Ochi Y, Ura Y, Hamazu M, Fujiyama Y, Kajita Y, Ishida M, Miyazaki T, Tamura K
Clin Chim Acta. 1984 Mar 27;138(1):9-19. doi: 10.1016/0009-8981(84)90349-8.
An immunochemical characterization of carcinoembryonic antigen (CEA) and NCA (non-specific cross-reacting antigen) was performed. Positive reactions of CEA and NCA (Mr 60 000) with some antibodies to alpha 1-acid glycoprotein (AG) were observed. Thus, both antigens may contain immune determinants in common with alpha 1-acid glycoprotein. CEA showed positive reactivity with anti-NCA. NCA showed positive reactivity with either polyclonal or monoclonal antibodies to CEA, but negative reactivity with auto-antibodies to CEA. 125I-Tetracosapeptide (synthetic peptide-24 corresponding to the amino terminal sequence of CEA) failed to react with any antisera against CEA, NCA and AG. 125I-AG also showed no immuno-reaction with any antibody against CEA, NCA and tetracosapeptide. These results suggest that some monoclonal antibodies to CEA are directed against a common antigenic determinant of both CEA and NCA in addition to AG and tetracosapeptide, and that the auto-antibody to CEA is directed against a unique immune determinant which is not common to NCA. Thus, CEA appears to contain a unique determinant not found in NCA. Similarities in the composition of both amino acids and carbohydrates of CEA and NCA suggest that CEA is 'big-big' AG and NCA is 'big' AG.
对癌胚抗原（CEA）和NCA（非特异性交叉反应抗原）进行了免疫化学特性分析。观察到CEA和NCA（分子量60000）与一些抗α1-酸性糖蛋白（AG）抗体呈阳性反应。因此，这两种抗原可能含有与α1-酸性糖蛋白共有的免疫决定簇。CEA与抗NCA呈阳性反应。NCA与抗CEA的多克隆或单克隆抗体呈阳性反应，但与抗CEA自身抗体呈阴性反应。125I-二十四肽（与CEA氨基末端序列对应的合成肽-24）未能与任何抗CEA、NCA和AG的抗血清发生反应。125I-AG也未与任何抗CEA、NCA和二十四肽的抗体发生免疫反应。这些结果表明，一些抗CEA单克隆抗体除针对AG和二十四肽外，还针对CEA和NCA的共同抗原决定簇，并且抗CEA自身抗体针对的是NCA所没有的独特免疫决定簇。因此，CEA似乎含有NCA中未发现的独特决定簇。CEA和NCA在氨基酸和碳水化合物组成上的相似性表明，CEA是“大大”AG，NCA是“大”AG。
