The Effect of Infection with Different Strains of Newcastle Disease Virus on Cellular RNA and Protein Synthesis

A large number of Newcastle Disease virus (NDV) strains have been isolated which differ markedly in their virulence for chickens (Waterson, Pennington & Allan, 1967), and which have been classified as velogenic (the most virulent), mesogenic (of intermediate virulence) and lentogenic (the least virulent). Investigation of the virus multiplication cycle in vitro has shown that a correlation exists between virulence and the ability to cause a cytopathic effect and form plaques in chick embryo cells (Schloer & Hanson, 1968; Reeve & Alexander, 1970); and recently Reeve & Poste (1971) have demonstrated a correlation between virulence and the ability to cause polykaryocytosis. It has also been suggested that a correlation exists between virulence and the ability to inhibit cellular protein synthesis (Reeve et al. 1971). We have examined the effect of infection with 13 strains of NDV on cellular RNA and protein synthesis, and have found several exceptions to the correlation observed by Reeve et al. (1971).