Influence of Total Body X-irradiation on Tumor Induction by Parotid Tumor Agent in Adult Mice

Summary Pleomorphic tumors of the parotid gland have been induced by PTA (polyoma virus) in non-immune adult C3Hf/BiLw mice given 300 r whole-body X-radiation. The latent period was long and few other primary sites were involved in tumor induction following intravenous injection of a virulent thymotrophic virus preparation. Thymic epithelial tumors, induced in 100% of mice injected in the neonatal period, did not appear in mice injected as adults. Thymectomy therefore could not be shown to have an influence on the expression of tumors in adultinjected mice. The response of X-rayed, adult C3Hf/BiLW mice receiving salivary gland explants exposed in vitro to PTA, was in contrast similar to the response of mice receiving virus within 24 hours post partum. Tumors arising at many primary sites in a relatively short period of time were observed. No differences were found in the pathogenesis of the tumors in the groups studied here. The typical renal cortical epithelial lesions characteristic of PTA infection in newborn mice were absent in those animals receiving virus as adults. The authors are indebted to Mr. Britton Smith and Mr. Willie Morgan for technical assistance and to Mr. Gebhard Gsell for photography.