Notable Recent Publications
These are some recent publications which give a flavour of the research from the Barclay lab. For a complete list of publications, please see below.
Species difference in ANP32A underlies influenza A virus polymerase host restriction. Nature (2016).
Jason S. Long, Efstathios S. Giotis, Olivier Moncorgé, Rebecca Frise, Bhakti Mistry, Joe James, Mireille Morisson, Munir Iqbal, Alain Vignal, Michael A. Skinner & Wendy S. Barclay
This paper identified a key factor that explained why the polymerases from avian influenza viruses are restricted in humans. For more, please see the associated New and Views.
See our latest ANP32 papers here: eLIFE, Journal of Virology, Journal of Virology.
The mechanism of resistance to favipiravir in influenza. PNAS (2018).
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Internal genes of a highly pathogenic H5N1 influenza virus determine high viral replication in myeloid cells and severe outcome of infection in mice. Plos Path. (2018).
Hui Li*, Konrad C. Bradley*, Jason S. Long, Rebecca Frise, Jonathan W. Ashcroft, Lorian C. Hartgroves, Holly Shelton, Spyridon Makris, Cecilia Johansson, Bin Cao & Wendy S. Barclay
Why do avian influenza viruses like H5N1 cause such severe disease in humans? This paper demonstrated that H5N1 viruses replicate better than human viruses in myeloid cells from mice leading to a cytokine storm and more severe disease.
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Journal articleCole SL, Dunning J, Kok WL, et al., 2017,
M1-like monocytes are a major immunological determinant of severity in previously healthy adults with life-threatening influenza., JCI Insight, Vol: 2, ISSN: 2379-3708
In each influenza season, a distinct group of young, otherwise healthy individuals with no risk factors succumbs to life-threatening infection. To better understand the cause for this, we analyzed a broad range of immune responses in blood from a unique cohort of patients, comprising previously healthy individuals hospitalized with and without respiratory failure during one influenza season, and infected with one specific influenza A strain. This analysis was compared with similarly hospitalized influenza patients with known risk factors (total of n = 60 patients recruited). We found a sustained increase in a specific subset of proinflammatory monocytes, with high TNF-α expression and an M1-like phenotype (independent of viral titers), in these previously healthy patients with severe disease. The relationship between M1-like monocytes and immunopathology was strengthened using murine models of influenza, in which severe infection generated using different models (including the high-pathogenicity H5N1 strain) was also accompanied by high levels of circulating M1-like monocytes. Additionally, a raised M1/M2 macrophage ratio in the lungs was observed. These studies identify a specific subtype of monocytes as a modifiable immunological determinant of disease severity in this subgroup of severely ill, previously healthy patients, offering potential novel therapeutic avenues.
Journal articlePeacock TP, Benton DJ, Sadeyen J-R, et al., 2017,
Variability in H9N2 haemagglutinin receptor-binding preference and the pH of fusion, EMERGING MICROBES & INFECTIONS, Vol: 6, ISSN: 2222-1751
H9N2 avian influenza viruses are primarily a disease of poultry; however, they occasionally infect humans and are considered a potential pandemic threat. Little work has been performed to assess the intrinsic biochemical properties related to zoonotic potential of H9N2 viruses. The objective of this study, therefore, was to investigate H9N2 haemagglutinins (HAs) using two well-known correlates for human adaption: receptor-binding avidity and pH of fusion. Receptor binding was characterized using bio-layer interferometry to measure virus binding to human and avian-like receptor analogues and the pH of fusion was assayed by syncytium formation in virus-infected cells at different pHs. We characterized contemporary H9N2 viruses of the zoonotic G1 lineage, as well as representative viruses of the zoonotic BJ94 lineage. We found that most contemporary H9N2 viruses show a preference for sulphated avian-like receptor analogues. However, the ‘Eastern’ G1 H9N2 viruses displayed a consistent preference in binding to a human-like receptor analogue. We demonstrate that the presence of leucine at position 226 of the HA receptor-binding site correlated poorly with the ability to bind a human-like sialic acid receptor. H9N2 HAs also display variability in their pH of fusion, ranging between pH 5.4 and 5.85 which is similar to that of the first wave of human H1N1pdm09 viruses but lower than the pH of fusion seen in zoonotic H5N1 and H7N9 viruses. Our results suggest possible molecular mechanisms that may underlie the relatively high prevalence of human zoonotic infection by particular H9N2 virus lineages.
Journal articleLipsitch M, Barclay W, Raman R, et al., 2016,
Viral factors in influenza pandemic risk assessment, eLife, Vol: 5, ISSN: 2050-084X
The threat of an influenza A virus pandemic stems from continual virus spillovers from reservoir species, a tiny fraction of which spark sustained transmission in humans. To date, no pandemic emergence of a new influenza strain has been preceded by detection of a closely related precursor in an animal or human. Nonetheless, influenza surveillance efforts are expanding, prompting a need for tools to assess the pandemic risk posed by a detected virus. The goal would be to use genetic sequence and/or biological assays of viral traits to identify those non-human influenza viruses with the greatest risk of evolving into pandemic threats, and/or to understand drivers of such evolution, to prioritize pandemic prevention or response measures. We describe such efforts, identify progress and ongoing challenges, and discuss three specific traits of influenza viruses (hemagglutinin receptor binding specificity, hemagglutinin pH of activation, and polymerase complex efficiency) that contribute to pandemic risk.
Journal articleDowall SD, Bewley K, Watson RJ, et al., 2016,
Antiviral Screening of Multiple Compounds against Ebola Virus, Viruses, Vol: 8, ISSN: 1999-4915
In light of the recent outbreak of Ebola virus (EBOV) disease in West Africa, there have been renewed efforts to search for effective antiviral countermeasures. A range of compounds currently available with broad antimicrobial activity have been tested for activity against EBOV. Using live EBOV, eighteen candidate compounds were screened for antiviral activity in vitro. The compounds were selected on a rational basis because their mechanisms of action suggested that they had the potential to disrupt EBOV entry, replication or exit from cells or because they had displayed some antiviral activity against EBOV in previous tests. Nine compounds caused no reduction in viral replication despite cells remaining healthy, so they were excluded from further analysis (zidovudine; didanosine; stavudine; abacavir sulphate; entecavir; JB1a; Aimspro; celgosivir; and castanospermine). A second screen of the remaining compounds and the feasibility of appropriateness for in vivo testing removed six further compounds (ouabain; omeprazole; esomeprazole; Gleevec; D-LANA-14; and Tasigna). The three most promising compounds (17-DMAG; BGB324; and NCK-8) were further screened for in vivo activity in the guinea pig model of EBOV disease. Two of the compounds, BGB324 and NCK-8, showed some effect against lethal infection in vivo at the concentrations tested, which warrants further investigation. Further, these data add to the body of knowledge on the antiviral activities of multiple compounds against EBOV and indicate that the scientific community should invest more effort into the development of novel and specific antiviral compounds to treat Ebola virus disease.
Journal articleJames J, Howard W, Iqbal M, et al., 2016,
Influenza A virus PB1-F2 protein prolongs viral shedding in chickens lengthening the transmission window, Journal of General Virology, Vol: 97, Pages: 2516-2527, ISSN: 1465-2099
Avian influenza is a significant economic burden on the poultry industry in geographical regions where it is enzootic. It also poses a public health concern when avian influenza subtypes infect humans, often with high mortality. Understanding viral genetic factors which positively contribute to influenza A virus (IAV) fitness – infectivity, spread and pathogenesis – is of great importance both for human and livestock health. PB1-F2 is a small accessory protein encoded by IAV and in mammalian hosts has been implicated in a wide range of functions that contribute to increased pathogenesis. In the avian host, the protein has been understudied despite high-level full-length conservation in avian IAV isolates, which is in contrast to the truncations of the PB1-F2 length frequently found in mammalian host isolates. Here we report that the presence of a full-length PB1-F2 protein, from a low pathogenicity H9N2 avian influenza virus, prolongs infectious virus shedding from directly inoculated chickens, thereby enhancing transmission of the virus by lengthening the transmission window to contact birds. As well as extending transmission, the presence of a full-length PB1-F2 suppresses pathogenicity evidenced by an increased minimum lethal dose in embryonated chicken eggs and increasing survival in directly infected birds when compared to a virus lacking an ORF for PB1-F2. We propose that there is a positive pressure to maintain a full-length functional PB1-F2 protein upon infection of avian hosts as it contributes to the effective transmission of IAV in the field.
Journal articlePizzuto MS, Silic-Benussi M, Ciminale V, et al., 2016,
An engineered avian-origin influenza A virus for pancreatic ductal adenocarcinoma virotherapy, JOURNAL OF GENERAL VIROLOGY, Vol: 97, Pages: 2166-2179, ISSN: 0022-1317
Journal articleFrise R, Bradley K, van Doremalen N, et al., 2016,
Contact transmission of influenza virus between ferrets imposes a looser bottleneck than respiratory droplet transmission allowing propagation of antiviral resistance, Scientific Reports, Vol: 6, ISSN: 2045-2322
Influenza viruses cause annual seasonal epidemics and occasional pandemics. It is important to elucidate the stringency of bottlenecks during transmission to shed light on mechanisms that underlie the evolution and propagation of antigenic drift, host range switching or drug resistance. The virus spreads between people by different routes, including through the air in droplets and aerosols, and by direct contact. By housing ferrets under different conditions, it is possible to mimic various routes of transmission. Here, we inoculated donor animals with a mixture of two viruses whose genomes differed by one or two reverse engineered synonymous mutations, and measured the transmission of the mixture to exposed sentinel animals. Transmission through the air imposed a tight bottleneck since most recipient animals became infected by only one virus. In contrast, a direct contact transmission chain propagated a mixture of viruses suggesting the dose transferred by this route was higher. From animals with a mixed infection of viruses that were resistant and sensitive to the antiviral drug oseltamivir, resistance was propagated through contact transmission but not by air. These data imply that transmission events with a looser bottleneck can propagate minority variants and may be an important route for influenza evolution.
Journal articleKobayashi Y, Dadonaite B, van Doremalen N, et al., 2016,
Computational and molecular analysis of conserved influenza A virus RNA secondary structures involved in infectious virion production, RNA Biology, ISSN: 1547-6286
As well as encoding viral proteins, genomes of RNA viruses harbor secondary and tertiary RNA structures that have been associated with functions essential for successful replication and propagation. Here, we identified stem-loop structures that are extremely conserved among 1,884 M segment sequences of influenza A virus (IAV) strains from various subtypes and host species using computational and evolutionary methods. These structures were predicted within the 3' and 5' ends of the coding regions of M1 and M2, respectively, where packaging signals have been previously proposed to exist. These signals are thought to be required for the incorporation of a single copy of eight different negative-strand RNA segments (vRNAs) into an IAV particle. To directly test the functionality of conserved stem-loop structures, we undertook reverse genetic experiments to introduce synonymous mutations designed to disrupt secondary structures predicted at three locations and found them to attenuate infectivity of recombinant virus. In one mutant, predicted to disrupt stem loop structure at nucleotide positions 219-240, attenuation was more evident at increased temperature and was accompanied by an increase in the production of defective virus particles. Our results suggest that the conserved secondary structures predicted in the M segment are involved in the production of infectious viral particles during IAV replication.
Journal articleElderfield RA, Koutsakos M, Frise R, et al., 2016,
NB protein does not affect Influenza B virus replication in vitro and is not required for replication in or transmission between ferrets., Journal of General Virology, Vol: 97, Pages: 593-601, ISSN: 1465-2099
The influenza B virus encodes a unique protein, NB, a membrane protein whose function in the replication cycle is not, as yet, understood. We engineered a recombinant influenza B virus lacking NB expression with no concomitant difference in expression or activity of viral neuraminidase protein, an important caveat since NA is encoded on the same segment and initiated from a start codon just 4 nucleotides downstream of NB. Replication of the virus lacking NB was not different to wild type virus with full length NB in clonal immortalized or complex primary cell cultures. In the mouse model, virus lacking NB induced slightly lower IFN levels in infected lungs but this did not affect virus titres or weight loss. In ferrets infected with a mixture of viruses that did or did not express NB, there was no fitness advantage for the virus that retained NB. Moreover, virus lacking NB protein was transmitted following respiratory droplet exposure of sentinel animals. These data suggest no role for NB in supporting replication or transmission in vivo in this animal model. The role of NB and the nature of selection to retain it in all natural influenza B viruses remain unclear.
Journal articlePeacock T, Reddy K, James J, et al., 2016,
Antigenic mapping of an H9N2 avian influenza virus reveals two discrete antigenic sites and a novel mechanism of immune escape, Scientific Reports, Vol: 6, ISSN: 2045-2322
H9N2 avian influenza virus is a major cause of poultry production loss across Asia leading to the wide useof vaccines. Efficacy of vaccines is often compromised due to the rapid emergence of antigenic variants.To improve the effectiveness of vaccines in the field, a better understanding of the antigenic epitopesof the major antigen, hemagglutinin, is required. To address this, a panel of nine monoclonal antibodieswere generated against a contemporary Pakistani H9N2 isolate, which represents a major Asian H9N2viral lineage. Antibodies were characterized in detail and used to select a total of 26 unique ‘escape’mutants with substitutions across nine different amino acid residues in hemagglutinin including seventhat have not been described as antigenic determinants for H9N2 viruses before. Competition assaysand structural mapping revealed two novel, discrete antigenic sites “H9-A” and “H9-B”. Additionally,a second subset of escape mutants contained amino acid deletions within the hemagglutinin receptorbinding site. This constitutes a novel method of escape for group 1 hemagglutinins and could representan alternative means for H9N2 viruses to overcome vaccine induced immunity. These results will guidesurveillance efforts for arising antigenic variants as well as evidence based vaccine seed selection andvaccine design.
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