Rous Sarcomas in Chickens: Enhanced Growth Coexisting with Concomitant Immunity

Abstract
Chickens bearing Rous sarcoma virus-induced tumors in one wing did not develop new tumors when subsequently inoculated with Rous sarcoma virus in the other wing. However, the second inoculation of Rous sarcoma virus caused accelerated growth of the established tumors. This phenomenon was found to be bursa-dependent. Paradoxically, established tumors in bursectomized chickens grew at a diminished rate if the chickens were reinoculated with Rous sarcoma virus.