Chemical carcinogen-induced transplantable fibrosarcomas in histocompatible chickens. II. Effect of age and thymectomy on tumor incidence
Hirota, Y.; Galton, J.; Lerman, S.P.; Palladino, M.A.; Thorbecke, G.J.
Journal of the National Cancer Institute 65(3): 595-601
1980
ISSN/ISBN: 0027-8874 PMID: 6774152 Document Number: 154985
The incidence of primary fibrosarcoma 2-4 mo. after i.m. injection of 7,12-dimethylbenzanthracene (DMBA) was studied in normal, neonatally thymectomized and bursectomized SC (B2/B2) chickens. The tumor incidence was not significantly increased in thymectomized chickens inoculated at 1 wk of age, but thymectomized animals inoculated at 4 wk of age developed a higher incidence of tumors than did controls. Bursectomy did not affect tumor induction. Whereas thymectomy and bursectomy clearly reduced T- and B-cell immune responses, respectively, neither the carcinogen nor the presence of tumor had a detectable effect on the immune response. The effect of varying the age of chickens at the time of carcinogen injection was also studied. DMBA injected into chickens at 8-12 wk of age produced a significantly lower incidence of tumors than did a similar dose of DMBA injected into chickens at 1-4 wk of age. Thus, DMBA-induced tumors in the chicken may present a model for studies on immune surveillance.