Studies on carcinoembryonic and related antigens in malignant tumours of colon-rectum.

Abstract

Antisera against perchloric acid extract of adenocarcinomas of the large bowel were produced in four rabbits. The activity of these tumour antisera were further characterized. Antibodies were demonstrated against antigenic determinants on two proteins with β‐mobility, referred to as βI and βE The βI‐protein possessed antigens which were found to be identical to GOLD's CEA.βE as well as βI‐antigens were demonstrated by immune‐diffusion experiments in all the twelve tumour extracts which were tested. The amount of tumour associated β‐proteins varied more than ten‐fold in different tumour extracts. Absorption experiments showed that the βE‐protein was present also in the non‐tumour extract in small amounts, but no evidence was obtained that the non‐tumour extract possessed βI‐ or CEA‐protein. Observations are presented which indicate that the βI‐molecules, in addition to specific antigenic sites, also possess antigenic determinants which seems to be shared by the βE‐molecules. The two proteins show great electrophoretic heterogeneity, but no polymorphism was detected in the β‐globulins by antigen‐antibody crossed electrophoresis. The four antisera also showed activity against a third protein which was not further characterized.