Comparison of single 1-day-old chick vaccination using a Newcastle disease virus vector with a prime/boost vaccination scheme against a highly pathogenic avian influenza H5N1 challenge

Abstract

Avian influenza (AI) vaccines should be used as part of a whole comprehensive AI control programme. Vectored vaccines based on Newcastle disease virus (NDV) are very promising, but are so far licensed in only a few countries. In the present study, the immunogenicity and protection against a highly pathogenic H5N1 influenza challenge were evaluated after vaccination with an enterotropic NDV vector expressing an H5 haemagglutinin (rNDV-H5) in 1-day-old specific pathogen free chickens inoculated once, twice or once followed by a heterologous boost with an inactivated H5N9 vaccine (iH5N9). The heterologous prime/boost rNDV-H5/iH5N9 combination afforded the best level of protection against the H5N1 challenge performed at 6 weeks of age. Two rNDV-H5 administrations conferred a good level of protection after challenge, although only a cellular H5-specific response could be detected. Interestingly, a single administration of rNDV-H5 gave the same level of protection as the double administration but without any detectable H5-specific immune response. In contrast to AI immunity, a high humoral, mucosal and cellular NDV-specific immunity could be detected up to 6 weeks post vaccination after using the three different vaccination schedules. NDV-specific mucosal and cellular immune responses were slightly higher after double rNDV-H5 vaccination when compared with single inoculation. Finally, the heterologous prime/ boost rNDV-H5/iH5N9 combination induced a broader detectable immunity including systemic, mucosal and cellular AI and NDV-specific responses.

Viral vector-based influenza vaccines

“…148 Consequently, a recombinant NDV expressing HA genes of A(H5N1) viruses has been licensed as a poultry vaccine in some countries and was shown to have a protective effect against challenge infection with A(H5N1) viruses in chickens and ducks in various studies. [149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] The NDV based A(H5N1) vaccine offered only partial cross-clade protection, but was immunogenic in the presence of maternal antibodies. 162,163 Expression or coexpression of NA by NDV did not improve immunogenicity in chickens.…”

Prime-boost vaccination strategy against avian influenza and Newcastle disease viruses reduces shedding of the challenge viruses

“…Based on HI assay results, chickens in group (1), primed intraocularly with the mucosal-vaccine induced no or little ND-specific and AI-specific systemic antibodies. Similarly, other experiments reported that no AI-specific antibodies were induced after single intraocular immunization of chickens [9,10]. Meanwhile, after the second mucosal vaccination, Hikono et al [10] recorded a significant increase in serum antibody responses was detected 3 weeks' post-vaccination, same observation.…”

“…Newcastle disease virus (NDV) belongs to avian paramyxovirus type 1, which is a member of the genus Avulavirus of the Paramyxoviridae family [6,29]. NDV is as equally important as Avian Influenza, owing to its highly contagious nature and worldwide distribution; it is an economic burden [9,18]. Based on the severity of the disease symptoms, NDV strains have been classified as lentogenic (avirulent), mesogenic (intermediately virulent) and velogenic (virulent) [29].…”

Comparison of homologous and heterologous prime-boost immunizations combining MVA-vectored and plant-derived VP2 as a strategy against IBDV

“…Successful experiences with heterologous prime-boost also exist in the avian model: DNA prime-inactivated vaccine boost [28][29][30][31], DNA prime-protein boost [32], recombinant Fowlpox prime-inactivated vaccine boost [33] and recombinant Adenovirus prime-recombinant MVA boost [16] have all shown to be more immunogenic when compared to homologous schemes.…”