Publications
56 results found
Giotis ES, Scott A, Rothwell L, et al., 2018, Chicken anaemia virus evades host immune responses in transformed lymphocytes., Journal of General Virology, Vol: 99, Pages: 321-327, ISSN: 1465-2099
Chicken anaemia virus (CAV) is a lymphotropic virus that causes anaemia and immunosuppression in chickens. Previously, we proposed that CAV evades host antiviral responses in vivo by disrupting T-cell signalling, but the precise cellular targets and modes of action remain elusive. In this study, we examined gene expression in Marek's disease virus-transformed chicken T-cell line MSB-1 after infection with CAV using both a custom 5K immune-focused microarray and quantitative real-time PCR at 24, 48 and 72 h post-infection. The data demonstrate an intricate equilibrium between CAV and the host gene expression, displaying subtle but significant modulation of transcripts involved in the T-cell, inflammation and NF-κB signalling cascades. CAV efficiently blocked the induction of type-I interferons and interferon-stimulated genes at 72 h. The cell expression pattern implies that CAV subverts host antiviral responses and that the transformed environment of MSB-1 cells offers an opportunistic advantage for virus growth.
Giotis ES, Ross CS, Robey RC, et al., 2017, Constitutively elevated levels of SOCS1 suppress innate responses in DF-1 immortalised chicken fibroblast cells, Scientific Reports, Vol: 7, ISSN: 2045-2322
The spontaneously immortalised DF-1 cell line is rapidly replacing its progenitor primary chicken embryo fibroblasts (CEFs) for studies on avian viruses such as avian influenza but no comprehensive study has as yet been reported comparing their innate immunity phenotypes. We conducted microarray analyses of DF-1 and CEFs, under both normal and stimulated conditions using chicken interferon-α (chIFNα) and the attenuated infectious bursal disease virus vaccine strain PBG98. We found that DF-1 have an attenuated innate response compared to CEFs. Basal expression levels of Suppressor of Cytokine Signalling 1 (chSOCS1), a negative regulator of cytokine signalling in mammals, are 16-fold higher in DF-1 than in CEFs. The chSOCS1 “SOCS box” domain (which, in mammals, interacts with an E3 ubiquitin ligase complex) is not essential for the inhibition of cytokine-induced JAK/STAT signalling activation in DF-1. Overexpression of SOCS1 in chIFNα-stimulated DF-1 led to a relative decrease in expression of interferon-stimulated genes (ISGs; MX1 and IFIT5) and increased viral yield in response to PBG98 infection. Conversely, knockdown of SOCS1 enhanced induction of ISGs and reduced viral yield in chIFNα-stimulated DF-1. Consequently, SOCS1 reduces induction of the IFN signalling pathway in chicken cells and can potentiate virus replication.
Dulwich KL, Giotis ES, Gray A, et al., 2017, Differential gene expression in chicken primary B cells infected ex vivo with attenuated and very virulent strains of infectious bursal disease virus (IBDV)., Journal of General Virology, Vol: 98, Pages: 2918-2930, ISSN: 1465-2099
Infectious bursal disease virus (IBDV) belongs to the family Birnaviridae and is economically important to the poultry industry worldwide. IBDV infects B cells in the bursa of Fabricius (BF), causing immunosuppression and morbidity in young chickens. In addition to strains that cause classical Gumboro disease, the so-called 'very virulent' (vv) strain, also in circulation, causes more severe disease and increased mortality. IBDV has traditionally been controlled through the use of live attenuated vaccines, with attenuation resulting from serial passage in non-lymphoid cells. However, the factors that contribute to the vv or attenuated phenotypes are poorly understood. In order to address this, we aimed to investigate host cell-IBDV interactions using a recently described chicken primary B-cell model, where chicken B cells are harvested from the BF and cultured ex vivo in the presence of chicken CD40L. We demonstrated that these cells could support the replication of IBDV when infected ex vivo in the laboratory. Furthermore, we evaluated the gene expression profiles of B cells infected with an attenuated strain (D78) and a very virulent strain (UK661) by microarray. We found that key genes involved in B-cell activation and signalling (TNFSF13B, CD72 and GRAP) were down-regulated following infection relative to mock, which we speculate could contribute to IBDV-mediated immunosuppression. Moreover, cells responded to infection by expressing antiviral type I IFNs and IFN-stimulated genes, but the induction was far less pronounced upon infection with UK661, which we speculate could contribute to its virulence.
Dulwich K, Giotis E, Gray A, et al., 2017, Differential gene expression in chicken primary B cells infected ex vivo with attenuated and very virulent strains of infectious bursal disease virus (IBDV), Journal of General Virology, ISSN: 1465-2099
Abstract Infectious bursal disease virus (IBDV) belongs to the family Birnaviridae and is economically important to the poultry industry worldwide. IBDV infects B cells in the bursa of Fabricius (BF), causing immunosuppression and morbidity in young chickens. In addition to strains that cause classical Gumboro disease, the so-called ‘very virulent’ (vv) strain, also in circulation, causes more severe disease and increased mortality. IBDV has traditionally been controlled through the use of live attenuated vaccines, with attenuation resulting from serial passage in non-lymphoid cells. However, the factors that contribute to the vv or attenuated phenotypes are poorly understood. In order to address this, we aimed to investigate host cell-IBDV interactions using a recently described chicken primary B cell model, where chicken B cells are harvested from the BF and cultured ex vivo in the presence of chicken CD40L. We demonstrated that these cells could support the replication of IBDV when infected ex vivo in the laboratory. Furthermore, we evaluated the gene expression profiles of B cells infected with an attenuated strain (D78) and a very virulent strain (UK661) by microarray. We found that key genes involved in B cell activation and signaling (TNFSF13B, CD72 and GRAP) were down-regulated following infection relative to mock, which we speculate could contribute to IBDV-mediated immunosuppression. Moreover, cells responded to infection by expressing antiviral type I IFNs and IFN-stimulated genes, but the induction was far less pronounced upon infection with UK661, which we speculate could contribute to its virulence.
Tierney M, Gallagher AM, Giotis ES, et al., 2017, An online survey on consumer knowledge and understanding of added sugars, Nutrients, Vol: 9, ISSN: 2072-6643
Evidence of an association between added sugars (AS) and the risk of obesity has triggered public health bodies to develop strategies enabling consumers to manage their AS intake. The World Health Organisation (WHO) has strongly recommended a reduction of free sugars to 10% of total dietary energy (TE) and conditionally recommended a reduction to 5% TE to achieve health benefits. Despite food labelling being a policy tool of choice in many countries, there is no consensus on the mandatory addition of AS to the nutrition panel of food labels. An online survey was conducted to explore consumer ability to identify AS on food labels and to investigate consumer awareness of the WHO guidelines in relation to sugar intakes. The questionnaire was tested for participant comprehension using face-to-face interviews prior to conducting the online study. The online survey was conducted in Northern Ireland during May 2015 and was completed by a convenient sample of 445 subjects. Results showed that just 4% of respondents correctly classified 10 or more ingredients from a presented list of 13 items, while 65% of participants were unaware of the WHO guidelines for sugar intake. It may be timely to reopen dialogue on inclusion of AS on food product nutrition panels.
Giotis ES, Robey RC, Skinner NG, et al., 2016, Chicken interferome: avian interferon-stimulated genes identified by microarray and RNA-seq of primary chick embryo fibroblasts treated with a chicken type I interferon (IFN-α), Veterinary Research, Vol: 47, ISSN: 1297-9716
Viruses that infect birds pose major threats—to the global supply of chicken, the major, universally-acceptable meat, and as zoonotic agents (e.g. avian influenza viruses H5N1 and H7N9). Controlling these viruses in birds as well as understanding their emergence into, and transmission amongst, humans will require considerable ingenuity and understanding of how different species defend themselves. The type I interferon-coordinated response constitutes the major antiviral innate defence. Although interferon was discovered in chicken cells, details of the response, particularly the identity of hundreds of stimulated genes, are far better described in mammals. Viruses induce interferon-stimulated genes but they also regulate the expression of many hundreds of cellular metabolic and structural genes to facilitate their replication. This study focusses on the potentially anti-viral genes by identifying those induced just by interferon in primary chick embryo fibroblasts. Three transcriptomic technologies were exploited: RNA-seq, a classical 3′-biased chicken microarray and a high density, “sense target”, whole transcriptome chicken microarray, with each recognising 120–150 regulated genes (curated for duplication and incorrect assignment of some microarray probesets). Overall, the results are considered robust because 128 of the compiled, curated list of 193 regulated genes were detected by two, or more, of the technologies.
Long JS, Giotis ES, Moncorgé O, et al., 2016, Species difference in ANP32A underlies influenza A virus polymerase host restriction, Nature, Vol: 529, Pages: 101-104, ISSN: 0028-0836
Influenza pandemics occur unpredictably when zoonotic influenza viruses with novel antigenicity acquire the ability to transmit amongst humans. Host range breaches are limited by incompatibilities between avian virus components and the human host. Barriers include receptor preference, virion stability and poor activity of the avian virus RNA-dependent RNA polymerase in human cells. Mutants of the heterotrimeric viral polymerase components, particularly PB2 protein, are selected during mammalian adaptation, but their mode of action is unknown. We show that a species-specific difference in host protein ANP32A accounts for the suboptimal function of avian virus polymerase in mammalian cells. Avian ANP32A possesses an additional 33 amino acids between the leucine-rich repeats and carboxy-terminal low-complexity acidic region domains. In mammalian cells, avian ANP32A rescued the suboptimal function of avian virus polymerase to levels similar to mammalian-adapted polymerase. Deletion of the avian-specific sequence from chicken ANP32A abrogated this activity, whereas its insertion into human ANP32A, or closely related ANP32B, supported avian virus polymerase function. Substitutions, such as PB2(E627K), were rapidly selected upon infection of humans with avian H5N1 or H7N9 influenza viruses, adapting the viral polymerase for the shorter mammalian ANP32A. Thus ANP32A represents an essential host partner co-opted to support influenza virus replication and is a candidate host target for novel antivirals.
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- Citations: 186
Giotis ES, Robey RR, Ross C, et al., 2015, Transcriptomic analysis of the chicken interferome, 3rd Annual Meeting of the International-Cytokine-and-Interferon-Society (ICIS), Publisher: Elsevier, Pages: 104-104, ISSN: 1043-4666
Giotis ES, Robey RR, Ross C, et al., 2015, Immunodulation and proviral action of chicken Suppressor of Cytokine Signaling 1 (SOCS1), 3rd Annual Meeting of the International-Cytokine-and-Interferon-Society (ICIS), Publisher: Elsevier, Pages: 90-90, ISSN: 1043-4666
Giotis ES, Rothwell L, Scott A, et al., 2015, Transcriptomic Profiling of Virus-Host Cell Interactions following Chicken Anaemia Virus (CAV) Infection in an In Vivo Model., PLOS One, Vol: 10, Pages: e0134866-e0134866, ISSN: 1932-6203
Chicken Anaemia Virus (CAV) is an economically important virus that targets lymphoid and erythroblastoid progenitor cells leading to immunosuppression. This study aimed to investigate the interplay between viral infection and the host's immune response to better understand the pathways that lead to CAV-induced immunosuppression. To mimic vertical transmission of CAV in the absence of maternally-derived antibody, day-old chicks were infected and their responses measured at various time-points post-infection by qRT-PCR and gene expression microarrays. The kinetics of mRNA expression levels of signature cytokines of innate and adaptive immune responses were determined by qRT-PCR. The global gene expression profiles of mock-infected (control) and CAV-infected chickens at 14 dpi were also compared using a chicken immune-related 5K microarray. Although in the thymus there was evidence of induction of an innate immune response following CAV infection, this was limited in magnitude. There was little evidence of a Th1 adaptive immune response in any lymphoid tissue, as would normally be expected in response to viral infection. Most cytokines associated with Th1, Th2 or Treg subsets were down-regulated, except IL-2, IL-13, IL-10 and IFNγ, which were all up-regulated in thymus and bone marrow. From the microarray studies, genes that exhibited significant (greater than 1.5-fold, false discovery rate <0.05) changes in expression in thymus and bone marrow on CAV infection were mainly associated with T-cell receptor signalling, immune response, transcriptional regulation, intracellular signalling and regulation of apoptosis. Expression levels of a number of adaptor proteins, such as src-like adaptor protein (SLA), a negative regulator of T-cell receptor signalling and the transcription factor Special AT-rich Binding Protein 1 (SATB1), were significantly down-regulated by CAV infection, suggesting potential roles for these genes as regulators of viral infection or cell def
Ascough S, Sadeyen J-R, Giotis E, et al., 2014, Potentiating the immunogenicity of poxvirus vectors to improve the efficacy of live recombinant viral vaccines in poultry, IMMUNOLOGY, Vol: 143, Pages: 66-66, ISSN: 0019-2805
Kennedy TG, Giotis ES, McKevitt AI, 2014, Microbial assessment of an upward and downward dehiding technique in a commercial beef processing plant, MEAT SCIENCE, Vol: 97, Pages: 486-489, ISSN: 0309-1740
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- Citations: 9
Wheatley P, Giotis ES, McKevitt AI, 2014, Effects of slaughtering operations on carcass contamination in an Irish pork production plant, IRISH VETERINARY JOURNAL, Vol: 67, ISSN: 0368-0762
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- Citations: 30
Laidlaw SM, Robey R, Davies M, et al., 2013, Genetic Screen of a Mutant Poxvirus Library Identifies an Ankyrin Repeat Protein Involved in Blocking Induction of Avian Type I Interferon, Journal of Virology, Vol: 87, ISSN: 1098-5514
Mammalian poxviruses, including vaccinia virus (VACV), have evolved multiple mechanisms to evade the host type I interferon (IFN) responses at different levels, with viral proteins targeting IFN induction, signaling and antiviral effector functions. Avian poxviruses (avipoxviruses), which have been developed as recombinant vaccine vectors for permissive (i.e. poultry) and non-permissive (i.e. mammals, including humans) species, encode no obvious equivalents of any of these proteins. We show that fowlpox virus (FWPV) fails to induce chicken IFN-beta (ChIFN2) and is able to block its induction by transfected poly(I:C), an analog of cytoplasmic double-strand (ds) RNA. A broad-scale loss-of-function genetic screen was used to find FWPV-encoded modulators of poly(I:C)-mediated ChIFN2 induction. It identified fpv012, a member of a family of poxvirus genes, highly expanded in the avipoxviruses (31 in FWPV; 51 in canarypox virus (CNPV), representing 15% of the total gene complement), encoding proteins containing N-terminal ankyrin repeats (ANKs) and C-terminal F-box-like motifs. Under ectopic expression, the first ANK of fpv012 is dispensable for inhibitory activity and the CNPV ortholog is also able to inhibit induction of ChIFN2. FWPV defective in fpv012 replicate well in culture and barely induce ChIFN2 during infection, suggesting other factors are involved in blocking IFN induction and resisting the antiviral effectors. Nevertheless, unlike parental and revertant viruses, the mutants induce moderate levels of expression of interferon stimulated genes (ISG), suggesting either that there is sufficient ChIFN2 expression to partially induce the ISGs or the involvement of alternative, IFN-independent pathways, that are also normally blocked by fpv012.
Porphyre T, Giotis ES, Lloyd DH, et al., 2012, A Metapopulation Model to Assess the Capacity of Spread of Meticillin-Resistant <i>Staphylococcus aureus</i> ST398 in Humans, PLOS ONE, Vol: 7, ISSN: 1932-6203
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- Citations: 15
Giotis ES, Loeffler A, Knight-Jones T, et al., 2012, Development of a skin colonization model in gnotobiotic piglets for the study of the microbial ecology of meticillin-resistant Staphylococcus aureus ST398, JOURNAL OF APPLIED MICROBIOLOGY, Vol: 113, Pages: 992-1000, ISSN: 1364-5072
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- Citations: 7
Carson M, Meredith AL, Shaw DJ, et al., 2012, Foxes As a Potential Wildlife Reservoir for <i>mecA</i>-Positive Staphylococci, VECTOR-BORNE AND ZOONOTIC DISEASES, Vol: 12, Pages: 583-587, ISSN: 1530-3667
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- Citations: 10
Giotis ES, Loeffler A, Lindsay JA, et al., 2011, Reduced Sensitivity of Oxacillin-Screening Agar for Detection of MRSA ST398 from Colonized Pigs, JOURNAL OF CLINICAL MICROBIOLOGY, Vol: 49, Pages: 3103-3104, ISSN: 0095-1137
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- Citations: 1
Giotis ES, Blair IS, McDowell DA, 2011, Standardisation and optimisation of the Alkaline-Tolerance Response (A1TR) in <i>Listeria monocytogenes</i> 10403S, 3rd International Conference on Environmental, Industrial, and Applied Microbiology (BioMicroWorld 2009), Publisher: WORLD SCIENTIFIC PUBL CO PTE LTD, Pages: 441-445
Giotis ES, Muthaiyan A, Natesan S, et al., 2010, Transcriptome Analysis of Alkali Shock and Alkali Adaptation in <i>Listeria monocytogenes</i> 10403S, FOODBORNE PATHOGENS AND DISEASE, Vol: 7, Pages: 1147-1157, ISSN: 1535-3141
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- Citations: 20
Krysa J, Zita J, Zlamal M, et al., 2010, Ability of Photocatalytic TiO<sub>2</sub> Surfaces to Destroy MRSA ST398 under Controlled UV Light Conditions, 6th European Meeting on Solar Chemistry and Photocatalysis: Environmental Applications (SPEA6), Publisher: ICT PRESS, Pages: 333-333
Singh VK, Hattangady DS, Giotis ES, et al., 2008, Insertional inactivation of branched-chain α-keto acid dehydrogenase in <i>Staphylococcus aureus</i> leads to decreased branched-chain membrane fatty acid content and increased susceptibility to certain stresses, APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Vol: 74, Pages: 5882-5890, ISSN: 0099-2240
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- Citations: 79
Giotis ES, Julotok M, Wilkinson BJ, et al., 2008, Role of sigma B factor in the alkaline tolerance response of <i>Listeria monocytogenes</i> 10403S and cross-protection against subsequent ethanol and osmotic stress, JOURNAL OF FOOD PROTECTION, Vol: 71, Pages: 1481-1485, ISSN: 0362-028X
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- Citations: 22
Giotis ES, Muthaiyan A, Blair IS, et al., 2008, Genomic and proteomic analysis of the Alkali-Tolerance Response (AlTR) in <i>Listeria monocytogenes</i> 10403S, BMC MICROBIOLOGY, Vol: 8, ISSN: 1471-2180
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- Citations: 43
Giotis ES, Blair IS, McDowell DA, 2007, Morphological changes in <i>Listeria monocytogenes</i> subjected to sublethal alkaline stress, INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY, Vol: 120, Pages: 250-258, ISSN: 0168-1605
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- Citations: 49
Giotis ES, McDowell DA, Blair IS, et al., 2007, Role of branched-chain fatty acids in pH stress tolerance in <i>Listeria monocytogenes</i>, APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Vol: 73, Pages: 997-1001, ISSN: 0099-2240
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- Citations: 102
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