Submitted to: Veterinary Pathology
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2004
Publication Date: 11/10/2004
Citation: Wakamatsu, N., King, D.J., Seal, B.S., Peeters, B.P., Samal, S.K., Brown, C.C. 2004. Pathogenesis of newcastle disease virus, using infectious clones to examine contributions of various genes to virulence [abstract]. Veterinary Pathology. 41(5):573. Interpretive Summary:
Technical Abstract: Infectious clones of Newcastle disease virus (NDV) were utilized to evaluate relative contributions of the fusion (F) protein, hemagglutinin-neuraminidase (HN) protein, and phosphoprotein (P) to virulence. Specifically, two different clones of the La Sota virus backbone with a F cleavage site mutated to virulent motif, virulent Beaudette C backbone with avirulent La Sota HN, and a virulent Beaudette C backbone with mutations in P were examined. Four-week-old White Leghorn chickens were inoculated with viruses, and tissues collected at intervals were examined by histology, immunohistochemistry, and/or in situ hybridization. Birds inoculated with recombinant La Sota with virulent F had histologic lesions and viral distribution that were greater than the lentogenic parent yet markedly less than the wild type virulent virus. Birds infected with an infectious clone of virulent Beaudette C exhibited marked histological lesions, and virus was distributed in numerous organs. Birds inoculated with recombinant Beaudette C chimera containing a La Sota HN displayed minimal histological lesions and virus distribution was limited. Birds inoculated with the Beaudette C clones with mutated P displayed reduced virulence with virus primarily restricted to inoculation sites. These preliminary findings indicate that presence of a virulent F within a lentogenic background moderately increases histological damage and viral distribution. However, the change is still reduced relative to virulent NDV. Conversely, substituting an avirulent HN into a virulent backbone greatly decreases virulence. Additionally, modifying the P within a virulent virus causes a decrease in severity of histological lesions and viral distribution.