Ahmed A E, Whaley K
Department of Pathology, University of Glasgow, Western Infirmary, U.K.
Immunology. 1988 May;64(1):45-50.
A pre-albumin glycoprotein that inhibits complement-mediated prevention of immune precipitation (PIP) has been purified from normal human serum by sequential affinity chromatography on IgG-Sepharose, protein A-Sepharose and Con A-Sepharose. A total of 4.7 mg of this protein were obtained from 50 ml of serum, representing a yield of 49% and a 253-fold degree of purification. We have named this glycoprotein gp60 as it has an apparent molecular weight of 60,000 on SDS-PAGE. The addition of gp60 to normal serum produced dose-dependent inhibition of both PIP and solubilization of immune precipitates. Maximum inhibition of PIP was achieved by a concentration of 600 micrograms/ml. A monospecific antiserum was produced by the immunization of rabbits, which enabled us to develop an enzyme-linked immunosorbent assay to measure serum concentrations of gp60. In 12 normal sera the mean concentration was 205 micrograms/ml (range 132-258 micrograms/ml), while that in 15 rheumatoid arthritis sera was 515 micrograms/ml (range 430-708 micrograms/ml). The serum concentration of this protein correlated with the level of inhibition of PIP (r = 0.91, P less than 0.01).
一种抑制补体介导的免疫沉淀阻止作用（PIP）的前清蛋白糖蛋白已通过在IgG-琼脂糖、蛋白A-琼脂糖和伴刀豆球蛋白A-琼脂糖上的连续亲和层析从正常人血清中纯化出来。从50毫升血清中总共获得了4.7毫克这种蛋白质，产率为49%，纯化程度为253倍。由于它在SDS-聚丙烯酰胺凝胶电泳上的表观分子量为60,000，我们将这种糖蛋白命名为gp60。向正常血清中添加gp60会产生剂量依赖性地抑制PIP和免疫沉淀物的溶解。PIP的最大抑制作用在浓度为600微克/毫升时实现。通过免疫兔子产生了一种单特异性抗血清，这使我们能够开发一种酶联免疫吸附测定法来测量血清中gp60的浓度。在12份正常血清中，平均浓度为205微克/毫升（范围为132 - 258微克/毫升），而在15份类风湿性关节炎血清中为515微克/毫升（范围为430 - 708微克/毫升）。这种蛋白质的血清浓度与PIP的抑制水平相关（r = 0.91，P < 0.01）。
