Concentration of human respiratory syncytial virus using ammonium sulfate, polyethylene glycol or hollow fiber ultrafiltration.

Human respiratory syncytial virus was concentrated by polyethylene glycol or ammonium sulfate precipitation as well as by hollow ultrafiltration. Recoveries obtained were respectively 49.4%, 47.7%, and 75.2%; however, further analysis of these results by resuspension experiments showed that all the infectivity could be recovered from the different concentrates. The protein content of polyethylene glycol concentrates was much lower than those of ammonium sulfate or hollow fiber ultrafiltration. Electron microscopy revealed that the morphological integrity of virus particles was unaffected by the concentration methods used. Purified virus was obtained when polyethylene glycol concentrates were centrifuged through two successive density gradients.