Chemical carcinogen-induced transplantable fibrosarcomas in histocompatible chickens. II. Effect of age and thymectomy on tumor incidence.
The incidence of primary fibrosarcoma 2-4 months after im injection of 7,12-dimethylbenz[a]anthracene (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 week of age, but thymectomized animals inoculated at 4 weeks 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 weeks of age produced a significantly lower incidence of tumors than did a similar dose of DMBA injected into chickens at 1-4 weeks of age. Thus DMBA-induced tumors in the chicken may present an interesting model for studies on immune surveillance.
D015127:9,10-Dimethyl-1,2-benzanthracene; D000367:Age Factors; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002060:Bursa of Fabricius / Q000502:physiology; D002642:Chick Embryo; D002645:Chickens; D005354:Fibrosarcoma / Q000139:chemically induced / Q000276:immunology*; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013934:Thymectomy; D013950:Thymus Gland / Q000502:physiology*
D015127:9,10-Dimethyl-1,2-benzanthracene