Host induced modifications of Newcastle disease virus virion polypeptides.

The polypeptide composition of Newcastle Disease Virus (NDV) virions grown in two host cell cystems--chorioallantlic membrane (CAM) and BHK-21 cells--was studied. Two strains of virus were compared, one highly virulent, the other completely avirulent. No significant differences in the polypeptide composition of the two strains of virus could be detected. However, differences were found in virions grown in different hosts, the same differences being found in both strains. An additional polypeptide is found in BHK grown virus which is not present in CAM grown virus and this is associated with a decreased relative amount of nucleocapsid protein in BHK grown virus. The possibility of this new polypeptide being a degradation product of the nucleocapsid protein is discussed. BHK grown virions also contain increased amounts of a polypeptide migrating to a position which might be expected of the FO precursor glycoprotein. However, in contrast to the FO polypeptide, this polypeptide does not appear to be glycosylated.