THE IMMUNOGENICITY OF NEWCASTLE DISEASE VIRUS

Abstract

The immunogenicity of formalin-inactivated and distilled water diluted Newcastle disease virus-vaccines was comparatively studied. The formalin-inactivated virus-vaccine showed that : (1) It induced highest hemagglutination-inhibition antibody response in chickens after primary and secondary vaccination. (2) It protected vaccinated flock from cessation of egg production after immunization. (3) An increase of its concentration induced batter immunity in day 4 chicks. (4) It induced little amount of virus-neutralizing antibody in primary response. (5) The study showed that there was a close relationship in immune response between the ages of immunized chickens and the development of lymphatic organs. Finally, the practical value of formalin-inactivated virus-vaccine was discussed.