Differences in the purification effect of carcinoembryonic antigen (CEA) from the three different hepatic metastases of rectum carcinoma.

Carcinoembryonic actigen (CEA) was purified from three liver metastases of carcinoma recti by a conventional procedure involving perchloric acid extraction of tumor tissue and fractionation of the extract by gel filtrations on Sepharose 4B and Sephadex G-200. The preparations obtained showed a different degree of heterogeneity in SDS-polyacrylamide gel electrophoresis and crossed immunoelectrophoresis, and also a different antigenic activity. One of preparations obtained was a homogeneous CEA by all these criteria, and two others showed heterogeneity and lower antigenic activity. The most heterogeneous CEA preparation was further purified by the affinity chromatography on Concanavalin A-Sepharose 4B and by DEAE-Sephadex A-50 chromatography and the usefulness of these procedures for purification of CEA is compared.