Glycoproteins, cross-reacting with carcinoembryonic antigen (CEA), were found in normal human feces (NFA-2) and meconium (NCA-2). These three antigens are considered as the same gene products. Comparative study of their sugar chain structures, however, revealed that they have different sets of N-linked sugar chains reflecting the developmental and malignant transformational changes of the sugar chains of colon glycoproteins. High mannose type sugar chains and C2,4-branched biantennary sugar

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... ns were found only in CEA. The branching structures of the complex type sugar chains of the three antigens are almost the same. However, Type 1 chain is detected in the outer chain moieties of NFA-2 and NCA-2 but not in those of CEA. All three antigens contain sulfated and sialylated sugar chains. The acidic sugar chains of NFA-2 and NCA-2 contain the GalP1+3(HS03-+6)GlcNAc and the Neu5Aca2+3GalPl+3GlcNAc groups. In contrast, the GalP1+4(HS03-+6)GlcNAc and the Neu5Aca2+6Gal~1+4GlcNAc groups are detected in CEA. Fig.1. Schematic model of CEA. Black triangles indicate the sugar chains.