Recombinant Newcastle Disease Virus (NDV) Expressing Sigma C Protein of Avian Reovirus (ARV) Protects against Both ARV and NDV in Chickens.

Deep Prakash Saikia,Ajai Lawrence D’Silva,Saravanan Ramakrishnan,Dinesh C Pathak,Asok Kumar Marriappan,Sohini Dey,Kalpana Yadav,Vikram N Vakharia,Madhan Mohan Chellappa,Narayan Ramamurthy

doi:10.3390/pathogens8030145

Deep Prakash Saikia, Ajai Lawrence D’Silva + Show 8 more

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https://doi.org/10.3390/pathogens8030145

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Abstract

Newcastle disease (ND) and avian reovirus (ARV) infections are a serious threat to the poultry industry, which causes heavy economic losses. The mesogenic NDV strain R2B is commonly used as a booster vaccine in many Asian countries to control the disease. In this seminal work, a recombinant NDV strain R2B expressing the sigma C (σC) gene of ARV (rNDV-R2B-σC) was generated by reverse genetics, characterized in vitro and tested as a bivalent vaccine candidate in chickens. The recombinant rNDV-R2B-σC virus was attenuated as compared to the parent rNDV-R2B virus as revealed by standard pathogenicity assays. The generated vaccine candidate, rNDV-R2B-σC, could induce both humoral and cell mediated immune responses in birds and gave complete protection against virulent NDV and ARV challenges. Post-challenge virus shedding analysis revealed a drastic reduction in NDV shed, as compared to unvaccinated birds.

Highlights

Viral arthritis/tenosynovitis is an economically important, widespread disease that affects the broiler breeders and flocks [1,2]
The σC gene cassette of 1.7 kb, containing the σC gene flanked by start and stop signals of Newcastle disease virus (NDV), was inserted between the non-coding regions of P and M genes of the viral genome to obtain plasmid pNDV-R2B-σC (Figure 1)
Sequence data of the rescued virus confirmed that the junctions of the NDV, for the σC gene in the transcription cassette, were intact confirming the recombinant nature of the virus generated by reverse genetics

Summary

Introduction

Viral arthritis/tenosynovitis is an economically important, widespread disease that affects the broiler breeders and flocks [1,2]. The disease is caused by avian reovirus (ARV), belonging to the Orthoreovirus genus of the family Reovirdae. Besides arthritis/tenosynovitis, the virus shows other clinical signs, causing gastroenteritis, hepatitis, myocarditis, malnutrition syndrome, chronic respiratory disease and affecting the central nervous system [3,4,5]. Avian reovirus is an icosahedral, non-enveloped virus consisting of ten segmented, double-stranded RNA genome. Based on their electrophoretic mobility, the ten segments comprise three each of L-class (L1, L2 and L3), M-class (M1, M2 and M3) segments, and four S-class segments (S1, S2, S3 and S4). The genome encodes eight structural proteins (λA, λB, λC, μA, μB, σA, σB and σC)

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