The Experts below are selected from a list of 114 Experts worldwide ranked by ideXlab platform
Tanya A. Miura - One of the best experts on this subject based on the ideXlab platform.
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Neutrophils are needed for an effective immune response against pulmonary Rat Coronavirus infection, but also contribute to pathology
Journal of General Virology, 2014Co-Authors: Anoria K. Haick, Joanna P. Rzepka, Elizabeth Brandon, Onesmo B. Balemba, Tanya A. MiuraAbstract:Polymorphonuclear neutrophils (PMN) infiltRate the respiRatory tract early after viral infection and can contribute to both host defence and pathology. Coronaviruses are important causes of respiRatory tract infections, ranging from mild to severe depending on the viral strain. This study evaluated the role of PMN during a non-fatal pulmonary Coronavirus infection in the natural host. Rat Coronavirus (RCoV) causes respiRatory disease in adult Rats, characterized by an early PMN response, viral replication and inflammatory lesions in the lungs, mild weight loss and effective resolution of infection. To determine their role during RCoV infection, PMN were depleted and the effects on disease progression, viral replication, inflammatory response and lung pathology were analysed. Compared with RCoV infection in control animals, PMN-depleted Rats had worsened disease with weight loss, clinical signs, mortality and prolonged pulmonary viral replication. PMN-depleted animals had fewer macrophages and lymphocytes in the respiRatory tract, corresponding to lower chemokine levels. Combined with in vitro experiments showing that PMN express cytokines and chemokines in response to RCoV-infected alveolar epithelial cells, these findings support a role for PMN in eliciting an inflammatory response to RCoV infection. Despite their critical role in the protection from severe disease, the presence of PMN was correlated with haemorrhagic lesions, epithelial barrier permeability and cellular inflammation in the lungs. This study demonstRated that while PMN are required for an effective antiviral response, they also contribute to lung pathology during RCoV infection.
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Virus-infected alveolar epithelial cells direct neutrophil chemotaxis and inhibit their apoptosis.
American journal of respiratory cell and molecular biology, 2012Co-Authors: Joanna P. Rzepka, Anoria K. Haick, Tanya A. MiuraAbstract:The alveolar epithelium is a critical target for pulmonary viruses and can produce proinflammatory cytokines and chemokines upon viral infection. However, the molecular interactions between virus-infected alveolar epithelial cells and inflammatory cells, including polymorphonuclear leukocytes (PMNs), have not been thoroughly characterized. Rat Coronavirus (RCoV) is used as a model to study the immune response to viral infection in the lung of the natural host. We have developed an in vitro model to characterize the response of PMNs to RCoV-infected type I-like alveolar epithelial (AT1) cells, the primary target for RCoV infection in the alveoli. Multiple CXC chemokines that signal through CXCR2 were required for PMN chemotaxis toward medium from RCoV-infected AT1-like cells (RCoV-AT1). Furthermore, RCoV-AT1 inhibited spontaneous PMN apoptosis, including activation of effector caspase 3 and initiator caspases 8 and 9. Use of a selective inhibitor of CXCR2, SB265610, demonstRated that CXCR2 signaling was required for RCoV-AT1-mediated inhibition of PMN apoptosis. These data suggest that CXC chemokines produced by RCoV-infected AT1-like cells inhibit PMN apoptosis during infection. These studies provide new insight into the molecular mechanisms whereby alveolar epithelial cells direct the functions of PMNs during viral infection of the lung.
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Rat respiRatory Coronavirus infection: replication in airway and alveolar epithelial cells and the innate immune response
Journal of General Virology, 2009Co-Authors: C. Joel Funk, Kathryn V Holmes, Tanya A. Miura, Rizwan Manzer, Steve D. Groshong, Yoko Ito, Emily A. Travanty, Jennifer Leete, Robert J. MasonAbstract:The Rat Coronavirus sialodacryoadenitis virus (SDAV) causes respiRatory infection and provides a system for investigating respiRatory Coronaviruses in a natural host. A viral suspension in the form of a microspray aerosol was delivered by intRatracheal instillation into the distal lung of 6–8-week-old Fischer 344 Rats. SDAV inoculation produced a 7 % body weight loss over a 5 day period that was followed by recovery over the next 7 days. SDAV caused focal lesions in the lung, which were most severe on day 4 post-inoculation (p.i.). Immunofluorescent staining showed that four cell types supported SDAV virus replication in the lower respiRatory tract, namely Clara cells, ciliated cells in the bronchial airway and alveolar type I and type II cells in the lung parenchyma. In bronchial alveolar lavage fluid (BALF) a neutrophil influx increased the population of neutrophils to 45 % compared with 6 % of the cells in control samples on day 2 after mock inoculation. Virus infection induced an increase in surfactant protein SP-D levels in BALF of infected Rats on days 4 and 8 p.i. that subsided by day 12. The concentRations of chemokines MCP-1, LIX and CINC-1 in BALF increased on day 4 p.i., but returned to control levels by day 8. IntRatracheal instillation of Rats with SDAV Coronavirus caused an acute, self-limited infection that is a useful model for studying the early events of the innate immune response to respiRatory Coronavirus infections in lungs of the natural virus host.
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Host-pathogen interactions during Coronavirus infection of primary alveolar epithelial cells.
Journal of Leukocyte Biology, 2009Co-Authors: Tanya A. Miura, Kathryn V HolmesAbstract:Viruses that infect the lung are a significant cause of morbidity and mortality in animals and humans worldwide. Coronaviruses are being associated increasingly with severe diseases in the lower respiRatory tract. Alveolar epithelial cells are an important target for Coronavirus infection in the lung, and infected cells can initiate innate immune responses to viral infection. In this overview, we describe in vitro models of highly differentiated alveolar epithelial cells that are currently being used to study the innate immune response to Coronavirus infection. We have shown that Rat Coronavirus infection of Rat alveolar type I epithelial cells in vitro induces expression of CXC chemokines, which may recruit and activate neutrophils. Although neutrophils are recruited early in infection in several Coronavirus models including Rat Coronavirus. However, their role in viral clearance and/or immune-mediated tissue damage is not understood. Primary cultures of differentiated alveolar epithelial cells will be useful for identifying the interactions between Coronaviruses and alveolar epithelial cells that influence the innate immune responses to infection in the lung. Understanding the molecular details of these interactions will be critical for the design of effective stRategies to prevent and treat Coronavirus infections in the lung.
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Rat Coronaviruses infect Rat alveolar type I epithelial cells and induce expression of CXC chemokines.
Virology, 2007Co-Authors: Tanya A. Miura, Kathryn V Holmes, Jieru Wang, Robert J. MasonAbstract:We analyzed the ability of two Rat Coronavirus (RCoV) strains, sialodacryoadenitis virus (SDAV) and Parker's RCoV (RCoV-P), to infect Rat alveolar type I cells and induce chemokine expression. Primary Rat alveolar type II cells were transdifferentiated into the type I cell phenotype. Type I cells were productively infected with SDAV and RCoV-P, and both live virus and UV-inactivated virus induced mRNA and protein expression of three CXC chemokines: CINC-2, CINC-3, and LIX, which are neutrophil chemoattractants. Dual immunolabeling of type I cells for viral antigen and CXC chemokines showed that chemokines were expressed primarily by uninfected cells. Virus-induced chemokine expression was reduced by the IL-1 receptor antagonist, suggesting that IL-1 produced by infected cells induces uninfected cells to express chemokines. Primary cultures of alveolar epithelial cells are an important model for the early events in viral infection that lead to pulmonary inflammation.
Reinhard Vlasak - One of the best experts on this subject based on the ideXlab platform.
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Infectious Salmon Anemia Virus Specifically Binds to and Hydrolyzes 4-O-Acetylated Sialic Acids
Journal of virology, 2004Co-Authors: Audny Hellebø, Ulrike Vilas, Knut Falk, Reinhard VlasakAbstract:Infectious salmon anemia virus (ISAV) is the causative agent of infections in farmed Atlantic salmon. ISAV presumably represents a new genus within the Orthomyxoviridae. ISAV has been shown earlier to exhibit a receptor-destroying activity, which was defined as an acetylesterase with unknown specificity. We have analyzed the substRate specificity of the ISAV esterase in detail. Purified ISAV hydrolyzed free 5-N-acetyl-4-O-acetyl neuraminic acid. In addition, the purified 9-O-acetylated sialic acid derivative was also hydrolyzed, but at lower Rates. When we used a glycosidically bound substRate, ISAV was unable to hydrolyze 9-O-acetylated sialic acid, which represents the major substRate for the influenza C virus esterase. ISAV completely de-O-acetylated glycoprotein-bound 5-N-acetyl-4-O-acetyl neuraminic acid. Thus, the enzymatic activity of the hemagglutinin-esterase of ISAV is comparable to that of the sialate-4-O-esterases of murine Coronaviruses and related group 2 Coronaviruses. In addition, we found that ISAV specifically binds to glycoproteins containing 4-O-acetylated sialic acids. Both the ISAV esterase and recombinant Rat Coronavirus esterase specific for 4-O-acetylated sialic acids hydrolyzed ISAV receptors on horse and rabbit erythrocytes, indicating that this sialic acid represents a receptor determinant for ISAV.
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Recombinant viral sialate-O-acetylesterases.
Glycoconjugate journal, 2004Co-Authors: Peter Strasser, Ulrike Unger, Birgit Strobl, Ulrike Vilas, Reinhard VlasakAbstract:Viral O-acetylesterases were first identified in several viruses, including influenza C viruses and Coronaviruses. These enzymes are capable of removing cellular receptors from the surface of target cells. Hence they are also known as "receptor destroying" enzymes. We have cloned and expressed several recombinant viral O-acetylesterases. These enzymes were secreted from Sf9 insect cells as chimeric proteins fused to eGFP. A purification scheme to isolate the recombinant O-acetylesterase of influenza C virus was developed. The recombinant enzymes derived from influenza C viruses specifically hydrolyze 9-O-acetylated sialic acids, while that of sialodacryoadenitis virus, a Rat Coronavirus related to mouse hepatitis virus, is specific for 4-O-acetylated sialic acid. The recombinant esterases were shown to specifically de-O-acetylate sialic acids on glycoconjugates. We have also expressed esterase knockout proteins of the influenza C virus hemagglutinin-esterase. The recombinant viral proteins can be used to unambiguously identify O-acetylated acids in a variety of assays.
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Recombinant viral sialate-O-acetylesterases
Glycoconjugate Journal, 2003Co-Authors: Peter Strasser, Ulrike Unger, Birgit Strobl, Ulrike Vilas, Reinhard VlasakAbstract:Viral O -acetylesterases were first identified in several viruses, including influenza C viruses and Coronaviruses. These enzymes are capable of removing cellular receptors from the surface of target cells. Hence they are also known as “receptor destroying” enzymes. We have cloned and expressed several recombinant viral O-acetylesterases. These enzymes were secreted from Sf9 insect cells as chimeric proteins fused to eGFP. A purification scheme to isolate the recombinant O -acetylesterase of influenza C virus was developed. The recombinant enzymes derived from influenza C viruses specifically hydrolyze 9- O -acetylated sialic acids, while that of sialodacryoadenitis virus, a Rat Coronavirus related to mouse hepatitis virus, is specific for 4- O -acetylated sialic acid. The recombinant esterases were shown to specifically de- O -acetylate sialic acids on glycoconjugates. We have also expressed esterase knockout proteins of the influenza C virus hemagglutinin-esterase. The recombinant viral proteins can be used to unambiguously identify O -acetylated acids in a variety of assays. Published in 2004. .
J. D. Macy - One of the best experts on this subject based on the ideXlab platform.
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reverse transcriptase polymerase chain reaction based diagnosis and molecular characterization of a new Rat Coronavirus strain
Laboratory Animal Science, 1999Co-Authors: S. R. Compton, B E Vivasgonzalez, J. D. MacyAbstract:BACKGROUND AND PURPOSE Rat Coronaviruses (RCV) are highly infectious and spread rapidly through laboRatory Rat colonies, causing sneezing, nasal and ocular discharges, photophobia, and cervical swelling. Current diagnostic methods include serologic testing and histologic examination. During a recent Rat Coronavirus outbreak, we tested a rapid, noninvasive method of RCV diagnosis that involved use of reverse transcriptase-polymerase chain reaction (RT-PCR) analysis to detect RCV RNA on cages housing infected Rats. METHODS The RT-PCR was used to detect RCV RNA in tissues from infected Rats and on cages housing infected Rats and to amplify portions of the RCV N, M, and S genes for molecular characterization. RESULTS The RT-PCR detected RCV RNA on cages and in tissues from infected Rats. The RCV-NJ N gene is most closely related to the MHV-Y N gene. The M proteins of RCV-NJ and RCV-SDA are 99% homologous, and the six RCV S protein fragments are 97 to 100% homologous. CONCLUSIONS Use of RT-PCR with cage-swab specimens was capable of diagnosing RCV infection in and viral excretion from Rats. Additionally, molecular characterization of the N, M, and S genes of RCV-NJ provided baseline information that can be used in performing further epidemiologic studies.
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Reverse transcriptase polymerase chain reaction-based diagnosis and molecular characterization of a new Rat Coronavirus strain.
Laboratory animal science, 1999Co-Authors: S. R. Compton, B. E. Vivas-gonzalez, J. D. MacyAbstract:Rat Coronaviruses (RCV) are highly infectious and spread rapidly through laboRatory Rat colonies, causing sneezing, nasal and ocular discharges, photophobia, and cervical swelling. Current diagnostic methods include serologic testing and histologic examination. During a recent Rat Coronavirus outbreak, we tested a rapid, noninvasive method of RCV diagnosis that involved use of reverse transcriptase-polymerase chain reaction (RT-PCR) analysis to detect RCV RNA on cages housing infected Rats. The RT-PCR was used to detect RCV RNA in tissues from infected Rats and on cages housing infected Rats and to amplify portions of the RCV N, M, and S genes for molecular characterization. The RT-PCR detected RCV RNA on cages and in tissues from infected Rats. The RCV-NJ N gene is most closely related to the MHV-Y N gene. The M proteins of RCV-NJ and RCV-SDA are 99% homologous, and the six RCV S protein fragments are 97 to 100% homologous. Use of RT-PCR with cage-swab specimens was capable of diagnosing RCV infection in and viral excretion from Rats. Additionally, molecular characterization of the N, M, and S genes of RCV-NJ provided baseline information that can be used in performing further epidemiologic studies.
Robert J. Mason - One of the best experts on this subject based on the ideXlab platform.
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Rat respiRatory Coronavirus infection: replication in airway and alveolar epithelial cells and the innate immune response
Journal of General Virology, 2009Co-Authors: C. Joel Funk, Kathryn V Holmes, Tanya A. Miura, Rizwan Manzer, Steve D. Groshong, Yoko Ito, Emily A. Travanty, Jennifer Leete, Robert J. MasonAbstract:The Rat Coronavirus sialodacryoadenitis virus (SDAV) causes respiRatory infection and provides a system for investigating respiRatory Coronaviruses in a natural host. A viral suspension in the form of a microspray aerosol was delivered by intRatracheal instillation into the distal lung of 6–8-week-old Fischer 344 Rats. SDAV inoculation produced a 7 % body weight loss over a 5 day period that was followed by recovery over the next 7 days. SDAV caused focal lesions in the lung, which were most severe on day 4 post-inoculation (p.i.). Immunofluorescent staining showed that four cell types supported SDAV virus replication in the lower respiRatory tract, namely Clara cells, ciliated cells in the bronchial airway and alveolar type I and type II cells in the lung parenchyma. In bronchial alveolar lavage fluid (BALF) a neutrophil influx increased the population of neutrophils to 45 % compared with 6 % of the cells in control samples on day 2 after mock inoculation. Virus infection induced an increase in surfactant protein SP-D levels in BALF of infected Rats on days 4 and 8 p.i. that subsided by day 12. The concentRations of chemokines MCP-1, LIX and CINC-1 in BALF increased on day 4 p.i., but returned to control levels by day 8. IntRatracheal instillation of Rats with SDAV Coronavirus caused an acute, self-limited infection that is a useful model for studying the early events of the innate immune response to respiRatory Coronavirus infections in lungs of the natural virus host.
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Rat Coronaviruses infect Rat alveolar type I epithelial cells and induce expression of CXC chemokines.
Virology, 2007Co-Authors: Tanya A. Miura, Kathryn V Holmes, Jieru Wang, Robert J. MasonAbstract:We analyzed the ability of two Rat Coronavirus (RCoV) strains, sialodacryoadenitis virus (SDAV) and Parker's RCoV (RCoV-P), to infect Rat alveolar type I cells and induce chemokine expression. Primary Rat alveolar type II cells were transdifferentiated into the type I cell phenotype. Type I cells were productively infected with SDAV and RCoV-P, and both live virus and UV-inactivated virus induced mRNA and protein expression of three CXC chemokines: CINC-2, CINC-3, and LIX, which are neutrophil chemoattractants. Dual immunolabeling of type I cells for viral antigen and CXC chemokines showed that chemokines were expressed primarily by uninfected cells. Virus-induced chemokine expression was reduced by the IL-1 receptor antagonist, suggesting that IL-1 produced by infected cells induces uninfected cells to express chemokines. Primary cultures of alveolar epithelial cells are an important model for the early events in viral infection that lead to pulmonary inflammation.
D. H. Percy - One of the best experts on this subject based on the ideXlab platform.
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Effect of time of exposure to Rat Coronavirus and Mycoplasma pulmonis on respiRatory tract lesions in the Wistar Rat.
Canadian journal of veterinary research = Revue canadienne de recherche veterinaire, 1995Co-Authors: M K Schunk, D. H. Percy, S RosendalAbstract:The effects of time of exposure on the progression of pulmonary lesions in Rats inoculated with Mycoplasma pulmonis and the Rat Coronavirus, sialodacryoadenitis virus (SDAV) were studied, using six groups of 18 SPF Wistar Rats (n = 108). Rats were inoculated intranasally as follows: Group 1, sterile medium only; Group 2, sterile medium followed one week later by 150 TCID50 SDAV; Group 3, sterile medium followed by 10(5.7) colony forming units of M. pulmonis; Group 4, SDAV followed one week later by M. pulmonis; Group 5, M. pulmonis followed one week later by SDAV; Group 6, M. pulmonis followed two weeks later by SDAV. Six Rats from each group were euthanized at one, two and three weeks after the final inoculation. In a sepaRate experiment, six additional animals were inoculated in each of groups 3, 5 and 6 (n = 18) and were sampled at five weeks after they had received M. pulmonis. Bronchoalveolar lavage and quantitative lung mycoplasma cultures were conducted on two-thirds of the Rats. Histopathological examination and scoring of lesion severity were performed on all animals. Based on the prevalence and extent of histopathological lesions, bronchoalveolar lavage cell numbers, neutrophil differential cell counts and the isolation of M. pulmonis, the most severe disease occurred in the groups that received both agents. There was no significant difference in lesion severity between the groups receiving both agents other than in those examined during the acute stages of SDAV infection. Based on these results, it is evident that SDAV enhances lower respiRatory tract disease in Wistar Rats whether exposure occurs at one week prior to or at various intervals following M. pulmonis infections.
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Preliminary characterization of the structural proteins of the Coronaviruses, sialodacryoadenitis virus and Parker's Rat Coronavirus.
Canadian journal of veterinary research = Revue canadienne de recherche veterinaire, 1994Co-Authors: Michael G. Barker, D. H. Percy, D J Hovland, J. I. MacinnesAbstract:A procedure was developed for the partial purification of the Rat Coronaviruses, sialodacryoadenitis virus (SDAV) and Parker's Rat Coronavirus (PRC). The SDAV and PRC were replicated in L-2 cell monolayer cultures, precipitated with ammonium sulphate, and further concentRated using sucrose density gradient centrifugation. The major SDAV and PRC proteins were identified by immunoblotting and compared with those of the JHM strain of mouse hepatitis virus (MHV-JHM). Monoclonal antibodies (MAb) against the M protein of JHM recognized proteins interpreted to be slightly smaller in immunoblots of SDAV and PRC (22.8 vs 23K for JHM). Similarly, a monoclonal antibody against the JHM N protein reacted with proteins of 53K in SDAV and PRC (vs 56 K for JHM). Polyclonal antisera to all three viruses also cross-reacted with the M and N proteins. Some cross-reactivity amongst the S proteins was observed. Based on these data, the structural proteins of the Rat Coronaviruses, SDAV and PRC are closely related to those of MHV-JHM.
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Coronavirus infections in the laboRatory Rat: degree of cross protection following immunization with a heterologous strain.
Canadian journal of veterinary research = Revue canadienne de recherche veterinaire, 1994Co-Authors: C G Bihun, D. H. PercyAbstract:Abstract One hundred and twenty-one specific pathogen-free male Wistar Rats eight to ten weeks of age were used to evaluate the efficacy of Parker's Rat Coronavirus (PRC) in affording cross protection on subsequent challenge with virulent sialodacryoadenitis (SDA) virus. Sixty-two animals were inoculated intranasally on day 0 and 21 days later with approximately 10(2) median tissue culture infective doses (TCID50) of the tenth passage of PRC replicated in L-2 cells. Animals were selected at random postvaccination to evaluate the safety and efficacy of PRC by histopathology, immunohistochemistry and serology. At three and six months postvaccination (PV), vaccinated and seronegative control Rats were inoculated intranasally with approximately 10(3) TCID50 doses of virulent SDA virus. Challenged Rats were then killed at 6, 10 and 14 days postchallenge and necropsied. Evaluations were based on lesion indices in lacrimal and salivary glands and respiRatory tract, the presence of viral antigen by immunohistochemistry, and antibody response. Lesions were observed in Rats killed PV, but in general, they were significantly reduced compared with those present in seronegative animals post-exposure to virulent SDA virus (p < or = 0.05). However, they were still considered to be an unacceptable level for a routine vaccination procedure. Potvaccination antibody titers to Rat Coronavirus were evident in all animals tested at three or six months prior to challenge with SDA virus.(ABSTRACT TRUNCATED AT 250 WORDS)
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A comparison of the sensitivity and specificity of sialodacryoadenitis virus, Parker's Rat Coronavirus, and mouse hepatitis virus-infected cells as a source of antigen for the detection of antibody to Rat Coronaviruses
Archives of Virology, 1991Co-Authors: D. H. Percy, K. L. Williams, F. X. PaturzoAbstract:Sialodacryoadenitis virus (SDAV) and Parker's Rat Coronavirus (PRC) are two recognized viral strains which cause spontaneous disease in the laboRatory Rat. Currently there is no recognized practical procedure which will accuRately differentiate infections with these strains. Using SDAV- and PRC-infected L-2 cells as the source of antigen, and sera from Rats collected post inoculation with either of these viral strains, the indirect fluorescent antibody (IFA) procedure was used to determine whether antibody titers could be used to differentiate infections from the homologous and heterologous virus. There was no detectable difference in the sensitivity or specificity of these systems in detecting antibody to the homologous or heterologous virus. Thus there was no evidence that SDAV- and PRC-infected cells would serve to differentiate antibody to the homologous virus using the IFA technique. In addition, antibody titers were similar when mouse hepatitis virus (MHV)-infected cells were used as the source of antigen for the IFA technique. However, using MHV or SDAV-infected cells as the source of antigen, there was a significant difference in antibody titers to the homologous virus detected using the immunoenzyme technique.
