Publications

The Pirbright Institute publication directory contains details of selected publications written by our researchers.

There were a total of 2120 results for your search.

Abstract

Using the best animal models to study immune responses against specific pathogens or vaccines can dramatically accelerate our understanding. Veterinary species are well studied, particularly livestock, to reduce their disease burden. They have also proven to be powerful models, especially for zoonotic pathogens and novel vaccination strategies. A prerequisite for any model selection is having the right quality and range of species?specific immunological reagents. To help promote the widest possible use of veterinary species, an open access website (https://www.immunologicaltoolbox.co.uk) has been created as a central community annotated hub for veterinary immunological reagents. The website is also the portal into services offered by the UK Immunological Toolbox project that includes antibody generation, sequencing and recombinant expression. The funding for this effort is linked into sustainable sources but ultimate success still relies on community engagement to continually increase the quality and quantity of information. It is hoped that as more users and reagent owners engage it will become an essential resource for researchers, veterinarians and clinicians alike by removing barriers that prevent the use of the most informative animal models.

Flannery J, Frost L, Fay P, Hicks H, Henstock M, Smreczak M, Orłowska A, Rajko-Nenow P, Darpel K, Batten C (2020)

BTV-14 infection in sheep elicits viraemia with mild clinical symptoms

Microorganisms 8 (6), 892

Abstract

In 2011, Bluetongue virus serotype 14 (BTV-14) was detected in Russia during routine surveillance, and was subsequently found in a number of European countries. The strain had high sequence similarity to a BTV-14 vaccine strain. We aimed to determine the risk of this BTV-14 strain causing disease in a UK sheep breed. Four Poll Dorset sheep were infected with a Polish isolate of BTV-14 and infection kinetics were monitored over 28 days. BTV RNA was detected in EDTA blood by 4 days post-infection (dpi) and remained detectable at 28 days post-infection (dpi). Peak viraemia occurred at 6 and 7 dpi with Ct values ranging between 24.6 and 27.3 in all infected animals. BTV antibodies were detected by 10 dpi using a commercial ELISA and neutralising antibodies were detected from 10 dpi. BTV was isolated between 6 and 12 dpi. All infected sheep developed mild clinical signs such as reddening of conjunctiva and mucosal membranes, with one sheep demonstrating more overt clinical signs. Two uninoculated control animals remained clinically healthy and did not have detectable BTV RNA or antibodies. The overall mild clinical symptoms caused by this BTV-14 in this highly susceptible sheep breed were in accordance with the asymptomatic infections observed in the affected countries.

Abstract

IBDV is economically important to the poultry industry. Very virulent (vv) strains cause higher mortality rates than other strains for reasons that remain poorly understood. In order to provide more information on IBDV disease outcome, groups of chickens (n = 18) were inoculated with the vv strain, UK661, or the classical strain, F52/70. Birds infected with UK661 had a lower survival rate (50%) compared to F52/70 (80%). There was no difference in peak viral replication in the bursa of Fabricius (BF), but the expression of chicken IFNα, IFNβ, MX1, and IL-8 was significantly lower in the BF of birds infected with UK661 compared to F52/70 (p < 0.05) as quantified by RTqPCR, and this trend was also observed in DT40 cells infected with UK661 or F52/70 (p < 0.05). The induction of expression of type I IFN in DF-1 cells stimulated with polyI:C (measured by an IFN-β luciferase reporter assay) was significantly reduced in cells expressing ectopic VP4 from UK661 (p < 0.05), but was higher in cells expressing ectopic VP4 from F52/70. Cells infected with a chimeric recombinant IBDV carrying the UK661-VP4 gene in the background of PBG98, an attenuated vaccine strain that induces high levels of innate responses (PBG98-VP4UK661) also showed a reduced level of IFNα and IL-8 compared to cells infected with a chimeric virus carrying the F52/70-VP4 gene (PBG98-VP4F52/70) (p < 0.01), and birds infected with PBG98-VP4UK661 also had a reduced expression of IFNα in the BF compared to birds infected with PBG98-VP4F52/70 (p < 0.05). Taken together, these data demonstrate that UK661 induced the expression of lower levels of anti-viral type I IFN and proinflammatory genes than the classical strain in vitro and in vivo and this was, in part, due to strain-dependent differences in the VP4 protein.

Abstract

Bluetongue virus (BTV) causes an economically important disease, bluetongue (BT), in susceptible ruminants and is transmitted primarily by species of Culicoides biting midges (Diptera: Ceratopogonidae). Since 2006, northern Europe has experienced multiple incursions of BTV through a variety of routes of entry, including major outbreaks of strains of BTV serotype 8 (BTV-8) and BTV serotype 1 (BTV-1), which overlapped in distribution within southern Europe. In this paper, we examined the variation in response to coinfection with strains of BTV-1 and BTV-8 using an in vivo transmission model involving Culicoides sonorensis, low passage virus strains, and sheep sourced in the United Kingdom. In the study, four sheep were simultaneously infected using BTV-8 and BTV-1 intrathoracically inoculated C. sonorensis and co-infections of all sheep with both strains were established. However, there were significant variations in both the initiation and peak levels of virus RNA detected throughout the experiment, as well as in the infection rates in the C. sonorensis that were blood-fed on experimentally infected sheep at peak viremia. This is discussed in relation to the potential for reassortment between these strains in the field and the policy implications for detection of BTV strains.

Abstract

Background: The recent reclassification of formaldehyde as a presumed carcinogen prompted the investigation into the comparative efficacy of hydrogen peroxide as a fumigant in microbiological safety cabinets.

Introduction: The aim of the study was to quantify the biocidal efficacy of formaldehyde fumigation, including variables such as exposure time and concentration, and then to compare this to the biocidal efficacy achieved from a hydrogen peroxide vapor fumigation system. The study also investigated the ability of both fumigants to permeate the microbiological safety cabinet (MBSC), including the workspace, under the work tray, and after the HEPA filters. Furthermore, the effect of organic soiling on efficacy was also assessed. Infectious bronchitis virus (IBV) was used as the biological target to develop this study model.

Methods: A model using IBV was developed to determine the efficacy of formaldehyde and hydrogen peroxide as fumigants. Virus was dried on stainless steel discs, and variables including concentration, time, protein soiling, and location within an MBSC were assessed.

Results: It was demonstrated that formaldehyde fumigation could achieve a 6-log reduction in the titer of the virus throughout the cabinet, and high protein soiling in the presentation did not affect efficacy. Appropriate cycle parameters for the hydrogen peroxide system were developed, and when challenged with IBV, it was shown that vaporized hydrogen peroxide could achieve an equal 6-log titer reduction as formaldehyde within the cabinet workspace and overcome the presence of soiling.

Conclusion: Hydrogen peroxide was demonstrated to be a viable alternative to formaldehyde under most situations tested. However, the hydrogen peroxide system did not achieve an equal titer reduction above the cabinet’s first HEPA filter using the cabinet workspace cycle, and further optimization of the hydrogen peroxide cycle parameters, including pulsing of the cabinet fans, may be required to achieve this.

Abstract

Zoonotic coronavirus (CoV) infections, such as those responsible for the current severe acute respiratory syndrome-CoV 2 (SARS-CoV-2) pandemic, cause grave international public health concern. In infected cells, the CoV RNA-synthesizing machinery associates with modified endoplasmic reticulum membranes that are transformed into the viral replication organelle (RO). Although double-membrane vesicles (DMVs) appear to be a pan-CoV RO element, studies to date describe an assortment of additional CoV-induced membrane structures. Despite much speculation, it remains unclear which RO element(s) accommodate viral RNA synthesis. Here we provide detailed 2D and 3D analyses of CoV ROs and show that diverse CoVs essentially induce the same membrane modifications, including the small open double-membrane spherules (DMSs) previously thought to be restricted to gamma- and delta-CoV infections and proposed as sites of replication. Metabolic labeling of newly synthesized viral RNA followed by quantitative electron microscopy (EM) autoradiography revealed abundant viral RNA synthesis associated with DMVs in cells infected with the beta-CoVs Middle East respiratory syndrome-CoV (MERS-CoV) and SARS-CoV and the gamma-CoV infectious bronchitis virus. RNA synthesis could not be linked to DMSs or any other cellular or virus-induced structure. Our results provide a unifying model of the CoV RO and clearly establish DMVs as the central hub for viral RNA synthesis and a potential drug target in CoV infection.

Abstract

Various viruses have evolved a plethora of strategies to manipulate DNA damage machinery and commandeer cells to maximize their own replication. On the contrary, host cells have also evolved to maintain cellular genomic stability and suppress carcinogenesis through multifaceted cellular DNA damage response (DDR). Most studies have focused on the relationship between DNA virus replication and the host DDR pathway, but few have investigated the interface between the DDR pathway and ribonucleic acid (RNA) viruses, such as oncolytic Newcastle disease virus (NDV). In the present study, we report for the first time that F-HN co-expression and NDV infection trigger ataxia telangiectasia-mutated (ATM)-dependent DSB lesions in tumor cells to promote viral replication and syncytium formation, respectively. We found that late NDV infection and membrane fusion activated the ATM-Chk2 axis in tumor cells, which expands prior understanding of the membrane fusion process and NDV infection. Our findings reveal new links among oncolytic NDV replication, membrane fusion, and DDR and deepen insights into NDV replication.

Abstract

Live attenuated vaccines are considered to be the fastest route to the development of a safe and efficacious African swine fever (ASF) vaccine. Infection with the naturally attenuated OURT88/3 strain induces protection against challenge with virulent isolates from the same or closely related genotypes. However, adverse clinical signs following immunisation have been observed. Here, we attempted to increase the OURT88/3 safety profile by deleting I329L, a gene previously shown to inhibit the host innate immune response. The resulting virus, OURT88/3ΔI329L, was tested in vitro to evaluate the replication and expression of type I interferon (IFN) and in vivo by immunisation and lethal challenge experiments in pigs. No differences were observed regarding replication; however, increased amounts of both IFN-β and IFN-α were observed in macrophages infected with the deletion mutant virus. Unexpectedly, the deletion of I329L markedly reduced protection against challenge with the virulent OURT88/1 isolate. This was associated with a decrease in both antibody levels against VP72 and the number of IFN-γ-producing cells in the blood of non-protected animals. Furthermore, a significant increase in IL-10 levels in serum was observed in pigs immunised with OURT88/3ΔI329L following challenge. Interestingly, the deletion of the I329L gene failed to attenuate the virulent Georgia/2007 isolate.

Abstract

The main target cells for African swine fever virus (ASFV) replication in pigs are of monocyte macrophage lineage and express markers typical of the intermediate to late stages of differentiation. The lack of a porcine cell line, which accurately represents these target cells, limits research on virus host interactions and the development of live-attenuated vaccine strains. We show here that the continuously growing, growth factor dependent ZMAC-4 porcine macrophage cell line is susceptible to infection with eight different field isolates of ASFV. Replication in ZMAC-4 cells occurred with similar kinetics and to similar high titres as in primary porcine bone marrow cells. In addition we showed that twelve passages of an attenuated strain of ASFV, OURT88/3, in ZMAC-4 cells did not reduce the ability of this virus to induce protection against challenge with virulent virus. Thus, the ZMAC-4 cells provide an alternative to primary cells for ASFV replication.

Abstract

Receptor recognition and binding is the first step of viral infection and a key determinant of host specificity. The inability of avian influenza viruses to effectively bind human-like sialylated receptors is a major impediment to their efficient transmission in humans and pandemic capacity. Influenza H9N2 viruses are endemic in poultry across Asia and parts of Africa where they occasionally infect humans and are therefore considered viruses with zoonotic potential. We previously described H9N2 viruses, including several isolated from human zoonotic cases, showing a preference for human-like receptors. Here we take a mutagenesis approach, making viruses with single or multiple substitutions in H9 haemagglutinin to determine the genetic basis of preferences for alternative avian receptors and for human-like receptors. We describe amino acid motifs at positions 190, 226 and 227 that play a major role in determining receptor specificity, and several other residues such as 159, 188, 193, 196, 198 and 225 play a smaller role. Furthermore, we show changes at residues 135, 137, 147, 157, 158, 184, 188, and 192 can also modulate virus receptor avidity and that substitutions that increased or decreased the net positive charge around the haemagglutinin receptor-binding site show increases and decreases in avidity, respectively. The motifs we identify as increasing preference for the human-receptor will help guide future H9N2 surveillance efforts and facilitate our understanding of the emergence of influenza viruses with high zoonotic potential.

Pages

Filter Publications

Trim content

® The Pirbright Institute 2020 | A company limited by guarantee, registered in England no. 559784. The Institute is also a registered charity.