Concomitant immunity in hamsters bearing syngeneic transplants of tumors induced by para‐adenovirus 7, simian adenovirus 7, or 9,10‐dimethylbenzanthracene

Studies in an inbred line of hamsters have revealed that animals bearing tumor transplants reject a second graft of the same cells. This resistance was specific and was manifested against tumor cells induced by viruses (PARA‐adenovirus 7, simian adenovirus 7) or chemicals (9,10‐dimethylbenzanthracene). Studies designed to measure dose‐response revealed that tumor‐bearing hamsters were 10 to more than 100 times as refractory to challenge by a given cell line as were normal hamsters. Nevertheless, this immunity did not prevent continued growth of the primary transplant.