Hajoui O, Martin S, Alvarez F
Service de Gastroentérologie, Hôpital Sainte-Justine, Université de Montréal, Quebec, Canada.
Clin Exp Immunol. 1998 Sep;113(3):339-45. doi: 10.1046/j.1365-2249.1998.00673.x.
The aim of this study was to identify the epitopes recognized by antibodies to the asialoglycoprotein receptor, a specific hepatocyte protein, from sera of patients with autoimmune hepatitis. An ELISA test was used to detect anti-asialoglycoprotein receptor antibodies in the sera of patients with autoimmune hepatitis. Positive sera were tested against the same antigen by slot blot, by Western blot and by immunoprecipitation of the untreated protein and following treatment with beta-mercaptoethanol (beta-ME) and endoglycosidase F. The mature, unglycosylated and partially glycosylated forms of the asialoglycoprotein receptor synthesized by HepG2 cells were tested against positive patients' sera, as well as the in vitro translated unglycosylated form of the H1 subunit of the receptor. Sera from patients with autoimmune hepatitis recognized equally the native form, as well as the beta-ME-modified form, but less well the deglycosylated form of the human mature receptor. No reactivity was found when these sera were tested against the denatured human protein. In addition, neither the unglycosylated H1 subunit nor any of the HepG2-synthesized asialoglycoprotein receptor forms bound to the antibodies. Altogether, these results show that anti-asialoglycoprotein receptor antibodies in the sera of patients with autoimmune hepatitis are directed against conformational structures of the mature hetero-oligomeric form of the human liver protein and that at least some epitopes were located on the extracellular domain of the antigen.
本研究的目的是从自身免疫性肝炎患者的血清中鉴定出与去唾液酸糖蛋白受体（一种特异性肝细胞蛋白）抗体识别的表位。采用酶联免疫吸附测定（ELISA）检测自身免疫性肝炎患者血清中的抗去唾液酸糖蛋白受体抗体。通过狭缝印迹、蛋白质印迹以及对未处理的蛋白质、经β-巯基乙醇（β-ME）处理的蛋白质和经内切糖苷酶F处理的蛋白质进行免疫沉淀，对阳性血清进行相同抗原检测。用HepG2细胞合成的去唾液酸糖蛋白受体的成熟、未糖基化和部分糖基化形式，以及该受体H1亚基的体外翻译未糖基化形式检测阳性患者血清。自身免疫性肝炎患者的血清对人成熟受体的天然形式以及β-ME修饰形式的识别程度相同，但对去糖基化形式的识别程度较低。当用这些血清检测变性的人蛋白质时，未发现反应性。此外，未糖基化的H1亚基以及任何HepG2合成的去唾液酸糖蛋白受体形式均未与抗体结合。总之，这些结果表明，自身免疫性肝炎患者血清中的抗去唾液酸糖蛋白受体抗体针对的是人类肝脏蛋白成熟异源寡聚体形式的构象结构，并且至少一些表位位于抗原的细胞外结构域。
