Efficacy in Chickens of a Herpesvirus of Turkeys Recombinant Vaccine Containing the Fusion Gene of Newcastle Disease Virus: Onset of Protection and Effect of Maternal Antibodies

Abstract

The onset of protection against Newcastle disease and the effect of maternal antibodies to Newcastle disease virus (NDV) and Marek's disease virus (MDV) on vaccine efficacy were determined following vaccination of chickens with a recombinant herpesvirus of turkeys (HVT) vaccine expressing the fusion (F) glycoprotein gene of NDV. Onset of protection following intra-abdominal administration of the recombinant HVT/F vaccine at 1 day of age and subsequent ocular challenge with the neurotropic velogenic Texas GB strain of NDV was determined to occur between days 14 and 21 post-vaccination (PV). Vaccination with the Hitchner B1 strain of NDV resulted in protection by day 6 PV, and vaccination with an inactivated NDV oil-emulsion vaccine induced protection by day 14 PV. One-day-old broiler-type chickens with maternal antibodies to both NDV and MDV and 1-day-old specific-pathogen-free (SPF) white leghorn chickens lacking maternal antibodies were vaccinated with the recombinant HVT/F vaccine or with control vaccines, challenged intra-abdominally with the very virulent RB1B strain of MDV on day 8 PV, and challenged with the Texas GB strain of NDV on day 29 PV. The HVT/F and NDV strain Hitchner B1 vaccines provided 73% and 80% protection, respectively, against NDV in broilers, whereas both vaccines resulted in 100% protection in SPF leghorns.

Development of an Effective Polyvalent Vaccine against both Marek's and Newcastle Diseases Based on Recombinant Marek's Disease Virus Type 1 in Commercial Chickens with Maternal Antibodies

“…In the poultry industry, four recombinant viruses (rFPV [1,5,8,14,18,25,31,34,35,59], rHVT [13,17,28,41,44,53], adenovirus [51], and rMDV1 [45,47,49,54,62]) that express foreign antigens of other avian pathogens (including NDV [14, 17, 24, 28-30, 35, 47, 53, 58], MDV [31,33,42,44,69], infectious bursal disease virus [1,5,13,18,19,51,62], avian influenza virus [2,3,5,56,59,61,65,66], avian leukosis virus [34], and avian reticuloendotheliosis virus [8]) have been developed, and these viruses showed significant vaccine efficacy against a variety of avian diseases. Further, rHVT, rMDV1, and rFPV expressing NDV antigens have been constructed and used to FIG.…”

“…rMDV1 showed almost 100% protective efficacy against NDV and MDV1 challenge in specific-pathogen-free (SPF) chickens lacking maternal antibodies from ND and MD by one-time inoculation, whereas the protective efficacy varied among experiments and decreased on average to 70% in chickens with maternal antibodies even though the challenge experiments were performed at a time when the maternal antibodies would not affect an evaluation of the protective efficacy. In the other systems using rHVT expressing NDV-F under the control of a strong promoter from the Rous sarcoma virus long terminal repeat and several recombinant fowl poxviruses (rFPV) expressing the NDV-F or hemagglutinin-neuraminidase gene, a similar problem with the maternal antibodies was also reported (14,25,28,29,35,57,58). Although it is not known why the recombinant polyvalent vaccines are not completely effective against the avian diseases in the presence of maternal antibodies, it is conceivable that the strong expression of these foreign genes induces a strong host immune reaction against the recombinant vaccines, which results in inhibition of the growth of the recombinant viruses in chickens.…”

“…Previously reported recombinant vaccines which express NDV-F protein generally provided systemic protection but very poor local protection (28). To see whether vaccination of commercial chickens with rMDV1-US10P(F) induces local immunity against NDV, commercial chickens were mock immunized or immunized with rMDV1-US10P(F).…”

“…(i) The viruses induce lifetime protection against MD with just one vaccination (39), (ii) the viruses have a natural host range limited to avian species, and therefore, the vectors would be safe for other domestic animals and people working in the poultry industry, and (iii) techniques for generating recombinant MDVs have been well established (45,49). Among the vaccine viruses, HVT has been used worldwide both as live vaccine and polyvalent vaccine vector (13,17,28,29,41,42,53). However, attenuated MDV1 strains, such as C/R6 (G. F. de Boer, J. M. A. Pol, and S. H. M. Jeurissen, Proc.…”

Recombinant Viral Vector Vaccines for the Veterinary Use.

“…Some groups showed that HVT can be used as a viral vector for expression of antigen from other avian pathogens [20,73,74,98,103]. The recombinant HVT, expressing the fusion (F) antigen of Newcastle disease virus (NDV), protected chickens against challenge infection with virulent NDV and retained the capacity of HVT to protect against Marek's disease [73].…”