Development of a recombinant Newcastle disease virus-vectored vaccine for infectious bronchitis virus variant strains circulating in Egypt

Vet Res. 2019 Feb 11;50(1):12. doi: 10.1186/s13567-019-0631-5.

Abstract

Infectious bronchitis virus (IBV) causes a major disease problem for the poultry industry worldwide. The currently used live-attenuated vaccines have the tendency to mutate and/or recombine with circulating field strains resulting in the emergence of vaccine-derived variant viruses. In order to circumvent these issues, and to develop a vaccine that is more relevant to Egypt and its neighboring countries, a recombinant avirulent Newcastle disease virus (rNDV) strain LaSota was constructed to express the codon-optimized S glycoprotein of the Egyptian IBV variant strain IBV/Ck/EG/CU/4/2014 belonging to GI-23 lineage, that is prevalent in Egypt and in the Middle East. A wild type and two modified versions of the IBV S protein were expressed individually by rNDV. A high level of S protein expression was detected in vitro by Western blot and immunofluorescence analyses. All rNDV-vectored IBV vaccine candidates were genetically stable, slightly attenuated and showed growth patterns comparable to that of parental rLaSota virus. Single-dose vaccination of 1-day-old SPF White Leghorn chicks with the rNDVs expressing IBV S protein provided significant protection against clinical disease after IBV challenge but did not show reduction in tracheal viral shedding. Single-dose vaccination also provided complete protection against virulent NDV challenge. However, prime-boost vaccination using rNDV expressing the wild type IBV S protein provided better protection, after IBV challenge, against clinical signs and significantly reduced tracheal viral shedding. These results indicate that the NDV-vectored IBV vaccines are promising bivalent vaccine candidates to control both infectious bronchitis and Newcastle disease in Egypt.

MeSH terms

  • Animals
  • Cell Line
  • Chickens*
  • Coronavirus Infections / prevention & control
  • Coronavirus Infections / veterinary*
  • Egypt
  • Genetic Vectors / immunology
  • Infectious bronchitis virus / genetics
  • Infectious bronchitis virus / immunology*
  • Newcastle disease virus / genetics
  • Newcastle disease virus / immunology*
  • Poultry Diseases / prevention & control*
  • Spike Glycoprotein, Coronavirus / genetics
  • Spike Glycoprotein, Coronavirus / immunology*
  • Vaccines, Synthetic / administration & dosage
  • Vaccines, Synthetic / genetics
  • Vaccines, Synthetic / immunology
  • Viral Vaccines / administration & dosage
  • Viral Vaccines / genetics
  • Viral Vaccines / immunology*

Substances

  • Spike Glycoprotein, Coronavirus
  • Vaccines, Synthetic
  • Viral Vaccines
  • spike protein, avian infectious bronchitis virus