ABSTRACT
ANTIGENIC PROPERTIES OF NEWCASTLE VIRUS LENTOGENIC STRAJNS. DETERMINATION OF THE 50% CHICK PROTECTIVE VALUE

Sergio Rosende O.1, Héctor Hidalgo O.1 y Enrique Bergqvist A.2
 

The lentogenic strains of the Newcastle disease virus: B1 (Hitcher), La Sota and Palo Alto were used to inmunize 25 day-old broiler chickens as la single clase. After 20 day they were chaIlenged with a velogenic isolate intramuscularly.
The chick protective clase 50 per cent (CPD50) value of eacn vaccine strain wa! shown to be 320 per intraocular dose. The heamagglutinating inhibiting (HI) antibody titer were not directly related to prctection.

Keywords:
1Méds. Vets., Departamento de Patología Veterinaria, Facultad de Medicina Veterinaria, Universidad de Chile. Casilla 13, Correo 15, Santiago, Chile.
2Méd. Vet., M. S., Programa Producción Avícola, Estación Experimental La Platina, Instituto de Investigaciones Agropecuarias, Casilla 10, La Granja, Santiago, Chile.