The Experts below are selected from a list of 2970 Experts worldwide ranked by ideXlab platform
Stefan Pohlmann - One of the best experts on this subject based on the ideXlab platform.
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mutations in the spike protein of middle east respiratory syndrome coronavirus transmitted in korea increase resistance to antibody mediated neutralization
Journal of Virology, 2018Co-Authors: Marcel A. Müller, Stefan Pohlmann, Hannah Kleineweber, Mahmoud Tarek Elzayat, Lingshu Wang, Barney S Graham, Christian Drosten, Markus HoffmannAbstract:ABSTRACT Middle East respiratory syndrome coronavirus (MERS-CoV) poses a threat to public health. The virus is endemic in the Middle East but can be transmitted to other countries by travel activity. The introduction of MERS-CoV into the Republic of Korea by an infected traveler resulted in a hospital outbreak of MERS that entailed 186 cases and 38 deaths. The MERS-CoV spike (S) protein binds to the cellular protein DPP4 via its Receptor binding domain (RBD) and mediates Viral entry into target cells. During the MERS outbreak in Korea, emergence and spread of Viral variants that harbored mutations in the RBD, D510G and I529T, was observed. Counterintuitively, these mutations were found to reduce DPP4 binding and Viral entry into target cells. In this study, we investigated whether they also exerted proViral effects. We confirm that changes D510G and I529T reduce S protein binding to DPP4 but show that this reduction only translates into diminished Viral entry when expression of DPP4 on target cells is low. Neither mutation modulated S protein binding to sialic acids, S protein activation by host cell proteases, or inhibition of S protein-driven entry by interferon-induced transmembrane proteins. In contrast, changes D510G and I529T increased resistance of S protein-driven entry to neutralization by monoclonal antibodies and sera from MERS patients. These findings indicate that MERS-CoV variants with reduced neutralization sensitivity were transmitted during the Korean outbreak and that the responsible mutations were compatible with robust infection of cells expressing high levels of DPP4. IMPORTANCE MERS-CoV has pandemic potential, and it is important to identify mutations in Viral proteins that might augment Viral spread. In the course of a large hospital outbreak of MERS in the Republic of Korea in 2015, the spread of a Viral variant that contained mutations in the Viral spike protein was observed. These mutations were found to reduce Receptor binding and Viral infectivity. However, it remained unclear whether they also exerted proViral effects. We demonstrate that these mutations reduce sensitivity to antibody-mediated neutralization and are compatible with robust infection of target cells expressing large amounts of the Viral Receptor DPP4.
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tmprss2 and adam17 cleave ace2 differentially and only proteolysis by tmprss2 augments entry driven by the severe acute respiratory syndrome coronavirus spike protein
Journal of Virology, 2014Co-Authors: Adeline Heurich, Heike Hofmannwinkler, Stefanie Gierer, Thomas Liepold, Olaf Jahn, Stefan PohlmannAbstract:The type II transmembrane serine proteases TMPRSS2 and HAT can cleave and activate the spike protein (S) of the severe acute respiratory syndrome coronavirus (SARS-CoV) for membrane fusion. In addition, these proteases cleave the Viral Receptor, the carboxypeptidase angiotensin-converting enzyme 2 (ACE2), and it was proposed that ACE2 cleavage augments Viral infectivity. However, no mechanistic insights into this process were obtained and the relevance of ACE2 cleavage for SARS-CoV S protein (SARS-S) activation has not been determined. Here, we show that arginine and lysine residues within ACE2 amino acids 697 to 716 are essential for cleavage by TMPRSS2 and HAT and that ACE2 processing is required for augmentation of SARS-S-driven entry by these proteases. In contrast, ACE2 cleavage was dispensable for activation of the Viral S protein. Expression of TMPRSS2 increased cellular uptake of soluble SARS-S, suggesting that protease-dependent augmentation of Viral entry might be due to increased uptake of virions into target cells. Finally, TMPRSS2 was found to compete with the metalloprotease ADAM17 for ACE2 processing, but only cleavage by TMPRSS2 resulted in augmented SARS-S-driven entry. Collectively, our results in conjunction with those of previous studies indicate that TMPRSS2 and potentially related proteases promote SARS-CoV entry by two separate mechanisms: ACE2 cleavage, which might promote Viral uptake, and SARS-S cleavage, which activates the S protein for membrane fusion. These observations have interesting implications for the development of novel therapeutics. In addition, they should spur efforts to determine whether Receptor cleavage promotes entry of other coronaviruses, which use peptidases as entry Receptors.
Stephanie Bertram - One of the best experts on this subject based on the ideXlab platform.
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cleavage and activation of the severe acute respiratory syndrome coronavirus spike protein by human airway trypsin like protease
Journal of Virology, 2011Co-Authors: Ilona Glowacka, Hayley Lavender, Kerstin Gnirss, Inga Nehlmeier, Yuxian He, Daniela Niemeyer, Stephanie Bertram, Marcel A. Müller, Graham SimmonsAbstract:The highly pathogenic severe acute respiratory syndrome coronavirus (SARS-CoV) poses a constant threat to human health. The Viral spike protein (SARS-S) mediates host cell entry and is a potential target for antiViral intervention. Activation of SARS-S by host cell proteases is essential for SARS-CoV infectivity but remains incompletely understood. Here, we analyzed the role of the type II transmembrane serine proteases (TTSPs) human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2), in SARS-S activation. We found that HAT activates SARS-S in the context of surrogate systems and authentic SARS-CoV infection and is coexpressed with the Viral Receptor angiotensin-converting enzyme 2 (ACE2) in bronchial epithelial cells and pneumocytes. HAT cleaved SARS-S at R667, as determined by mutagenesis and mass spectrometry, and activated SARS-S for cell-cell fusion in cis and trans, while the related pulmonary protease TMPRSS2 cleaved SARS-S at multiple sites and activated SARS-S only in trans. However, TMPRSS2 but not HAT expression rendered SARS-S-driven virus-cell fusion independent of cathepsin activity, indicating that HAT and TMPRSS2 activate SARS-S differentially. Collectively, our results show that HAT cleaves and activates SARS-S and might support Viral spread in patients.
Graham Simmons - One of the best experts on this subject based on the ideXlab platform.
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cleavage and activation of the severe acute respiratory syndrome coronavirus spike protein by human airway trypsin like protease
Journal of Virology, 2011Co-Authors: Ilona Glowacka, Hayley Lavender, Kerstin Gnirss, Inga Nehlmeier, Yuxian He, Daniela Niemeyer, Stephanie Bertram, Marcel A. Müller, Graham SimmonsAbstract:The highly pathogenic severe acute respiratory syndrome coronavirus (SARS-CoV) poses a constant threat to human health. The Viral spike protein (SARS-S) mediates host cell entry and is a potential target for antiViral intervention. Activation of SARS-S by host cell proteases is essential for SARS-CoV infectivity but remains incompletely understood. Here, we analyzed the role of the type II transmembrane serine proteases (TTSPs) human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2), in SARS-S activation. We found that HAT activates SARS-S in the context of surrogate systems and authentic SARS-CoV infection and is coexpressed with the Viral Receptor angiotensin-converting enzyme 2 (ACE2) in bronchial epithelial cells and pneumocytes. HAT cleaved SARS-S at R667, as determined by mutagenesis and mass spectrometry, and activated SARS-S for cell-cell fusion in cis and trans, while the related pulmonary protease TMPRSS2 cleaved SARS-S at multiple sites and activated SARS-S only in trans. However, TMPRSS2 but not HAT expression rendered SARS-S-driven virus-cell fusion independent of cathepsin activity, indicating that HAT and TMPRSS2 activate SARS-S differentially. Collectively, our results show that HAT cleaves and activates SARS-S and might support Viral spread in patients.
Gary J. Nabel - One of the best experts on this subject based on the ideXlab platform.
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Structural analyses at pseudo atomic resolution of Chikungunya virus and antibodies show mechanisms of neutralization.
eLife, 2013Co-Authors: Siyang Sun, Gary J. Nabel, Ye Xiang, Wataru Akahata, Heather A. Holdaway, Pankaj Pal, Xinzheng Zhang, Michael S. Diamond, Michael G. RossmannAbstract:The Chikungunya virus is carried by mosquitos and can cause a number of diseases in humans including encephalitis, which can be fatal in some cases, and severe arthritis. A recent mutation in the E1 protein of the virus has allowed it to efficiently reproduce in a different species of mosquitos, leading to a Chikungunya epidemic in Reunion Island in 2005 and the subsequent infection of millions of individuals in Africa and Asia. The virus also has the potential to spread to many areas of Europe and the Americas. Chikungunya virus has a single-stranded RNA genome that codes for four non-structural proteins and five structural proteins. Based on this knowledge it has been possible to develop virus-like particles that can be used to immunise non-human primates against Chikungunya infection by inducing antibody production. However, the development of vaccines for Chikungunya in humans will require a deeper understanding of how these antibodies produced by the vaccine interact with the virus and more detailed information about the structures of the virus and antibodies. Sun et al. have used two techniques – X-ray crystallography and electron cryo-microscopy – to determine the structure of Chikungunya virus-like particles, and to obtain new insights into the interactions of these particles with four related antibodies. Electron cryo-microscopy was used to figure out the structure of the particles at near atomic resolution, and X-ray crystallography was used to determine the atomic resolution structures of two of the four Fab antibodies that neutralize the Chikungunya virus. Electron cryo-microscopy was also used to probe the complex formed by the interactions between the virus-like particles and the antibodies. Sun et al. were able to identify the likely Viral Receptor site that is blocked by three of the antibodies when they neutralize the virus; the fourth antibody is thought to act by immobilizing one of the domains of protein E2, thereby hiding the “fusion loop” that allows the virus to enter and infect human tissue. It is hoped that these findings will contribute to efforts to combat the spread of the Chikungunya virus worldwide.
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evasion of antibody neutralization in emerging severe acute respiratory syndrome coronaviruses
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Zhiyong Yang, Heidi C Werner, Wingpui Kong, Elisabetta Traggiai, Kwanyee Leung, Antonio Lanzavecchia, Gary J. NabelAbstract:Molecular characterization of the severe acute respiratory syndrome coronavirus has revealed genetic diversity among isolates. The spike (S) glycoprotein, the major target for vaccine and immune therapy, shows up to 17 substitutions in its 1,255-aa sequence; however, the biologic significance of these changes is unknown. Here, the functional effects of S mutations have been determined by analyzing their affinity for a Viral Receptor, human angiotensin-converting enzyme 2 (hACE-2), and their sensitivity to Ab neutralization with Viral pseudotypes. Although minor differences among eight strains transmitted during human outbreaks in early 2003 were found, substantial functional changes were detected in S derived from a case in late 2003 from Guangdong province [S(GD03T0013)] and from two palm civets, S(SZ3) and S(SZ16). S(GD03T0013) depended less on the hACE-2 Receptor and was markedly resistant to Ab inhibition. Unexpectedly, Abs that neutralized most human S glycoproteins enhanced entry mediated by the civet virus S glycoproteins. The mechanism of enhancement involved the interaction of Abs with conformational epitopes in the hACE-2-binding domain. Finally, improved immunogens and mAbs that minimize this complication have been defined. These data show that the entry of severe acute respiratory syndrome coronaviruses can be enhanced by Abs, and they underscore the need to address the evolving diversity of this newly emerged virus for vaccines and immune therapies.
Marcel A. Müller - One of the best experts on this subject based on the ideXlab platform.
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mutations in the spike protein of middle east respiratory syndrome coronavirus transmitted in korea increase resistance to antibody mediated neutralization
Journal of Virology, 2018Co-Authors: Marcel A. Müller, Stefan Pohlmann, Hannah Kleineweber, Mahmoud Tarek Elzayat, Lingshu Wang, Barney S Graham, Christian Drosten, Markus HoffmannAbstract:ABSTRACT Middle East respiratory syndrome coronavirus (MERS-CoV) poses a threat to public health. The virus is endemic in the Middle East but can be transmitted to other countries by travel activity. The introduction of MERS-CoV into the Republic of Korea by an infected traveler resulted in a hospital outbreak of MERS that entailed 186 cases and 38 deaths. The MERS-CoV spike (S) protein binds to the cellular protein DPP4 via its Receptor binding domain (RBD) and mediates Viral entry into target cells. During the MERS outbreak in Korea, emergence and spread of Viral variants that harbored mutations in the RBD, D510G and I529T, was observed. Counterintuitively, these mutations were found to reduce DPP4 binding and Viral entry into target cells. In this study, we investigated whether they also exerted proViral effects. We confirm that changes D510G and I529T reduce S protein binding to DPP4 but show that this reduction only translates into diminished Viral entry when expression of DPP4 on target cells is low. Neither mutation modulated S protein binding to sialic acids, S protein activation by host cell proteases, or inhibition of S protein-driven entry by interferon-induced transmembrane proteins. In contrast, changes D510G and I529T increased resistance of S protein-driven entry to neutralization by monoclonal antibodies and sera from MERS patients. These findings indicate that MERS-CoV variants with reduced neutralization sensitivity were transmitted during the Korean outbreak and that the responsible mutations were compatible with robust infection of cells expressing high levels of DPP4. IMPORTANCE MERS-CoV has pandemic potential, and it is important to identify mutations in Viral proteins that might augment Viral spread. In the course of a large hospital outbreak of MERS in the Republic of Korea in 2015, the spread of a Viral variant that contained mutations in the Viral spike protein was observed. These mutations were found to reduce Receptor binding and Viral infectivity. However, it remained unclear whether they also exerted proViral effects. We demonstrate that these mutations reduce sensitivity to antibody-mediated neutralization and are compatible with robust infection of target cells expressing large amounts of the Viral Receptor DPP4.
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cleavage and activation of the severe acute respiratory syndrome coronavirus spike protein by human airway trypsin like protease
Journal of Virology, 2011Co-Authors: Ilona Glowacka, Hayley Lavender, Kerstin Gnirss, Inga Nehlmeier, Yuxian He, Daniela Niemeyer, Stephanie Bertram, Marcel A. Müller, Graham SimmonsAbstract:The highly pathogenic severe acute respiratory syndrome coronavirus (SARS-CoV) poses a constant threat to human health. The Viral spike protein (SARS-S) mediates host cell entry and is a potential target for antiViral intervention. Activation of SARS-S by host cell proteases is essential for SARS-CoV infectivity but remains incompletely understood. Here, we analyzed the role of the type II transmembrane serine proteases (TTSPs) human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2), in SARS-S activation. We found that HAT activates SARS-S in the context of surrogate systems and authentic SARS-CoV infection and is coexpressed with the Viral Receptor angiotensin-converting enzyme 2 (ACE2) in bronchial epithelial cells and pneumocytes. HAT cleaved SARS-S at R667, as determined by mutagenesis and mass spectrometry, and activated SARS-S for cell-cell fusion in cis and trans, while the related pulmonary protease TMPRSS2 cleaved SARS-S at multiple sites and activated SARS-S only in trans. However, TMPRSS2 but not HAT expression rendered SARS-S-driven virus-cell fusion independent of cathepsin activity, indicating that HAT and TMPRSS2 activate SARS-S differentially. Collectively, our results show that HAT cleaves and activates SARS-S and might support Viral spread in patients.
