%0 Journal Article %A Bronson, D. L. %A Elliott, A. Y. %A Ritzi, Donna %T A Comparison of Four Methods Used to Concentrate Rous Sarcoma Virus from Tissue Culture Fluids %D 1976 %J Journal of General Virology, %V 33 %N 3 %P 403-410 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-33-3-403 %I Microbiology Society, %X SUMMARY Three methods of pelleting, pelleting followed by Pronase treatment, polyethylene glycol (PEG)-Pronase, and diaflo ultrafiltration (diafiltration) were used to concentrate RSV (RAV-1) from tissue culture fluids. Sucrose-gradient fractions containing virus preparations which had been concentrated by diafiltration or pelleting were heavily contaminated with amorphous debris. This debris was not present in similar, gradient-purified preparations that had been concentrated by the PEG-Pronase or pellet-Pronase methods. Maximum recovery of radiolabelled virus particles and virion-associated RNA-dependent DNA polymerase activity was obtained in gradient fractions containing virus concentrates prepared by the pellet-Pronase and PEG-Pronase methods. Although there were slight differences in recovery by these two methods, the advantages of the PEG-Pronase method make it the preferred method, especially when large volumes of tissue culture fluids are used. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-33-3-403