase reactive T cells in labial salivary glands. 4) A full-length cDNA encoding paired TOP a and b chains has been isolated from a single T cell in labial salivary glands of SS patient. In conclusion, a-amylase function as salivary glands-specific autoantigen, whereas Ro/SS-A 52kD, and HSP10/60 act as glands-non-specific autoantigens. Furthermore, some autoantigens such as Ro/SS-A 52kD and HSP1 0/60 are thought to be autoaggressive T cell epitopes in the generation of SS, although TCRBV6S7 might be aregulatory T cell epitope in SS.