Identification of a specific autoantigen in opticospinal form of multiple sclerosis based on the HLA-DPB1 binding motif

多发性硬化症(MS)目前被认为是由抗髓鞘抗原的自身反应性T细胞介导的。在日本，多发性硬化症经常和选择性地影响视神经和脊髓。我们以前报道过，视神经脊髓型多发性硬化症(OS-MS)在临床、免疫学和免疫学上都有别于传统的多发性硬化症(C-MS)。近年来，少突胶质细胞被证实具有多个来源，不同来源的少突胶质细胞在分布上有显著差异。我们推测，存在于视神经和脊髓中的特异性自身抗原可能与OS-MS病变的发生有关。为了鉴定OS-MS中的自身抗原，我们利用来自OS-MS患者的血清样本对人脊髓表达文库进行了免疫筛选。从人脊髓制备表达文库，用8个OS-…的血清免疫筛选5×10~5~10×10~5噬菌斑更多多发性硬化症患者。通过对血清的反应性鉴定了11个免疫阳性克隆，并对它们的序列进行了分析。序列比较表明，这些克隆代表了5个不同基因(HSP105、Rabaptin-5、NSD1、KIAA1640、KIAA0640)的cDNA。制备GST-Rabaptin-5融合蛋白和HSP105蛋白，用ELISA法检测血清和脑脊液中抗Rabaptin-5和HSP105自身抗体的效价。我们发现抗Rabaptin-5的Ig G反应无明显升高，但MS患者的Ig G抗HSP105反应明显高于正常对照组(p=0.0193)。抗HSP105抗体阳性率为14.5%(10/69)，对照组为3%(2/66)。OS-MS和C-MS之间自身抗体的患病率差异无统计学意义。从9例MS患者中有3例建立了来源于α~+CD45RO~+T细胞的HSP105CD45RO~+反应性T细胞系。我们的研究结果表明，HSP105是一种新的MS候选自身抗原，今后我们将对其他候选自身抗原(NSD1、KIAA1640、KIAA0610)进行分析。较少

Multiple sclerosis (MS) is currently hypothesized to be mediated by autoreactive T cells against myelin antigens. In Japanese, MS frequently and selectively affects the optic nerve and spinal cord. We have previously reported that the opticospinal form of MS (OS-MS) has been shown to be distinct from the conventional form of MS (C-MS) clinically, immunologically and immunogenetically. Recently, oligodendrocytes have been demonstrated to have plural origins, showing marked differences in distribution depending on their origin. We assumed that the specific autoantigens which exist in the optic nerve and spinal cord may be associated with development of OS-MS lesions.To identify the autoantigens in OS-MS, we made use of an immunoscreening of a human spinal cord cDNA expression library with serum samples obtained from patients with OS-MS. cDNA expression library was prepared from human spinal cord and 5 X 10^5 to 10 X 10^5 phage plaques were immunoscreened with sera obtained from eight OS- … More MS patients. Eleven positive immunoreactive clones were identified by their reactivity to the sera, and their sequences were analyzed. Comparisons of the sequences showed that these clones represented cDNAs from 5 distinct genes (HSP105, Rabaptin-5, NSD1, KIAA1640, KIAA0640). We produced GST-Rabaptin-5 fusion protein and HSP105 protein and evaluated the titer of IgG anti-Rabaptin-5 and anti-HSP105 autoantibody in sera and CSF, using ELISA. We found IgG anti-Rabaptin-5 reactivities were not significantly elevated, however IgG anti-HSP105 reactivities in MS patients was significantly higher than those in normal controls (p = 0.0193). Anti-HSP105 reactivities were found in 3 % (2/66) of normal controls, while 14.5 % (10/69) of patients with MS were positive for anti-HSP105 antibodies. The difference in prevalence of autoantibodies was not statistically significant between OS-MS and C-MS. The HSP105 α-reactive T cell lines derived from CD4^+CD45RO^+ T cells were established from 3 of 9 MS patients but not normal controls. Our findings indicate HSP105 to be a novel candidate autoantigen in MS. In future, we are going to analyze the other candidate autoantigens (NSD1, KIAA1640, KIAA0610). Less