Buchegger F, Schreyer M, Carrel S, Mach J P
Int J Cancer. 1984 May 15;33(5):643-9. doi: 10.1002/ijc.2910330515.
During the selection of monoclonal antibodies (MAb) raised against purified carcinoembryonic antigen (CEA), two MAbs were identified which immunoprecipitated a glycoprotein of 95 kD present both in perchloric acid extracts of normal lung and on the surface of normal granulocytes. This antigen was distinct from the previously reported normal glycoprotein crossreacting with CEA (NCA) which had a molecular weight of 55 kD. The difference between the smaller and the larger crossreacting antigens termed NCA-55 and NCA-95, respectively, was demonstrated by SDS-polyacrylamide gel electrophoresis, by elution from Sephadex-G200 and by selective binding to a series of anti-CEA MAb. Out of six MAb which all bound CEA purified from colon carcinoma, three did not react with these two crossreacting antigens, one bound only NCA-95, one reacted only with NCA-55 and one reacted with both NCA-55 and NCA-95. Immunoadsorbent purified preparations of 125I labelled NCA-95 and NCA-55 were found useful for the screening of new anti-CEA MAb. In addition, when tested on frozen sections of colon carcinoma, normal spleen, normal lung and pancreas, each type of MAb gave a clearly different pattern of reactivity. The three anti-CEA MAb which did not bind any of the crossreacting antigens stained only the colon carcinoma cells; the MAb binding to either one of the two types of NCA gave a similar pattern of reactivity both on colon carcinoma cells and on granulocytes. However, on normal lung and pancreas, the MAb binding NCA-55 stained granulocytes as well as bronchiolar and alveolar epithelial cells in lung and inter- and intra-lobular duct epithelial cells in pancreas, whereas the MAb binding only NCA-95 stained only the granulocytes. Thus, the newly identified NCA-95 appears to differ from NCA-55 not only in terms of molecular size and antigenicity but also by the fact that in normal lung and pancreas it is found in granulocytes but not in epithelial cells.
在筛选针对纯化癌胚抗原（CEA）产生的单克隆抗体（MAb）过程中，鉴定出两种单克隆抗体，它们能免疫沉淀一种95kD的糖蛋白，该糖蛋白存在于正常肺的高氯酸提取物中以及正常粒细胞表面。这种抗原与先前报道的与CEA发生交叉反应的正常糖蛋白（NCA，分子量为55kD）不同。通过SDS-聚丙烯酰胺凝胶电泳、从Sephadex-G200上洗脱以及与一系列抗CEA单克隆抗体的选择性结合，证实了分别称为NCA-55和NCA-95的较小和较大交叉反应抗原之间的差异。在六种均能结合从结肠癌中纯化的CEA的单克隆抗体中，三种不与这两种交叉反应抗原发生反应，一种仅与NCA-95结合，一种仅与NCA-55反应，一种与NCA-55和NCA-95均反应。发现免疫吸附纯化的125I标记的NCA-95和NCA-55制剂可用于筛选新的抗CEA单克隆抗体。此外，当在结肠癌、正常脾脏、正常肺和胰腺的冰冻切片上进行检测时，每种类型的单克隆抗体都呈现出明显不同的反应模式。三种不结合任何交叉反应抗原的抗CEA单克隆抗体仅对结肠癌细胞染色；与两种类型的NCA之一结合的单克隆抗体在结肠癌细胞和粒细胞上呈现出相似的反应模式。然而，在正常肺和胰腺上，结合NCA-55的单克隆抗体可对粒细胞以及肺中的细支气管和肺泡上皮细胞以及胰腺中的小叶间和小叶内导管上皮细胞进行染色，而仅结合NCA-95的单克隆抗体仅对粒细胞进行染色。因此，新鉴定出的NCA-95似乎不仅在分子大小和抗原性方面与NCA-55不同，而且还在于在正常肺和胰腺中它存在于粒细胞而非上皮细胞中。
