|Peeters, Ben P.h.|
Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2003
Publication Date: 7/12/2003
Citation: Oldoni, I., Kommers, G.D., Wakamatsu, N., Brown, C.C., King, D.J., Peeters, B., Samal, S., Seal, B.S. 2003. Pathogenesis of various newcastle disease virus strains and recombinants in embryonated chicken eggs utilizing in situ hybridization and immunohistochemistry. American Society for Virology Meeting. Interpretive Summary:
Technical Abstract: Avian paramyxovirus type 1 (APMV-1), commonly referred to as Newcastle disease virus (NDV), is a member of the order Mononegalovirales in the family Paramyxoviridae and has been designated an Avulavirus. The primary molecular determinant for NDV virulence is the fusion (F) protein cleavage site amino acid sequence and the ability of specific cellular proteases to cleave the F protein of different pathotypes. Dibasic amino acids surrounding glutamine at position 114 are present in the F protein cleavage site of mesogenic or velogenic strains while lentogenic NDV isolates lack this motif. Six strains of Newcastle disease virus (NDV) representing all pathotypes and a rescued low-virulence NDV with an altered F protein cleavage site were inoculated into 9-day old chicken embryos. Tissues and chorioallantoic membranes (CAM) were harvested at 24-hour intervals post inoculation. In situ hybridization (ISH) using riboprobes specific for matrix protein genes and anti-peptide antibodies to the nucleoprotein highlighted distinct tissue tropisms among the viruses. The low-virulence lentogenic strains replicated exclusively in the epithelium of the CAM, whereas more virulent mesogenic and velogenic NDV isolates were widely disseminated in chicken embryo tissues. Tissues wherein virulent NDV could be detected included lung, muscle, skin, stomach and kidney. A rescued lentogenic NDV with a virulent F protein cleavage site was also examined. This virus did not replicate extensively in 4-week old chickens, but was detected in chicken embryo tissues similar to the more virulent isolates. Consequently, the F protein cleavage site is essential for virulence, but what other changes in NDV proteins contribute to virulence in adult chickens is unknown.