Publications

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

There were a total of 2599 results for your search.
Paladino LZC, Wilson R, Tng PYL, Dhokiya V, Keen E, Cuber P, Larner W, Rooney S, Nicholls M, Uglow A, Williams L, Anderson MAE, Basu S, Leftwich PT, Alphey L (2023)

Optimizing CRE and PhiC31 mediated recombination in Aedes aegypti

Frontiers in Bioengineering and Biotechnology 11

Abstract

Introduction: Genetic manipulation of Aedes aegypti is key to developing a deeper understanding of this insects’ biology, vector-virus interactions and makes future genetic control strategies possible. Despite some advances, this process remains laborious and requires highly skilled researchers and specialist equipment.

Methods: Here we present two improved methods for genetic manipulation in this species. Use of transgenic lines which express Cre recombinase and a plasmid-based method for expressing PhiC31 when injected into early embryos.

Results: Use of transgenic lines which express Cre recombinase allowed, by simple crossing schemes, germline or somatic recombination of transgenes, which could be utilized for numerous genetic manipulations. PhiC31 integrase based methods for site-specific integration of genetic elements was also improved, by developing a plasmid which expresses PhiC31 when injected into early embryos, eliminating the need to use costly and unstable mRNA as is the current standard.

Discussion: Here we have expanded the toolbox for synthetic biology in Ae. aegypti. These methods can be easily transferred into other mosquito and even insect species by identifying appropriate promoter sequences. This advances the ability to manipulate these insects for fundamental studies, and for more applied approaches for pest control.

Abstract

Nairobi sheep disease (NSD), caused by the viral agent NSD virus (NSDV), is a haemorrhagic fever disease affecting and inducing high mortality in sheep and goat populations. NSDV belongs to the genus Orthonairovirus of the Nairoviridae family from the order Bunyavirales. Other viruses circulating in livestock such as Crimean–Congo haemorrhagic fever virus (CCHFV) and Dugbe virus (DUGV) are members of the same genus and are reported to share antigenic features. There are very few available materials to study NSDV infection both in vitro and in vivo. In the present work, we characterised two monoclonal antibodies generated in mice that recognise NSDV specifically but not CCHFV or DUGV, along with a potential use to define virus-infected cells, using flow cytometry. We believe this tool can be useful for research, but also NSDV diagnostics, especially through immunological staining.

Tully M, Batten C, Ashby M, Mahapatra M, Parekh K, Parida S, Njeumi F, Willett B, Bataille A, Libeau G, Kwiatek O, Caron A, Berguido FJ, Lamien CE, Cattoli G, Misinzo G, Keyyu J, Mdetele D, Gakuya F, Bodjo SC, Taha FA, Elbashier HM, Khalafalla AI, Osman AY, Kock R (2023)

The evaluation of five serological assays in determining seroconversion to peste des petits ruminants virus in typical and atypical hosts

scientific reports 13, 14787

Abstract

Peste des petits ruminants (PPR) is an infectious viral disease, primarily of small ruminants such as sheep and goats, but is also known to infect a wide range of wild and domestic Artiodactyls including African buffalo, gazelle, saiga and camels. The livestock-wildlife interface, where free-ranging animals can interact with captive flocks, is the subject of scrutiny as its role in the maintenance and spread of PPR virus (PPRV) is poorly understood. As seroconversion to PPRV indicates previous infection and/or vaccination, the availability of validated serological tools for use in both typical (sheep and goat) and atypical species is essential to support future disease surveillance and control strategies. The virus neutralisation test (VNT) and enzyme-linked immunosorbent assay (ELISA) have been validated using sera from typical host species. Still, the performance of these assays in detecting antibodies from atypical species remains unclear. We examined a large panel of sera (n = 793) from a range of species from multiple countries (sourced 2015–2022) using three tests: VNT, ID VET N-ELISA and AU-PANVAC H-ELISA. A sub-panel (n = 30) was also distributed to two laboratories and tested using the luciferase immunoprecipitation system (LIPS) and a pseudotyped virus neutralisation assay (PVNA). We demonstrate a 75.0–88.0% agreement of positive results for detecting PPRV antibodies in sera from typical species between the VNT and commercial ELISAs, however this decreased to 44.4–62.3% in sera from atypical species, with an inter-species variation. The LIPS and PVNA strongly correlate with the VNT and ELISAs for typical species but vary when testing sera from atypical species.

Abstract

Current legislation in the United Kingdom stipulates that horses should not be slaughtered within sight of one another. However, abattoir personnel anecdotally report that, for semi-feral horses unused to restraint, co-slaughtering alongside a conspecific could reduce distress through social buffering and improve safety, but there is a lack of evidence to support this. CCTV footage from an English abattoir was assessed retrospectively with welfare indicators from when horses entered the kill pen until they were killed. Of 256 horses analysed, 12% (32/256) were co-slaughtered (alongside a conspecific) and 88% (224/256) individually. Co-slaughtered horses moved more in the pen, but individually slaughtered horses showed more agitated behaviour, required more encouragement to enter the kill pen, and experienced more slips or falls. Unrestrained horses (40%; 102/256) showed increased agitation, movement, and agonistic behaviour towards the operator and resisted entry to the kill pen compared to restrained horses (60%; 154/256). Positive interactions between conspecifics were seen in 94% (30/32) of co-slaughtered horses, and only 6% (1/16) showed a startled response to the first horse being shot, with a median time of 15 s between shots. This study highlights the impact that both conspecific and human interactions can have on equine welfare at slaughter. Semi-feral or unrestrained horses appear to experience increased distress compared to horses more familiar with human handling, and the presence of a conspecific at slaughter mitigated this.

Gonzales BL, Andrade DA, Valdivia, CA, Ho-Palma AC, Munguia A, Yucra D, Escobedo M, Crotta M, Limon G, Gonzalez A, Guitian J, Gonzales-Gustavson, E (2023)

Detection and Isolation of Escherichia coli O157:H7 in Beef from Food Markets and Fecal Samples of Dairy Calves in the Peruvian Central Highlands

The American Journal of Tropical Medicine and Hygiene 109 (3), 568-570

Abstract

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is a food and waterborne pathogen with severe public health implications. We report the first-time isolation of this pathogen in the Central Highlands of Peru through standardized culture procedures and polymerase chain reaction (PCR). Escherichia coli strains were cultured from rectal-anal swabs from dairy calves and beef from food markets. The latex agglutination test was used to detect O157 and H7 antigens, and multiplex real-time PCR was carried out to detect virulence-related genes. The STEC O157:H7 strains were isolated from 3.5% (1/28) of beef samples and from 6.0% (3/50) of dairy calves that also carried both eaeA and stx1 genes. Therefore, this pathogen is a potential cause of food/waterborne disease in the region, and its surveillance in both livestock and their products should be improved to characterize the impact of its zoonotic transmission. From 2010 to 2020, E. coli was suspected in 10 outbreaks reported to the Peruvian Ministry of Health. Isolates from future outbreaks should be characterized to assess the burden posed by STEC O157:H7 in Peru.

Abstract

Type I interferons (IFN) are the first line of immune response against infection. In this study, we explore the interaction between Type I IFN and foot-and-mouth disease virus (FMDV), focusing on the effect of this interaction on epithelial cell death. While several mathematical models have explored the interaction between interferon and viruses at a systemic level, with most of the work undertaken on influenza and hepatitis C, these cannot investigate why a virus such as FMDV causes extensive cell death in some epithelial tissues leading to the development of lesions, while other infected epithelial tissues exhibit negligible cell death. Our study shows how a model that includes epithelial tissue structure can explain the development of lesions in some tissues and their absence in others. Furthermore, we show how the site of viral entry in an epithelial tissue, the viral replication rate, IFN production, suppression of viral replication by IFN and IFN release by live cells, all have a major impact on results.

Abstract

Cattle, sheep, and goats are the only species outside primates known to have an expanded and diversified family of killer immunoglobulin-like receptors (KIR). Primate KIR are expressed on the surface of NK and T cells and bind MHC-I to control activation. However, the surface expression, ligands and function of bovid KIR remain unknown. Cattle botaKIR2DL1 is the only functional KIR of the same DL-lineage as the expanded KIR in primates and we examined if leukocyte expression patterns were consistent with human. We raised a specific mouse anti-botaKIR2DL1 monoclonal antibody and assessed its utility in flow cytometry, ELISA, and western blot. Unlike primates, cattle DL-lineage KIR (botaKIR2DL1) is present on B cells and monocytes in addition to T cells and low-level expression on NK cells. Expression decreases after in vitro PBMC stimulation with IL-2. This suggests that botaKIR2DL1 has different functions, and potentially ligands, compared to primate KIR.

Abstract

Viral replication fully relies on the host cell machinery, and physical interactions between viral and host proteins mediate key steps of the viral life cycle. Therefore, identifying virus-host protein-protein interactions (PPIs) provides insights into the molecular mechanisms governing virus infection and is crucial for designing novel antiviral strategies. In the case of the African swine fever virus (ASFV), a large DNA virus that causes a deadly panzootic disease in pigs, the limited understanding of host and viral targets hinders the development of effective vaccines and treatments. This review summarizes the current knowledge of virus-host and virus-virus PPIs by collecting and analyzing studies of individual viral proteins. We have compiled a dataset of experimentally determined host and virus protein targets, the molecular mechanisms involved, and the biological functions of the identified virus-host and virus-virus protein interactions during infection. Ultimately, this work provides a comprehensive and systematic overview of ASFV interactome, identifies knowledge gaps, and proposes future research directions.

Abstract

Marek's disease virus (MDV) causes a deadly lymphoproliferative disease in chickens, resulting in huge economic losses in the poultry industry. It has been suggested that MDV suppresses the induction of type I interferons and thus escapes immune control. Cholesterol 25-hydroxylase (CH25H), a gene that encodes an enzyme that catalyses cholesterol to 25-hydroxycholesterol (25-HC), is an interferon-stimulating gene (ISG) known to exert antiviral activities. Other oxysterols, such as 27-hydroxycholesterols (27-HC), have also been shown to exert antiviral activities, and 27-HC is synthesised by the catalysis of cholesterol via the cytochrome P450 enzyme oxidase sterol 27-hydroxylase A1 (CYP27A1). At 24 h post infection (hpi), MDV stimulated a type I interferon (IFN-α) response, which was significantly reduced at 48 and 72 hpi, as detected using the luciferase assay for chicken type I IFNs. Then, using RT-PCR, we demonstrated that chicken type I IFN (IFN-α) upregulates chicken CH25H and CYP27A1 genes in chicken embryo fibroblast (CEF) cells. In parallel, our results demonstrate a moderate and transient upregulation of CH25H at 48 hpi and CYP27A1 at 72hpi in MDV-infected CEF cells. A significant reduction in MDV titer and plaque sizes was observed in CEFs treated with 25-HC or 27-HC in vitro, as demonstrated using a standard plaque assay for MDV. Taken together, our results suggest that 25-HC and 27-HC may be useful antiviral agents to control MDV replication and spread.

Abstract

African swine fever virus (ASFV) is known to be very stable and can remain infectious over long periods of time especially at low temperatures and within different matrices, particularly those containing animal-derived organic material. However, there are some gaps in our knowledge pertaining to the survivability and infectivity of ASFV in groundwater. This study aims to determine the stability and infectivity of the cell culture-adapted ASFV strain BA71V by plaque assay after incubation of the virus within river water samples at three different environmentally relevant temperatures (4 °C, 15 °C, and 21 °C) over the course of 42 days. The results from this study indicate that ASFV can remain stable and infectious when maintained at 4 °C in river water for more than 42 days, but as incubation temperatures are increased, the stability is reduced, and the virus is no longer able to form plaques after 28 days and 14 days, respectively, when stored at 15 °C and 21 °C. Characterizing the survivability of ASFV in groundwater can allow us to develop more appropriate inactivation and disinfection methods to support disease control and mitigate ASFV outbreaks.

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