TWEEN 80-SOLUBILIZED NEWCASTLE-DISEASE VIRUS PREPARED AS A WATER-IN-OIL-IN-WATER VACCINE

The Newcastle disease virus (NDV) was solubilized with 10% w/v Tween 8 0 and inactivated with 0.05% v/v formalin. The average molecular mass of the released antigenic subunits was 307 kD. The rested vaccine was prepared in the form of a water-in-oil-in-water emulsion (WOWE) vaccin e. The oil-to-aqueous ratio was 1:2. The solubilized NDV was administe red alone or built in a tetravalent WOWE vaccine. A dose of the monova lent vaccine containing an equivalent of 44.7 mu l of detergent-treate d NDV-allantoic fluid (NDV-AF) was sufficient for the complete protect ion of the commercially available chickens vaccinated at the age of 5 wk and challenged 7 wk later. The anti-NDV-free chickens, vaccinated a t 4 wk of age and challenged 2 wk postvaccination, were 100% and 73% p rotected by a vaccinal dose containing 178.6 and 89.3 yl of detergent- treated NDV-AF, respectively. Commercially available light pullers, pr imary vaccinated with live lentogenic NDV vaccine, generated a protect ive level of NDV antibodies after revaccination with WOWE vaccine cont aining 89.3 mu l of detergent treated NDV-AF. Laying hens were revacci nated under field conditions at the beginning of the laying cycle by t he terravalent vaccine. A vaccinal dose/bird containing 11.2 mu l of d etergent-treated NDV-AF elicited a long-lasting high level of NDV neut ralizing antibodies.