RS virus components. I. Isolation and purification.

RS virus was centrifuged in zonal rotor on 55% sucrose cushion. Three layers were collected: light (RS-LL) containing complement-fixing antigen, medium (RS-ML) containing both complement-fixing and virus particle antigens, and heavy (RS-HL) containing antigen associated with the virus particle. RS-LL was chromatographed on Sephadex G-200 column. Two peaks were obtained, containing complement-fixing activity (RS-LL-1 and RS-LL-2). After sonication (20 Hz, 30 min) RS-ML and RS-HL also were chromatographed on Sephadex G-200 column. Two protein peaks were obtained from each layer (RS-ML-1 and RS-ML-2 from medium, and RS-HL-1 and RS-HL-2 from the heavy layer), corresponding to RS virus proteins.