Fusion of erythrocytes by Newcastle disease virus.

Newcastle disease virus-induced fusion of chick embryo (CE) and chicken erythrocytes has been studied at the ph range between 5.5 and 8.0. The highest degree of fusion of CE erythrocytes was observed at pH 5.5, whereas the chicken erythrocytes fused at pH 5.5-6.0 only. Freezing and thawing of low-haemolytic virus preparation increased its erythrocyte fusion activity. Ammonium chloride did not cause a statistically significant effect on the multiplication of virus preparations expressing different haemolysis and erythrocyte fusion activity.