Study of substances related to carcinoembryonic antigens, CEA-NCA and association with alpha1-antichymotrypsin.

The alpha-protein which we previously detected in PCA extracts of malignant tumours, normal tissues, sera and other body fluids has been further tested. The alpha-protein was identified by immunological methods as alpha1-antichymotrypsin. Experiments by crossed immunoelectrophoresis showed that this protein cross-reacts with the betaE-protein found in the PCA extracts. The betaE-protein shows heterogeneity in molecular size, electrophoretic mobility and it has been demonstrated that it shares antigenic determinants with the CEA or betaI-molecule. Cross-reaction between betaE and other glycoproteins found in the PCA extract of normal or malignant tissue or serum was not detected.