Ochi Y, Fujiyama Y, Hosoda S, Miyazaki T, Yoshimura M, Hachiya T, Kajita Y
Clin Chim Acta. 1982 Jul 1;122(2):145-60. doi: 10.1016/0009-8981(82)90274-1.
We have demonstrated that 125 I-CEA (carcinoembryonic antigen) from two commercial sources (Roche and CIS RIA kit) can be precipitated by antibody to alpha 1-acid glycoprotein (AG) dose-dependently. The binding of 125 I-CEA to anti-AG can be displaced by unlabelled AG, though, there was no cross-reaction between AG and anti-CEA. The data strongly suggest that CEA has an immunological similarity to AG. The perchloric acid extract from cancerous tissue was fractionated on a Sephadex G-200 column, and the first eluted fraction (containing large amounts of CEA) was subjected to affinity chromatography using anti-AG bound to Sepharose. The bound fraction was eluted, labelled with 125 I, and then applied to a Sephadex G-200 column with carrier protein. The radioactivity was found mainly in the large molecular size eluted fraction (Fr 1). Almost all radioactivity of Fr 1 was precipitated by anti-AG and anti-CEA. This experiment also demonstrated that a large molecular weight component (Mr: 180 000) obtained from tumor was immunologically related to both CEA and AG. Based on differences in binding affinities between CEA with anti-CEA and with anti-AG we postulate that CEA may be a large molecular precursor of AG (big form of AG).
我们已经证明，来自两种商业来源（罗氏和CIS放射免疫分析试剂盒）的125I-癌胚抗原（CEA）可被抗α1-酸性糖蛋白（AG）抗体剂量依赖性沉淀。未标记的AG可取代125I-CEA与抗AG的结合，不过，AG与抗CEA之间没有交叉反应。这些数据有力地表明CEA与AG具有免疫学相似性。癌组织的高氯酸提取物在Sephadex G-200柱上进行分级分离，第一个洗脱级分（含有大量CEA）使用与琼脂糖结合的抗AG进行亲和色谱分析。洗脱结合的级分，用125I标记，然后与载体蛋白一起应用于Sephadex G-200柱。放射性主要出现在大分子大小的洗脱级分（级分1）中。级分1的几乎所有放射性都可被抗AG和抗CEA沉淀。该实验还证明，从肿瘤中获得的一种大分子成分（分子量：180000）在免疫学上与CEA和AG都相关。基于CEA与抗CEA和抗AG之间结合亲和力的差异，我们推测CEA可能是AG的大分子前体（AG的大形式）。
