BURSAL AND THYMIC LESIONS IN CHICKENS BEARING PROGRESSIVE ROUS SARCOMAS

Gross and microscopic examination of the bursa of Fabricius (BF) and thymus (Th) from chickens bearing progressive tumors induced by Rous sarcoma virus (RSV) revealed severe atrophic changes in both organs. In BF and Th from chickens that regressed the RSV-induced tumors appeared normal and were compatible with their counterparts from uninoculated control chickens. The functional significance of these non-neoplastic atrophic lesions observed in the central lymphoid organs of chickens with progressive RSV-induced tumors should be determined.