PHYSICAL, CHEMICAL AND IMMUNOLOGICAL CHARACTERIZATION OF SALINE-EXTRACTED, CONCANAVALIN A PURIFIED CARCINOEMBRYONIC ANTIGEN

There has been concern that the utilization of perchloric acid (PCA) in the purification scheme of carcinoembryonic antigen (CEA) may alter the molecular properties of the final product. In order to investigate this possibility, CEA was extracted from tumor tissue utilizing saline instead of PCA and subsequently was purified according to procedures established for PCA-extracted CEA. As determined by chemical composition, electron microscopic analysis, isoelectric focusing, radioimmunoassay and immunodiffusion analysis, the molecular properties of the purified, saline-extracted CEA were nearly identical to those of CEA purified after PCA treatment. Slight differences were noted in length by electron microscopy; the CEA particles being on the average 20% longer for the saline material. In addition to their molecular similarities, there was no significant difference in the yield of CEA in the initial extract when different portions of the same tumor tissue were extracted with saline or PCA. These data indicate that the initial extraction with PCA, which significantly aids in the purification of CEA, does not significantly alter the molecular properties of the purified CEA product. © 1979.