Ramsden D A, Chen J, Miller F W, Misener V, Bernstein R M, Siminovitch K A, Tsui F W
Department of Immunology, University of Toronto, Ontario, Canada.
J Immunol. 1989 Oct 1;143(7):2267-72.
Autoantibodies that bind aminoacyl-tRNA synthetases are strongly associated with the human inflammatory myopathies polymyositis and dermatomyositis, but their molecular origins and relationship to pathogenesis are not known. To address these issues, we wished to identify the autoantigenic epitopes which react with these autoantibodies and to this end, we previously isolated a full length cDNA clone encoding the target Ag recognized most frequently by myositis sera, histidyl-tRNA synthetase (HRS). In the present study, we have analyzed the HRS autoepitopes by two amino acid insertion linker mutagenesis of HRS proteins expressed in Cos 1 cells. A series of mutant HRS cDNA were constructed and the expressed proteins were tested for enzyme activity and for immune reactivity with a panel of sera with anti-Jo-1 antibodies. Immunoblotting and immunoprecipitation analyses revealed that anti-Jo-1 antibodies recognize multiple conformation-dependent and independent epitopes on HRS and that the autoepitopes vary among different myositis patients.
与氨酰 - tRNA合成酶结合的自身抗体与人类炎症性肌病多肌炎和皮肌炎密切相关，但其分子起源及与发病机制的关系尚不清楚。为解决这些问题，我们希望鉴定与这些自身抗体发生反应的自身抗原表位，为此，我们先前分离出一个全长cDNA克隆，其编码肌炎血清最常识别的靶抗原，即组氨酰 - tRNA合成酶（HRS）。在本研究中，我们通过对在Cos 1细胞中表达的HRS蛋白进行两个氨基酸插入连接子诱变来分析HRS自身表位。构建了一系列突变HRS cDNA，并对表达的蛋白进行酶活性检测以及与一组抗Jo - 1抗体血清的免疫反应性检测。免疫印迹和免疫沉淀分析显示，抗Jo - 1抗体识别HRS上多个构象依赖性和非依赖性表位，且不同肌炎患者的自身表位有所不同。
