Protective tumor immunity induced by potassium chloride extracts of guinea pig hepatomas

Tumor-specific antigens of cells of the diethylnitrosamine-induced hepatomas in strain-2 guinea pigs were extracted with 3 M KCl. Immunization of normal animals with the extracted tumor antigens in adjuvant protected them against a subsequent challenge with viable tumor cells. Extracted tumor-specific antigens were less effective immunogens than viable tumor cells for both of two antigenically distinct lines.