Induced resistance to an indigenous transplantable mouse tumor.

Although the literature contains many refer ences to successful attempts to immunize animals against transplantable tumors, few deal with transplantable spontaneous tumors in inbred strains, and, in general, the results of these latter experiments have been negative. Aptekman and his co-workers (1-3), in a series of studies with an alcohol-soluble extract of methylcholanthrene-induced transplantable rat sarcoma, produced oncolysis of tumors that arose in rats of their own inbred strain. A greater per centage of the animals so treated were resistant to subsequent implants of these tumors. However, these investigators failed to induce resistance in a recognized pure strain of mice using a transplantable spontaneous tumor.1