Studies on the Hemolytic Activity of Newcastle Disease Virus (NDV)

Abstract

The hemolytic activity of NDV, as present in allantoic fluid or suspended in phosphate buffered saline is greatly enhanced by dialysis against various media and by the diluents used in the titrations. It is most pronounced after dialysis against distilled water with subsequent restoration of isotonicity by sodium chloride and dilution in isotonic sodium citrate. The hemolytic activity of such preparations is further increased by various physical manipulations, i.e. sonic vibration, repeated freezing and thawing and osmotic shock. No evidence has been obtained as yet to indicate that these procedures cause the disruption of NDV into smaller hemolytic units.