1a. Objectives (from AD-416)
1. Determine vaccine efficacy following vaccination with inactivated Newcastle disease virus antigen vaccine against highly pathogenic Newcastle disease virus challenge. 2. Determine seroconversion against Newcastle disease virus (NDV) following vaccination of 4 week old specific pathogen free (SPF) chickens with inactivated NDV vaccines.
1b. Approach (from AD-416)
1. Viruses representative of circulating genotypes will be grown to high titers in eggs. 2. Amount of antigen to be used will be compared and standardized using a monoclonal antibody that recognizes a highly conserved epitope present in all viruses. 3. The antigen will be denatured using standard techniques and injected in 4 week SPF chickens to determine immune response and protection against NDV challenge. 4. Efficacy will be determined using high pathogenicity Newcastle disease virus in 4 week old SPF chicken with measurement of protection being prevention of morbidity and mortality, reduction in number of infected birds, and a decrease in the NDV-shed from respiratory and alimentary tracts. 5. Two antigens from genotype VI and VII will be compared to a mock vaccinated and to a standard vaccine based on a lentogenic virus and three different challenge viruses will be used (4x3 a total of 12 cages).
3. Progress Report
This research is related to inhouse objective 2: Development of improved Newcastle disease control strategies addressing issues important to virus transmission, vaccines and vaccination, diagnostics, or international trade. Develop models to show vaccination is a viable method of controlling avian paramyxovirus outbreaks. Experiments are currently underway to evaluate viruses from Peru, Malaysia and Mexico as antigens. Viruses have been grown to high titers, inactivated, and the antigen formulated as a live inactivated vaccine. Four week specific pathogen free chickens have been immunized and will be challenged to determine immune response and protection against Newcastle disease virus (NDV) challenge. Experiments were performed and protection against morbidity and mortality, reduction in number of infected birds, and a decrease in the NDV-shed from respiratory and alimentary tracts will be evaluated and compared to standard commercial vaccines.