title: Immunization of chickens with Newcastle disease virus expressing H5 hemagglutinin protects against highly pathogenic H5N1 avian influenza viruses.
abstract: BACKGROUND
  Highly-pathogenic avian influenza virus (HPAIV) and Newcastle disease virus (NDV) are the two most important poultry viruses in the world. Natural low-virulence NDV strains have been used as vaccines over the past 70 years with proven track records. We have previously developed a reverse genetics system to produce low-virulent NDV vaccine strain LaSota from cloned cDNA. This system allows us to use NDV as a vaccine vector for other avian pathogens.
  
  
  RESULTS
  Here, we constructed two recombinant NDVs (rNDVs) each of which expresses the hemagglutinin (HA) gene of HPAIV H5N1 strain A/Vietnam/1203/2004 from an added gene. In one, rNDV (rNDV-HA), the open reading frame (ORF) of HA gene was expressed without modification. In the second, rNDV (rNDV-HAF), the ORF was modified so that the transmembrane and cytoplasmic domains of the encoded HA gene were replaced with those of the NDV F protein. The insertion of either version of the HA ORF did not increase the virulence of the rNDV vector. The HA protein was found to be incorporated into the envelopes of both rNDV-HA and rNDV-HAF. However, there was an enhanced incorporation of the HA protein in rNDV-HAF. Chickens immunized with a single dose of either rNDV-HA or rNDV-HAF induced a high titer of HPAIV H5-specific antibodies and were completely protected against challenge with NDV as well as lethal challenges of both homologous and heterologous HPAIV H5N1.
  
  
  CONCLUSIONS
  Our results suggest that these chimeric viruses have potential as safe and effective bivalent vaccines against NDV and. HPAIV. These vaccines will be convenient and affordable, which will be highly beneficial to the poultry industry. Furthermore, immunization with these vaccines will permit serological differentiation of vaccinated and avian influenza field virus infected animals.
authors: Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America.
authors: Baibaswata
authors: B
authors: Nayak
authors: Subrat N
authors: SN
authors: Rout
authors: Sachin
authors: S
authors: Kumar
authors: Mohammed S
authors: MS
authors: Khalil
authors: Moustafa M
authors: MM
authors: Fouda
authors: Luay E
authors: LE
authors: Ahmed
authors: Kenneth C
authors: KC
authors: Earhart
authors: Daniel R
authors: DR
authors: Perez
authors: Peter L
authors: PL
authors: Collins
authors: Siba K
authors: SK
authors: Samal
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D002645:Chickens; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology* / Q000472:pathogenicity; D016253:Microscopy, Immunoelectron; D009522:Newcastle disease virus / Q000276:immunology*; D014774:Virulence
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus