BACKGROUND Autoimmune diseases result from aberrant immune attacks by the body itself. It is mysterious how autoantigens, a large cohort of seemingly unconnected molecules expressed in different parts of the body, can induce similar autoimmune responses. We have previously found that dermatan sulfate (DS) can form complexes with molecules of apoptotic cells and stimulate autoreactive CD5+ B cells to produce autoantibodies. Hence, autoantigenic molecules share a unique biochemical property in their affinity to DS. This study sought to further test this uniform principle of autoantigenicity. RESULTS Proteomes were extracted from freshly collected mouse livers. They were loaded onto columns packed with DS-Sepharose resins. Proteins were eluted with step gradients of increasing salt strength. Proteins that bound to DS with weak, moderate, or strong affinity were eluted with 0.4, 0.6, and 1.0 M NaCl, respectively. After desalting, trypsin digestion, and gel electrophoresis, proteins were sequenced by mass spectrometry. To validate whether these proteins have been previously identified as autoantigens, an extensive literature search was conducted using the protein name or its alternative names as keywords. Of the 41 proteins identified from the strong DS-affinity fraction, 33 (80%) were verified autoantigens. Of the 46 proteins with moderate DS-affinity, 27 (59%) were verified autoantigens. Of the 125 proteins with weak DS-affinity, 44 (35%) were known autoantigens. Strikingly, these autoantigens fell into the classical autoantibody categories of autoimmune liver diseases: ANA (anti-nuclear autoantibodies), SMA (anti-smooth muscle autoantibodies), AMA (anti-mitochondrial autoantibodies), and LKM (liver-kidney microsomal autoantigens). CONCLUSIONS This study of DS-affinity enrichment of liver proteins establishes a comprehensive autoantigen-ome for autoimmune liver diseases, yielding 104 verified and 108 potential autoantigens. The liver autoantigen-ome sheds light on the molecular origins of autoimmune liver diseases and further supports the notion of a unifying biochemical principle of autoantigenicity.

中文翻译：

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从肝组织蛋白的硫酸皮肤素亲和力富集确定的自身免疫性肝病的全面自身抗原组。

背景技术自身免疫疾病是由身体自身的异常免疫攻击引起的。人体抗原是在人体不同部位表达的大量看似未连接的分子，如何诱导相似的自身免疫反应，这是一个谜。我们以前已经发现硫酸皮肤素（DS）可以与凋亡细胞分子形成复合物，并刺激自身反应性CD5 + B细胞产生自身抗体。因此，自身抗原分子在与DS的亲和力方面具有独特的生化特性。这项研究试图进一步测试这种自身抗原性的统一原理。结果从新鲜收集的小鼠肝脏中提取蛋白质组。将它们加载到装有DS-Sepharose树脂的柱子上。用增加盐强度的逐步梯度洗脱蛋白质。与DS结合的蛋白具有弱，中等，亲和力或强亲和力分别用0.4、0.6和1.0 M NaCl洗脱。脱盐，胰蛋白酶消化和凝胶电泳后，通过质谱对蛋白质进行测序。为了验证这些蛋白质先前是否已被鉴定为自身抗原，使用蛋白质名称或其替代名称作为关键词进行了广泛的文献检索。从强DS亲和力组分中鉴定出的41种蛋白质中，有33种（80％）被证实是自身抗原。在具有中等DS亲和力的46种蛋白质中，有27种（59％）被证实是自身抗原。在DS亲和力较弱的125种蛋白质中，有44种（35％）是已知的自身抗原。令人惊讶的是，这些自身抗原属于自身免疫性肝病的经典自身抗体类别：ANA（抗核自身抗体），SMA（抗平滑肌自身抗体），AMA（抗线粒体自身抗体）和LKM（肝肾微粒体自身抗原）。结论这项关于DS亲和力富集肝蛋白的研究建立了一个针对自身免疫性肝病的综合自身抗原组，可产生104种经过验证的自身抗原和108种潜在的自身抗原。肝脏自身抗原组阐明了自身免疫性肝病的分子起源，并进一步支持了统一的自身抗原生化原理的概念。