Strains of Rous Sarcoma Virus

SHIPMAN, CHARLES, JR. (Indiana University School of Medicine, Indianapolis), AND ALVIN S. LEVINE. Selective response of the Japanese quail to various strains of Rous sarcoma virus. J. Bacteriol. 92:161-163. 1966.-The Bryan "high-titer," CarrZilber, Harris, Prague, Schmidt-Ruppin, and "29" strains of Rous sarcoma virus were used to initiate tumors in the Japanese quail (Coturnix coturnix japonica). Although all strains produced tumors upon primary inoculation, only the Bryan "high-titer" and Harris strains could be serially passaged with cell-free tumor extracts. Analysis by means of the end-point dilution technique and the interference test revealed that the tumor extract of the Bryan "high-titer" strain passaged 10 times in the quail contained a Rous-associated virus. It was previously reported (6, 7, 8) that mature Japanese quail are susceptible to the oncogenic effect of the Bryan standard strain of Rous sarcoma virus (RSV). A cytopathogenic effect is also evoked in quail tissue culture (1), and pocks are produced on the chorioallantoic membrane of the quail (6, 7). Studies were initiated in this laboratory to determine the susceptibility of the T-2 line of Japanese quail to other strains of RSV. Since it had been reported that avian leukosis viruses could not be propagated in the Japanese quail (6, 7), it was also of interest to determine how those strains known to be defective (3) could be serially passaged in a species supposedly resistant to the growth of Rous-associated helper viruses. MATERIALS AND METHODS Japanese quail. Fertile T-2 line Japanese quail eggs were obtained from Truslow Farms, Inc., Chestertown, Md., and Westbrook's Game Bird Farm, Brandon, Fla. All quail were raised and maintained in isolation. Chickens. Specific-pathogen-free eggs (white leghom strain 813) for tissue culture procedures and for the raising of adult chickens were obtained from Kimber Farms, Inc., Fremont, Calif. Chickens were raised and maintained in isolation. Viruses. The Bryan "high-titer" strain (BH-RSV; lot no. TV 11-19) and the Schmidt-Ruppin strain (SR-RSV; lot no. SR-9) of RSV were kindly supplied by W. Ray Bryan of the National Cancer Institute, Bethesda, Md. The Carr-Zilber strain (CZ-RSV) and the Harris strain (H-RSV) of RSV were generously supplied by R. J. C. Harris, Imperial Cancer Research Fund, London, England. The Prague strain (P-RSV) and the "29" strain (29-RSV) were obtained through the courtesy of Robert M. Dougherty, Upstate Medical Center, State University of New York, Syracuse, N.Y. All virus strains have been passaged in specific-pathogen-free chickens in this laboratory. Those virus strains to be tested were diluted in medium 199 containing 8% newbom calf serum (Hyland Laboratories, Los Angeles, Calif.) and 10% tryptose phosphate broth so that 1 ml of the virus suspension contained 104 FFU (focus-forming units) of virus. All virus preparations were stored at -70 C in sealed ampoules. Assay procedures. Tissue culture and RSV assay techniques were essentially those described by Rubin (10). Tumor production and methods of tumor extraction. Mature quail were inoculated in the wing web with 0.1 ml of the virus suspension to be tested. Quail in which tumors had appeared most rapidly were sacrificed by 95% nitrogen-5% carbon dioxide asphyxiation. This procedure is rapid and avoids the possible contamination of the tumors by ether or chloroform. "S3" crude virus pools were prepared from tumors by enzymatic digestion, homogenization, and differential centrifugation, according to the method of Moloney (5). End-point dilution technique and interference test. To investigate the possible presence of Rous-associated viruses in the tenth quail-passaged BH-RSV tumor extract (BH-RSV-QlO), a series of 10and 2-fold dilutions of the extract was made to the end point of RSV titer, followed by a series of 2-fold dilutions until the end point was exceeded by a factor of 10 (see Table 2). The fluid, agar, and cell sheet 161 on O cber 2, 2017 by gest http/jb.asm .rg/ D ow nladed fom