The capacity of avian retrovirus-induced sarcomas to expand by infectious virus production

Sarcomas arising in FP chickens infected with subgroup B avian sarcoma virus at increasing times posthatch were compared for their capacity to mediate recruitment of new sarcoma cells by infectious virus production. This comparison was premised on the observation that primary sarcoma growth is much slower when older chickens are infected with avian sarcoma virus. As measured in a transplantation assay, no age-related diminution in the recruitment capacity of sarcoma tissue from virus-infected transplant donors was observed, despite the marked age-related differences in their patterns of primary sarcoma growth. These observations establish that a diminished recruitment capacity is not required for slow primary sarcoma growth. The capacity to induce the formation of sarcomas at sites distal to the primary sarcoma was correlated with a strong recruitment capacity.