Non-structural protein NS3/NS3a is required for propagation of bluetongue virus in Culicoides sonorensis

Feenstra, Femke; Drolet, Barbara S.; Boonstra, J.; Rijn, Piet A. van

doi:10.1186/s13071-015-1063-3

Cited by 25 publications

(33 citation statements)

References 60 publications

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“…In addition, differences in tissue culture susceptibility observed between the three variants (and in comparison with BTV-25 and 26) raise questions pertaining to the nature of the viral genetic control(s) affecting transmission and susceptibility. Moreover, recent studies demonstrated that interactions between BT viral proteins are crucial in terms of tissue tropism and particularly in insect cells (Feenstra, Drolet, Boonstra, & van Rijn, 2015;Feenstra, van Gennip, Schreuder, & van Rijn, 2016;Nunes et al, 2014 andPullinger et al, 2016). Reverse genetics using mono-reassortants of BTV-26 genes in a BTV-1 background has been able to provide answers for some of these (Pullinger et al, 2016).…”

Section: Rt-qpcr Resultsmentioning

confidence: 99%

Bluetongue virus serotype 27: Experimental infection of goats, sheep and cattle with three BTV-27 variants reveal atypical characteristics and likely direct contact transmission BTV-27 between goats

Bréard

Schulz

Sailleau

et al. 2017

Transbound Emerg Dis

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Bluetongue virus (BTV) hitherto consisted of 26 recognized serotypes, of which all except BTV-26 are primarily transmitted by certain species of Culicoides biting midges. Three variants of an additional 27th bluetongue virus serotype (BTV-27v01-v03) were recently detected in asymptomatic goats in Corsica, France, 2014-2015. Molecular characterization revealed genetic differences between the three variants. Therefore, in vivo characteristics were investigated by experimental infection of a total of 15 goats, 11 sheep and 4 cattle with any one of the three variants in separated animal trials. In goat trials, BTV-naïve animals of the same species were kept in a facility where direct contact was unhindered. Of the 15 inoculated goats, 13 and 14 animals were found positive for BTV-RNA and antibodies (Ab), respectively, until the end of the experiments. Surprisingly, BTV-Ab levels as measured with ELISA and neutralization test (SNT) were remarkably low in all seropositive goats. Virus isolation from whole-blood was possible at the peak of viremia until 49 dpi. Moreover, detection of BTV-27v02-RNA and Ab in one contact goat indicated that-similar to BTV-26-at least one of three BTV-27 variants may be transmitted by contact between goats. In the field, BTV-27 RNA can be detected up to 6 months in the whole-blood of BTV-27-infected Corsican goats. In contrast, BTV RNA was not detected in the blood of cattle or sheep. In addition, BTV-27 Abs were not detected in cattle and only a transient increase in Ab levels was observed in some sheep. None of the 30 animals showed obvious BT-like clinical signs. In summary, the phenotypes observed for BTV-27v01-v03 phenotypes correspond to a mixture of characteristics known for BTV-25 and 26.

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Section: Rt-qpcr Resultsmentioning

confidence: 99%

Bluetongue virus serotype 27: Experimental infection of goats, sheep and cattle with three BTV-27 variants reveal atypical characteristics and likely direct contact transmission BTV-27 between goats

Bréard

Schulz

Sailleau

et al. 2017

Transbound Emerg Dis

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“…Current live attenuated BTV vaccines that are used in the field are not completely safe as some are linked with undesirable secondary reactions, such as teratogenic effects, reversion to virulence, and the risks of transmission to vectors. Vaccine studies with these DISA vaccines showed protection in vaccinated animals and inability to replicate in the Culicoides vector (25). The vaccine candidates that we are presenting in this report do not replicate either in cell culture or in the susceptible hosts and in that respect are more similar to an inactivated vaccine, but with several advantages.…”

Section: Discussionmentioning

confidence: 99%

Replication-Deficient Particles: New Insights into the Next Generation of Bluetongue Virus Vaccines

Celma

Stewart

Wernike

et al. 2017

J Virol

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Bluetongue virus (BTV) is endemic in many parts of the world, often causing severe hemorrhagic disease in livestock. To date, at least 27 different serotypes have been recognized. Vaccination against all serotypes is necessary to protect susceptible animals and to prevent onward spread of the virus by insect vectors. In our previous studies, we generated replication-deficient (disabled infectious single-cycle [DISC]) virus strains for a number of serotypes and reported preliminary data on their protective efficacy in animals. In this report, to advance the DISC vaccines to the marketplace, we investigated different parameters of these DISC vaccines. First, we demonstrated the genetic stabilities of these vaccine strains and also the complementing cell line. Subsequently, the optimal storage conditions of vaccines, including additives, temperature, and desiccation, were determined and their protective efficacies in animals confirmed. Furthermore, to test if mixtures of different vaccine strains could be tolerated, we tested cocktails of DISC vaccines in combinations of three or six different serotypes in sheep and cattle, the two natural hosts of BTV. Groups of sheep vaccinated with a cocktail of six different vaccines were completely protected from challenge with individual virulent serotypes, both in early challenge and after 5 months of challenge without any clinical disease. There was no interference in protection between the different vaccines. Protection was also achieved in cattle with a mixture of three vaccine strains, albeit at a lesser level than in sheep. Our data support and validate the suitability of these virus strains as the next-generation vaccines for BTV.IMPORTANCE Bluetongue (BT) is a debilitating and in many cases lethal disease that affects ruminants of economic importance. Classical vaccines that afford protection against bluetongue virus, the etiological agent, are not free from secondary and undesirable effects. A surge in new approaches to produce highly attenuated, safer vaccines was evident after the development of the BTV reverse-genetics system that allows the introduction of targeted mutations in the virus genome. We targeted an essential gene to develop disabled virus strains as vaccine candidates. The results presented in this report further substantiate our previous evidence and support the suitability of these virus strains as the next-generation BTV vaccines.

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“…Apparently, both are important for virus replication in vitro. Previously, it has been shown that NS3/NS3a is required for viraemia in sheep and virus propagation in Culicoides (Feenstra et al, 2014a(Feenstra et al, , 2015. Thus, NS3/NS3a is crucial in vivo for virus transmission between the insect vector and the ruminant host.…”

Section: Discussionmentioning

confidence: 99%

“…NS3/ NS3a is not essential for virus replication in vitro, although NS3/NS3a knockout BTV showed a disturbed release in mainly insect cells (van Gennip et al, 2014). However, NS3/NS3a is essential for viraemia in the mammalian host as well as for virus propagation in Culicoides vectors in vivo (Feenstra et al, 2014a(Feenstra et al, , 2015.…”

Section: Introductionmentioning

confidence: 99%

Balance of RNA sequence requirement and NS3/NS3a expression of segment 10 of orbiviruses

Feenstra

Gennip²,

Schreuder³

et al. 2016

Journal of General Virology

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Orbiviruses are insect-transmitted, non-enveloped viruses with a ten-segmented dsRNA genome of which the bluetongue virus (BTV) is the prototype. Viral non-structural protein NS3/NS3a is encoded by genome segment 10 (Seg-10), and is involved in different virus release mechanisms. This protein induces specific release via membrane disruptions and budding in both insect and mammalian cells, but also the cytopathogenic release that is only seen in mammalian cells. NS3/NS3a is not essential for virus replication in vitro with BTV Seg-10 containing RNA elements essential for virus replication, even if protein is not expressed. Recently, new BTV serotypes with distinct NS3/NS3a sequence and cell tropism have been identified. Multiple studies have hinted at the importance of Seg-10 in orbivirus replication, but the exact prerequisites are still unknown. Here, more insight is obtained with regard to the needs for orbivirus Seg-10 and the balance between protein expression and RNA elements. Multiple silent mutations in the BTV NS3a ORF destabilized Seg-10, resulting in deletions and sequences originating from other viral segments being inserted, indicating strong selection at the level of RNA during replication in mammalian cells in vitro. The NS3a ORFs of other orbiviruses were successfully exchanged in BTV1 Seg-10, resulting in viable chimeric viruses. NS3/NS3a proteins in these chimeric viruses were generally functional in mammalian cells, but not in insect cells. NS3/NS3a of the novel BTV serotypes 25 and 26 affected virus release from Culicoides cells, which might be one of the reasons for their distinct cell tropism.

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Non-structural protein NS3/NS3a is required for propagation of bluetongue virus in Culicoides sonorensis

Cited by 25 publications

References 60 publications

Bluetongue virus serotype 27: Experimental infection of goats, sheep and cattle with three BTV-27 variants reveal atypical characteristics and likely direct contact transmission BTV-27 between goats

Bluetongue virus serotype 27: Experimental infection of goats, sheep and cattle with three BTV-27 variants reveal atypical characteristics and likely direct contact transmission BTV-27 between goats

Replication-Deficient Particles: New Insights into the Next Generation of Bluetongue Virus Vaccines

Balance of RNA sequence requirement and NS3/NS3a expression of segment 10 of orbiviruses

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