Dissemination of Rous Sarcoma Virus as a Cause of “Metastases”

Abstract

Chicks were given an inoculation of a cell-free preparation of Rous sarcoma virus into the wing web. After periods from 8 hours to 11 days, the inoculated wings were amputated under local anesthesia. Controls received the same virus inoculation but either were not amputated or had the uninoculated wing amputated. In the wing webs, sarcoma cells were first identified on day 4. On day 3 scattered cells of uncertain identity were sometimes found, but at 48 hours and earlier there was no evidence of tumor. Virus was not detectable by infectivity tests or by fluorescein-labeled antibody technique until day 4. The birds were killed at 15 or 25 days after inoculation so that the lungs could be studied for presence of tumors and virus, or were observed for 90 days to determine survival. Amputation of the virus-inoculated wing prior to day 5 delayed and decreased mortality and reduced the frequency with which sarcomas and Rous virus were found in lungs. However, even when amputation was performed 8, 16, 24, or 48 hours after inoculation, tumors and virus sometimes appeared in the lungs and some birds died of pulmonary sarcomas. Since amputation preceded appearance of sarcoma cells, these lung tumors must have resulted from early dissemination of virus from the inoculated wing.