A thermostable antigen characteristic for carcinogen-induced rat intestinal tumors.

Precipitation tests using properly absorbed rabbit antisera revealed that PCA extracts of DMH-induced rat jejunal and colonic adenocarcinomas contain an antigen that is not detectable in extracts of normal rat tissue or other rat tumors. This rat tumor antigen was detected in extracts of normal rat colon by employing the much more sensitive procedure of tanned cell hemagglutination inhibition, however, the concentration of the antigen in tumor was about 250-fold higher than in normal colon. Similar to human CEA, the rat tumor antigen was found to be heat stable, contained glycoprotein, migrated as a beta-globulin, and appeared at a high concentration in fetal intestines, however, the rat tumor antigen was serologically distinct from human CEA.