Singh A K, Makker S P
Immunology. 1986 Mar;57(3):467-72.
Previously, we have isolated and characterized a complex glycoprotein antigen (gp600) from the rat kidney that can induce Heymann nephritis (HN) in the rat. A monospecific antibody against the gp600 was used as a probe to document the existence of cross-reactive antigens in normal rat serum. A competitive radioimmunoassay measured the concentration in normal rat serum as being 45.5 +/- 10.2 micrograms/ml (n = 17). Molecular exclusion gel chromatography of normal rat serum identified gp600 activity in three distinct peaks corresponding to the molecular weights of 150,000, 110,000 and 70,000, respectively. Soluble immune complexes of mean molecular weight 1.1 X 10(6) were formed when normal rat serum was reacted with affinity-purified 125I anti-gp600. Normal rat serum, electrophoresed in 8% SDS-PAGE gels, transblotted to nitrocellulose membrane and reacted with anti-gp600 by indirect immunoperoxidase technique, identified three to four bands in the molecular weight region of 66,000-80,000. Isoelectric focusing revealed these antigens to be anionic (pI of 4.5-5.5) in nature. We conclude that normal rat serum contains antigens that cross-react with gp600. Further, these antigens are anionic in nature and form soluble immune complexes with anti-gp600 in vitro. The relevance of these findings to the pathogenesis of HN is discussed.
此前，我们已从大鼠肾脏中分离并鉴定出一种复合糖蛋白抗原（gp600），该抗原可在大鼠中诱发海曼肾炎（HN）。一种针对gp600的单特异性抗体被用作探针，以证明正常大鼠血清中存在交叉反应性抗原。竞争性放射免疫测定法测得正常大鼠血清中的浓度为45.5±10.2微克/毫升（n = 17）。对正常大鼠血清进行分子排阻凝胶色谱分析，在三个不同的峰中鉴定出gp600活性，其分子量分别对应于150,000、110,000和70,000。当正常大鼠血清与亲和纯化的125I抗gp600反应时，形成了平均分子量为1.1×10(6)的可溶性免疫复合物。在8% SDS-PAGE凝胶中进行电泳、转印至硝酸纤维素膜并通过间接免疫过氧化物酶技术与抗gp600反应的正常大鼠血清，在分子量为66,000 - 80,000的区域中鉴定出三到四条带。等电聚焦显示这些抗原本质上是阴离子型的（pI为4.5 - 5.5）。我们得出结论，正常大鼠血清中含有与gp600发生交叉反应的抗原。此外，这些抗原本质上是阴离子型的，并且在体外与抗gp600形成可溶性免疫复合物。本文讨论了这些发现与HN发病机制的相关性。
