Generation by Reverse Genetics of an Effective, Stable, Live-Attenuated Newcastle Disease Virus Vaccine Based on a Currently Circulating, Highly Virulent Indonesian Strain

Abstract

Newcastle disease virus (NDV) can cause severe disease in chickens. Although NDV vaccines exist, there are frequent reports of outbreaks in vaccinated chickens. During 2009–2010, despite intense vaccination, NDV caused major outbreaks among commercial poultry farms in Indonesia. These outbreaks raised concern regarding the protective immunity of current vaccines against circulating virulent strains in Indonesia. In this study, we investigated whether a recombinant attenuated Indonesian NDV strain could provide better protection against prevalent Indonesian viruses. A reverse genetics system for the highly virulent NDV strain Banjarmasin/010/10 (Ban/010) isolated in Indonesia in 2010 was constructed. The Ban/010 virus is classified in genotype VII of class II NDV, which is genetically distinct from the commercial vaccine strains B1 and LaSota, which belong to genotype II, and shares only 89 and 87% amino acid identity for the protective antigens F and HN, respectively. A mutant virus, named Ban/AF, was developed in which the virulent F protein cleavage site motif “RRQKR↓F” was modified to an avirulent motif “GRQGR↓L” by three amino acid substitutions (underlined). The Ban/AF vaccine virus did not produce syncytia or plaques in cell culture, even in the presence of added protease. Pathogenicity tests showed that Ban/AF was completely avirulent. Ban/AF replicated efficiently during 10 consecutive passages in chickens and remained genetically stable. Serological analysis showed that Ban/AF induced higher neutralization and hemagglutination inhibition antibody titers against the prevalent viruses than the commercial vaccines B1 or LaSota. Both Ban/AF and commercial vaccines provided protection against clinical disease and mortality after challenge with virulent NDV strain Ban/010 (genotype VII) or GB Texas (genotype II). However, Ban/AF significantly reduced challenge virus shedding from the vaccinated birds compared to B1 vaccine. These results suggest that Ban/AF can provide better protection than commercial vaccines and is a promising vaccine candidate against NDV strains circulating in Indonesia.

Newcastle disease in Nigeria: epizootiology and current knowledge of circulating genotypes

“…The protection level of this vaccination schedule should be assessed with the circulating strains. In addition, the clamour for a genotype-matched vaccine has been in the news lately with several successes recorded using genotype VII [46,53,111]. It may therefore be imperative to develop a genotype-matched vaccine against the predominant genotype in West Africa to ameliorate the vaccination program.…”

Generation by reverse genetics of an effective attenuated Newcastle disease virus vaccine based on a prevalent highly virulent Chinese strain

“…1b). The protease cleavage site of the F0 protein was altered from 112 RRQKR;F 117 to the consensus sequence of the avirulent NDV strains, 112 GRQGR;L 117 (Xiao et al 2012). The fragment that contained the mutated F0 protein cleavage site was used to replace the corresponding fragment in the full-length cDNA of pOK-rSG10.…”

Past and Present of Reverse Genetics in Animal Virology with Special Reference to Non-Segmented Negative Stranded RNA Viruses: a Review

“…The recombinant strain KBNP-C4152R2L had a similar antigenicity as of KBNP-4152, but differed from wild type LaSota and it was completely avirulent with an ICPI of 0.00, making it a promising candidate for marker vaccine. Further, to strengthen the role of FPCS, a virulent genotype VII strain belonging to class II from Indonesia namely Banjarmasin/010/10 (Ban/010) was used as a candidate (Xiao et al, 2012) for development of live attenuated vaccine to protect the flocks against the circulating virulent genotype VII viruses. The experiment was carried out with the generation of an attenuated Ban/010 virus that was mutated in the FPCS region from virulent "RRQKR↓F" to avirulent "GRQGR↓L "by three amino acid substitutions, and the resultant recombinant virus has not reportedly produced any syncytia or plaques even after supplementing with an external protease, and was found to be completely avirulent.…”