Observations on the Synthesis of Carcinoembryonic Antigen by an Established Human Colonic Carcinoma Cell Line

Abstract

Some properties and kinetics of synthesis of the carcinoembryonic antigen (CEA-LoVo) produced by an established human colon carcinoma cell line were analyzed. CEA-LoVo was assayed by the method of Chu and Reynoso which was standardized against the activity of the First British Standard for CEA. CEA-LoVo was stable at -20 and 4.degree. C. At 37.degree. C, CEA-LoVo degraded at the rate of 1.4%/day in cell-free supernatants, and at the rate of 6.6%/day in the supernatants of monolayer cultures. CEA-LoVo was sensitive to enzymatic treatment (.apprx. 55% loss) and extraction of PCA [perchloric acid] (> 70% loss). The elution profile of CEA-LoVo in concanavalin A-sepharose B coincided with that of the First British Standard for CEA. No A or B blood group antigenic activity was noted. Studies employing immunofluorescent and horseradish peroxidase-labeled antibody techniques demonstrated heavy membrane and moderate intracytoplasmic localization. The greatest amount of net synthesis occurred for cells in stationary phase while CEA-LoVo release occurred maximally in lag phase.