Antigenic changes in nuclear chromatin in 1,2-dimethylhydrazine-induced colon carcinogenesis

Chromosomal nonhistone protein-DNA complexes prepared from rat colon adenocarcinoma were used to produce tumor specific antisera in rabbits. The antisera reacted specifically in complement fixation tests with chromatins isolated from rat colon tumor and not with those from a number of other rodent tumors and normal tissues, including normal rat colon epithelial cells. Tumor specificity of this antisera was also demonstrated by their cross reactivity with human and mouse colon adenocarcinomas. Immunohistochemical localization of the antigens by the horseradish peroxidase bridge technique demonstrated their presence in the nuclei. The changes in the immunospecificity of the nuclear antigens in chromatin were studied in colon of rats treated with 1,2-dimethylhydrazine. A significant change in the immunospecificity of the chromatin occurred as early as the fourth week after 1,2-dimethylhydrazine treatment was begun.