Methylcholanthrene-induced tumors in resistant and sensitive Jensen sarcoma rats. i. effect of fresh prepared MC emulsion.

By two subcutaneous or intramuscular injections of 20-methylcholanthrene (MC), 5 mg/animal in vegetal oil, followed after 74 days by 10 mg of MC emulsion, sarcomata were obtained in 63.6% of Jensen sarcoma-resistant rats (R) and in 36.8% of Jensen sarcoma-sensitive rats (S). One of the induces sarcomas, transplanted from R to R and then to S rats, presented a very high antigenicity: it strongly immunised receptive rats against the induced sarcoma and also, in a lower degree, against the Jensen sarcoma. Antigenicity was maintained up to the tenth passage.