The Experts below are selected from a list of 999 Experts worldwide ranked by ideXlab platform
Heinz Feldmann - One of the best experts on this subject based on the ideXlab platform.
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Pathogenicity of Ebola and Marburg Viruses Is Associated With Differential Activation of the Myeloid Compartment in Humanized Triple Knockout-Bone Marrow, Liver, and Thymus Mice.
The Journal of infectious diseases, 2018Co-Authors: Kerry J. Lavender, Heinz Feldmann, Brandi N. Williamson, Greg Saturday, Cynthia Martellaro, Amanda J. Griffin, Kim J. Hasenkrug, Joseph PrescottAbstract:Ebola virus (EBOV) and Marburg virus (MARV) outbreaks are highly lethal, and Infection results in a hemorrhagic fever with complex etiology. These zoonotic viruses dysregulate the immune system to cause disease, in part by replicating within myeloid cells that would normally innately control viral Infection and shape the adaptive immune response. We used triple knockout (TKO)-bone marrow, liver, thymus (BLT) humanized mice to recapitulate the early in vivo human immune response to Filovirus Infection. Disease severity in TKO-BLT mice was dissimilar between EBOV and MARV with greater severity observed during EBOV Infection. Disease severity was related to increased Kupffer cell Infection in the liver, higher levels of myeloid dysfunction, and skewing of macrophage subtypes in EBOV compared with MARV-infected mice. Overall, the TKO-BLT model provided a practical in vivo platform to study the human immune response to Filovirus Infection and generated a better understanding of how these viruses modulate specific components of the immune system.
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considerations in the use of nonhuman primate models of ebola virus and marburg virus Infection
The Journal of Infectious Diseases, 2015Co-Authors: Thomas W Geisbert, James E Strong, Heinz FeldmannAbstract:Abstract The Filoviruses, Ebola virus and Marburg virus, are zoonotic pathogens that cause severe hemorrhagic fever in humans and nonhuman primates (NHPs), with case-fatality rates ranging from 23% to 90%. The current outbreak of Ebola virus Infection in West Africa, with >26 000 cases, demonstrates the long-underestimated public health danger that Filoviruses pose as natural human pathogens. Currently, there are no vaccines or treatments licensed for human use. Licensure of any medical countermeasure may require demonstration of efficacy in the gold standard cynomolgus or rhesus macaque models of Filovirus Infection. Substantial progress has been made over the last decade in characterizing the Filovirus NHP models. However, there is considerable debate over a variety of experimental conditions, including differences among Filovirus isolates used, routes and doses of exposure, and euthanasia criteria, all of which may contribute to variability of results among different laboratories. As an example of the importance of understanding these differences, recent data with Ebola virus shows that an addition of a single uridine residue in the glycoprotein gene at the editing site attenuates the virus. Here, we draw on decades of experience working with Filovirus-infected NHPs to provide a perspective on the importance of various experimental conditions.
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durability of a vesicular stomatitis virus based marburg virus vaccine in nonhuman primates
PLOS ONE, 2014Co-Authors: Chad E Mire, Heinz Feldmann, Lisa E Hensley, Joan B Geisbert, Krystle N Agans, Benjamin A Satterfield, Krista Versteeg, Elizabeth A Fritz, Thomas W GeisbertAbstract:The Filoviruses, Marburg virus (MARV) and Ebola virus, causes severe hemorrhagic fever with high mortality in humans and nonhuman primates. A promising Filovirus vaccine under development is based on a recombinant vesicular stomatitis virus (rVSV) that expresses individual Filovirus glycoproteins (GPs) in place of the VSV glycoprotein (G). These vaccines have shown 100% efficacy against Filovirus Infection in nonhuman primates when challenge occurs 28–35 days after a single injection immunization. Here, we examined the ability of a rVSV MARV-GP vaccine to provide protection when challenge occurs more than a year after vaccination. Cynomolgus macaques were immunized with rVSV-MARV-GP and challenged with MARV approximately 14 months after vaccination. Immunization resulted in the vaccine cohort of six animals having anti-MARV GP IgG throughout the pre-challenge period. Following MARV challenge none of the vaccinated animals showed any signs of clinical disease or viremia and all were completely protected from MARV Infection. Two unvaccinated control animals exhibited signs consistent with MARV Infection and both succumbed. Importantly, these data are the first to show 100% protective efficacy against any high dose Filovirus challenge beyond 8 weeks after final vaccination. These findings demonstrate the durability of VSV-based Filovirus vaccines.
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Novel neutralizing monoclonal antibodies protect rodents against lethal Filovirus challenges
Trials in Vaccinology, 2014Co-Authors: Caleb D. Marceau, Andrea Marzi, Heinz Feldmann, Surendra Negi, Humberto Hernandez, Julie Callison, Viktoriya Borisevich, Werner Braun, Jody D. Berry, Barry RockxAbstract:Filoviruses are the causative agents of lethal hemorrhagic fever in human and non-human primates (NHP). The family of Filoviridae is composed of three genera, Ebolavirus, Marburgvirus and Cuevavirus. There are currently no approved vaccines or antiviral therapeutics for the treatment of Filovirus Infections in humans. Passive transfer of neutralizing antibodies targeting the Ebola virus (EBOV) glycoprotein (GP) has proven effective in protecting mice, guinea pigs and NHP from lethal challenges with EBOV. In this study, we generated two neutralizing monoclonal antibodies (MAbs), termed S9 and M4 that recognize the GP of EBOV or multiple strains of Marburg virus (MARV), respectively. We characterized the putative binding site of S9 as a linear epitope on the glycan cap of the GP1 subunit of the EBOV-GP. The M4 antibody recognizes an unknown conformational epitope on MARV-GP. Additionally, we demonstrated the post-exposure protection potential of these antibodies in both the mouse and guinea pig models of Filovirus Infection. These data indicate that MAbs S9 and M4 would be good candidates for inclusion in an antibody cocktail for the treatment of Filovirus Infections.
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detection of all known Filovirus species by reverse transcription polymerase chain reaction using a primer set specific for the viral nucleoprotein gene
Journal of Virological Methods, 2011Co-Authors: Hideki Ebihara, Heinz Feldmann, Hiroko Miyamoto, Hirohito Ogawa, Shigeru Morikawa, Ayato TakadaAbstract:The Filoviruses, Marburg virus (MARV) and Ebola virus (EBOV), are causative agents of severe hemorrhagic fever with high mortality rates in humans and non-human primates. Sporadic outbreaks of Filovirus Infection have occurred in Central Africa and parts of Asia. Identification of the natural reservoir animals that are unknown yet and epidemiological investigations are current challenges to forestall outbreaks of Filovirus diseases. The Filovirus species identified currently include one in the MARV group and five in the EBOV group, with large genetic variations found among the species. Therefore, it has been difficult to develop a single sensitive assay to detect all Filovirus species, which would advance laboratory diagnosis greatly in endemic areas. In this study, a highly sensitive universal RT-PCR assay targeting the nucleoprotein (NP) gene of Filoviruses was developed. The genomic RNAs of all known MARV and EBOV species were detected by using an NP-specific primer set. In addition, this RT-PCR procedure was verified further for its application to detect viral RNAs in tissue samples of animals infected experimentally and blood specimens of infected patients. This assay will be a useful method for diagnostics and epidemiological studies of Filovirus Infections.
Sina Bavari - One of the best experts on this subject based on the ideXlab platform.
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identification of a coumarin based antihistamine like small molecule as an anti filoviral entry inhibitor
Antiviral Research, 2017Co-Authors: Han Cheng, Sina Bavari, Norton P Peet, Adam Schafer, Veronica Soloveva, Dima N Gharaibeh, Tara Kenny, Cary Retterer, Rouzbeh Zamani, Lijun RongAbstract:Filoviruses, consisting of Ebola virus, Marburg virus and Cuevavirus, cause severe hemorrhagic fevers in humans with high mortality rates up to 90%. Currently, there is no approved vaccine or therapy available for the prevention and treatment of Filovirus Infection in humans. The recent 2013-2015 West African Ebola epidemic underscores the urgency to develop antiviral therapeutics against these infectious diseases. Our previous study showed that GPCR antagonists, particularly histamine receptor antagonists (antihistamines) inhibit Ebola and Marburg virus entry. In this study, we screened a library of 1220 small molecules with predicted antihistamine activity, identified multiple compounds with potent inhibitory activity against entry of both Ebola and Marburg viruses in human cancer cell lines, and confirmed their anti-Ebola activity in human primary cells. These small molecules target a late-stage of Ebola virus entry. Further structure-activity relationship studies around one compound (cp19) reveal the importance of the coumarin fused ring structure, especially the hydrophobic substituents at positions 3 and/or 4, for its antiviral activity, and this identified scaffold represents a favorable starting point for the rapid development of anti-Filovirus therapeutic agents.
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Ebola virus glycoprotein fc fusion protein confers protection against lethal challenge in vaccinated mice. Vaccine 2011
2015Co-Authors: Krishnamurthy Konduru, Steven B. Bradfute, Steven C. Wood, Jerome Jacques, Siham Nakamura, Sufi Morshed, Sina Bavari, Gerardo G. KaplanAbstract:Ebola virus is a Filoviridae that causes hemorrhagic fever in humans and induces high morbidity and mortality rates. Filoviruses are classified as "Category A bioterrorism agents", and currently there are no licensed therapeutics or vaccines to treat and prevent Infection. The Filovirus glycoprotein (GP) is sufficient to protect individuals against Infection, and several vaccines based on GP are under development including recombinant adenovirus, parainfluenza virus, Venezuelan equine encephalitis virus, vesicular stomatitis virus (VSV) and virus-like particles. Here we describe the development of a GP Fc fusion protein as a vaccine candidate. We expressed the extracellular domain of the Zaire Ebola virus (ZEBOV) GP fused to the Fc fragment of human IgG1 (ZEBOVGP-Fc) in mammalian cells and showed that GP undergoes the complex furin cleavage and processing observed in the native membrane-bound GP. Mice immunized with ZEBOVGP-Fc developed T-cell immunity against ZEBOV GP and neutralizing antibodies against replication-competent VSV-G deleted recombinant VSV containing ZEBOV GP. The ZEBOVGP-Fc vaccinated mice were protected against challenge with a lethal dose of ZEBOV. These results show that vaccination with the ZEBOVGP-Fc fusion protein alone without the need of a viral vector or assembly into virus-like particles is sufficient to induce protective immunity against ZEBOV in mice. Our data suggested that Filovirus GP Fc fusion proteins could be developed as a simple, safe, efficacious, and cost effective vaccine against Filovirus Infection for human use. 1
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Shedding Light on Filovirus Infection with High-Content Imaging
Viruses, 2012Co-Authors: Gianluca Pegoraro, Sina Bavari, Rekha G. PanchalAbstract:Microscopy has been instrumental in the discovery and characterization of microorganisms. Major advances in high-throughput fluorescence microscopy and automated, high-content image analysis tools are paving the way to the systematic and quantitative study of the molecular properties of cellular systems, both at the population and at the single-cell level. High-Content Imaging (HCI) has been used to characterize host-virus interactions in genome-wide reverse genetic screens and to identify novel cellular factors implicated in the binding, entry, replication and egress of several pathogenic viruses. Here we present an overview of the most significant applications of HCI in the context of the cell biology of Filovirus Infection. HCI assays have been recently implemented to quantitatively study Filoviruses in cell culture, employing either infectious viruses in a BSL-4 environment or surrogate genetic systems in a BSL-2 environment. These assays are becoming instrumental for small molecule and siRNA screens aimed at the discovery of both cellular therapeutic targets and of compounds with anti-viral properties. We discuss the current practical constraints limiting the implementation of high-throughput biology in a BSL-4 environment, and propose possible solutions to safely perform high-content, high-throughput Filovirus Infection assays. Finally, we discuss possible novel applications of HCI in the context of Filovirus research with particular emphasis on the identification of possible cellular biomarkers of virus Infection.
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Therapeutics for Filovirus Infection: traditional approaches and progress towards in silico drug design.
Expert Opinion on Drug Discovery, 2012Co-Authors: Amy C. Shurtleff, Tam Luong Nguyen, David A Kingery, Sina BavariAbstract:Introduction: Ebolaviruses and marburgviruses cause severe and often lethal human hemorrhagic fevers. As no FDA-approved therapeutics are available for these Infections, efforts to discover new therapeutics are important, especially because these pathogens are considered biothreats and emerging infectious diseases. All methods for discovering new therapeutics should be considered, including compound library screening in vitro against virus and in silico structure-based drug design, where possible, if sufficient biochemical and structural information is available. Areas covered: This review covers the structure and function of Filovirus proteins, as they have been reported to date, as well as some of the current antiviral screening approaches. The authors discuss key studies mapping small-molecule modulators that were found through library and in silico screens to potential sites on viral proteins or host proteins involved in virus trafficking and pathogenesis. A description of ebolavirus and marburgvirus ...
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Correlates of Immunity to Filovirus Infection
Viruses, 2011Co-Authors: Steven B. Bradfute, Sina BavariAbstract:Filoviruses can cause severe, often fatal hemorrhagic fever in humans. Recent advances in vaccine and therapeutic drug development have provided encouraging data concerning treatment of these Infections. However, relatively little is known about immune responses in fatal versus non-fatal Filovirus Infection. This review summarizes the published literature on correlates of immunity to Filovirus Infection, and highlights deficiencies in our knowledge on this topic. It is likely that there are several types of successful immune responses, depending on the type of Filovirus, and the presence and timing of vaccination or drug treatment.
Reiko Yoshida - One of the best experts on this subject based on the ideXlab platform.
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A biaryl sulfonamide derivative as a novel inhibitor of Filovirus Infection
Antiviral research, 2020Co-Authors: Mao Isono, Masahiro Kajihara, Reiko Yoshida, Makoto Kuroda, Tatsunari Kondoh, Rashid Manzoor, Wakako Furuyama, Manabu Igarashi, Kosuke Okuya, Hiroko MiyamotoAbstract:Abstract Ebolaviruses and marburgviruses, members of the family Filoviridae, are known to cause fatal diseases often associated with hemorrhagic fever. Recent outbreaks of Ebola virus disease in West African countries and the Democratic Republic of the Congo have made clear the urgent need for the development of therapeutics and vaccines against Filoviruses. Using replication-incompetent vesicular stomatitis virus (VSV) pseudotyped with the Ebola virus (EBOV) envelope glycoprotein (GP), we screened a chemical compound library to obtain new drug candidates that inhibit filoviral entry into target cells. We discovered a biaryl sulfonamide derivative that suppressed in vitro Infection mediated by GPs derived from all known human-pathogenic Filoviruses. To determine the inhibitory mechanism of the compound, we monitored each entry step (attachment, internalization, and membrane fusion) using lipophilic tracer-labeled ebolavirus-like particles and found that the compound efficiently blocked fusion between the viral envelope and the endosomal membrane during cellular entry. However, the compound did not block the interaction of GP with the Niemann-Pick C1 protein, which is believed to be the receptor of Filoviruses. Using replication-competent VSVs pseudotyped with EBOV GP, we selected escape mutants and identified two EBOV GP amino acid residues (positions 47 and 66) important for the interaction with this compound. Interestingly, these amino acid residues were located at the base region of the GP trimer, suggesting that the compound might interfere with the GP conformational change required for membrane fusion. These results suggest that this biaryl sulfonamide derivative is a novel fusion inhibitor and a possible drug candidate for the development of a pan-Filovirus therapeutic.
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Seroprevalence of Filovirus Infection of Rousettus aegyptiacus Bats in Zambia.
The Journal of Infectious Diseases, 2018Co-Authors: Katendi Changula, Masahiro Kajihara, Bernard M. Hang’ombe, Reiko Yoshida, Akina Mori-kajihara, Yoshiki Eto, Hiroko Miyamoto, Asako Shigeno, Yongjin Qiu, Daniel MwizabiAbstract:Bats are suspected to play important roles in the ecology of Filoviruses, including ebolaviruses and marburgviruses. A cave-dwelling fruit bat, Rousettus aegyptiacus, has been shown to be a reservoir of marburgviruses. Using an enzyme-linked immunosorbent assay with the viral glycoprotein antigen, we detected immunoglobulin G antibodies specific to multiple Filoviruses in 158 of 290 serum samples of R aegyptiacus bats captured in Zambia during the years 2014-2017. In particular, 43.8% of the bats were seropositive to marburgvirus, supporting the notion that this bat species continuously maintains marburgviruses as a reservoir. Of note, distinct peaks of seropositive rates were repeatedly observed at the beginning of rainy seasons, suggesting seasonality of the presence of newly infected individuals in this bat population. These data highlight the need for continued monitoring of Filovirus Infection in this bat species even in countries where Filovirus diseases have not been reported.
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Interaction between TIM-1 and NPC1 Is Important for Cellular Entry of Ebola Virus
Journal of virology, 2015Co-Authors: Makoto Kuroda, Andrea Marzi, Masahiro Kajihara, Hiroko Miyamoto, Daisuke Fujikura, Osamu Noyori, Junki Maruyama, Asuka Nanbo, Keita Matsuno, Reiko YoshidaAbstract:Multiple host molecules are known to be involved in the cellular entry of Filoviruses, including Ebola virus (EBOV); T-cell immunoglobulin and mucin domain 1 (TIM-1) and Niemann-Pick C1 (NPC1) have been identified as attachment and fusion receptors, respectively. However, the molecular mechanisms underlying the entry process have not been fully understood. We found that TIM-1 and NPC1 colocalized and interacted in the intracellular vesicles where EBOV glycoprotein (GP)-mediated membrane fusion occurred. Interestingly, a TIM-1-specific monoclonal antibody (MAb), M224/1, prevented GP-mediated membrane fusion and also interfered with the binding of TIM-1 to NPC1, suggesting that the interaction between TIM-1 and NPC1 is important for Filovirus membrane fusion. Moreover, MAb M224/1 efficiently inhibited the cellular entry of viruses from all known Filovirus species. These data suggest a novel mechanism underlying Filovirus membrane fusion and provide a potential cellular target for antiviral compounds that can be universally used against Filovirus Infections. IMPORTANCE Filoviruses, including Ebola and Marburg viruses, cause rapidly fatal diseases in humans and nonhuman primates. There are currently no approved vaccines or therapeutics for Filovirus diseases. In general, the cellular entry step of viruses is one of the key mechanisms to develop antiviral strategies. However, the molecular mechanisms underlying the entry process of Filoviruses have not been fully understood. In this study, we demonstrate that TIM-1 and NPC1, which serve as attachment and fusion receptors for Filovirus entry, interact in the intracellular vesicles where Ebola virus GP-mediated membrane fusion occurs and that this interaction is important for Filovirus Infection. We found that Filovirus Infection and GP-mediated membrane fusion in cultured cells were remarkably suppressed by treatment with a TIM-1-specific monoclonal antibody that interfered with the interaction between TIM-1 and NPC1. Our data provide new insights for the development of antiviral compounds that can be universally used against Filovirus Infections.
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Seroepidemiological Prevalence of Multiple Species of Filoviruses in Fruit Bats (Eidolon helvum) Migrating in Africa.
The Journal of infectious diseases, 2015Co-Authors: Hirohito Ogawa, Eri Nakayama, Reiko Yoshida, Hiroko Miyamoto, Ichiro Nakamura, Hirofumi Sawa, Akihiro Ishii, Yuka Thomas, Emiko Nakagawa, Keita MatsunoAbstract:Fruit bats are suspected to be a natural reservoir of Filoviruses, including Ebola and Marburg viruses. Using an enzyme-linked immunosorbent assay based on the viral glycoprotein antigens, we detected Filovirus-specific immunoglobulin G antibodies in 71 of 748 serum samples collected from migratory fruit bats (Eidolon helvum) in Zambia during 2006-2013. Although antibodies to African Filoviruses (eg, Zaire ebolavirus) were most prevalent, some serum samples showed distinct specificity for Reston ebolavirus, which that has thus far been found only in Asia. Interestingly, the transition of Filovirus species causing outbreaks in Central and West Africa during 2005-2014 seemed to be synchronized with the change of the serologically dominant virus species in these bats. These data suggest the introduction of multiple species of Filoviruses in the migratory bat population and point to the need for continued surveillance of Filovirus Infection of wild animals in sub-Saharan Africa, including hitherto nonendemic countries.
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A polymorphism of the TIM-1 IgV domain: implications for the susceptibility to Filovirus Infection.
Biochemical and Biophysical Research Communications, 2014Co-Authors: Makoto Kuroda, Masahiro Kajihara, Reiko Yoshida, Hiroko Miyamoto, Daisuke Fujikura, Osamu Noyori, Junki Maruyama, Ayato TakadaAbstract:Filoviruses, including Ebola and Marburg viruses, cause severe hemorrhagic fever in humans and nonhuman primates with mortality rates of up to 90%. Human T-cell immunoglobulin and mucin domain 1 (TIM-1) is one of the host proteins that have been shown to promote Filovirus entry into cells. In this study, we cloned TIM-1 genes from three different African green monkey kidney cell lines (Vero E6, COS-1, and BSC-1) and found that TIM-1 of Vero E6 had a 23-amino acid deletion and 6 amino acid substitutions compared with those of COS-1 and BSC-1. Interestingly, Vero E6 TIM-1 had a greater ability to promote the infectivity of vesicular stomatitis viruses pseudotyped with Filovirus glycoproteins than COS-1-derived TIM-1. We further found that the increased ability of Vero E6 TIM-1 to promote virus infectivity was most likely due to a single amino acid difference between these TIM-1s. These results suggest that a polymorphism of the TIM-1 molecules is one of the factors that influence cell susceptibility to Filovirus Infection, providing a new insight into the molecular basis for the Filovirus host range.
Ayato Takada - One of the best experts on this subject based on the ideXlab platform.
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Host Cell Factors Involved in Filovirus Infection
Current Tropical Medicine Reports, 2015Co-Authors: Masahiro Kajihara, Ayato TakadaAbstract:Filoviruses (ebolaviruses and marburgviruses) cause severe hemorrhagic fever in humans and nonhuman primates with high mortality rates of up to 90 %. The latest epidemic of Ebola virus disease in Western African countries has underscored the urgent need for effective prophylactic and therapeutic interventions for this deadly infectious disease. However, neither approved prophylactics nor therapeutics are currently available for Filovirus diseases. Recent studies have been unveiling the molecular mechanisms underlying the Filovirus lifecycle, including cellular entry, egress, and the evasion from host immunity, suggesting possibilities to develop effective pan-Filovirus drugs.
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A polymorphism of the TIM-1 IgV domain: implications for the susceptibility to Filovirus Infection.
Biochemical and Biophysical Research Communications, 2014Co-Authors: Makoto Kuroda, Masahiro Kajihara, Reiko Yoshida, Hiroko Miyamoto, Daisuke Fujikura, Osamu Noyori, Junki Maruyama, Ayato TakadaAbstract:Filoviruses, including Ebola and Marburg viruses, cause severe hemorrhagic fever in humans and nonhuman primates with mortality rates of up to 90%. Human T-cell immunoglobulin and mucin domain 1 (TIM-1) is one of the host proteins that have been shown to promote Filovirus entry into cells. In this study, we cloned TIM-1 genes from three different African green monkey kidney cell lines (Vero E6, COS-1, and BSC-1) and found that TIM-1 of Vero E6 had a 23-amino acid deletion and 6 amino acid substitutions compared with those of COS-1 and BSC-1. Interestingly, Vero E6 TIM-1 had a greater ability to promote the infectivity of vesicular stomatitis viruses pseudotyped with Filovirus glycoproteins than COS-1-derived TIM-1. We further found that the increased ability of Vero E6 TIM-1 to promote virus infectivity was most likely due to a single amino acid difference between these TIM-1s. These results suggest that a polymorphism of the TIM-1 molecules is one of the factors that influence cell susceptibility to Filovirus Infection, providing a new insight into the molecular basis for the Filovirus host range.
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Differential potential for envelope glycoprotein-mediated steric shielding of host cell surface proteins among Filoviruses.
Virology, 2013Co-Authors: Osamu Noyori, Eri Nakayama, Masahiro Kajihara, Reiko Yoshida, Makoto Kuroda, Manabu Igarashi, Keita Matsuno, Norikazu Isoda, Ayato TakadaAbstract:The viral envelope glycoprotein (GP) is thought to play important roles in the pathogenesis of Filovirus Infection. It is known that GP expressed on the cell surface forms a steric shield over host proteins such as major histocompatibility complex class I and integrin β1, which may result in the disorder of cell-to-cell contacts and/or inhibition of the immune response. However, it is not clarified whether this phenomenon contributes to the pathogenicity of Filoviruses. In this study, we found that the steric shielding efficiency differed among Filovirus strains and was correlated with the difference in their relative pathogenicities. While the highly glycosylated mucin-like region of GP was indispensable, the differential shielding efficiency did not necessarily depend on the primary structure of the mucin-like region, suggesting the importance of the overall properties (e.g., flexibility and stability) of the GP molecule for efficient shielding of host proteins.
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detection of all known Filovirus species by reverse transcription polymerase chain reaction using a primer set specific for the viral nucleoprotein gene
Journal of Virological Methods, 2011Co-Authors: Hideki Ebihara, Heinz Feldmann, Hiroko Miyamoto, Hirohito Ogawa, Shigeru Morikawa, Ayato TakadaAbstract:The Filoviruses, Marburg virus (MARV) and Ebola virus (EBOV), are causative agents of severe hemorrhagic fever with high mortality rates in humans and non-human primates. Sporadic outbreaks of Filovirus Infection have occurred in Central Africa and parts of Asia. Identification of the natural reservoir animals that are unknown yet and epidemiological investigations are current challenges to forestall outbreaks of Filovirus diseases. The Filovirus species identified currently include one in the MARV group and five in the EBOV group, with large genetic variations found among the species. Therefore, it has been difficult to develop a single sensitive assay to detect all Filovirus species, which would advance laboratory diagnosis greatly in endemic areas. In this study, a highly sensitive universal RT-PCR assay targeting the nucleoprotein (NP) gene of Filoviruses was developed. The genomic RNAs of all known MARV and EBOV species were detected by using an NP-specific primer set. In addition, this RT-PCR procedure was verified further for its application to detect viral RNAs in tissue samples of animals infected experimentally and blood specimens of infected patients. This assay will be a useful method for diagnostics and epidemiological studies of Filovirus Infections.
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C-type lectins do not act as functional receptors for Filovirus entry into cells
Biochemical and biophysical research communications, 2010Co-Authors: Keita Matsuno, Hideki Ebihara, Andrea Marzi, Heinz Feldmann, Eri Nakayama, Tatsuro Irimura, Osamu Noyori, Ayato TakadaAbstract:Cellular C-type lectins have been reported to facilitate Filovirus Infection by binding to glycans on Filovirus glycoprotein (GP). However, it is not clearly known whether interaction between C-type lectins and GP mediates all the steps of virus entry (i.e., attachment, internalization, and membrane fusion). In this study, we generated vesicular stomatitis viruses pseudotyped with mutant GPs that have impaired structures of the putative receptor binding regions and thus reduced ability to infect the monkey kidney cells that are routinely used for virus propagation. We found that infectivities of viruses with the mutant GPs dropped in C-type lectin-expressing cells, parallel with those in the monkey kidney cells, whereas binding activities of these GPs to the C-type lectins were not correlated with the reduced infectivities. These results suggest that C-type lectin-mediated entry of Filoviruses requires other cellular molecule(s) that may be involved in virion internalization or membrane fusion.
Thomas W Geisbert - One of the best experts on this subject based on the ideXlab platform.
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Filovirus Infection induces an anti inflammatory state in rousettus bats
bioRxiv, 2020Co-Authors: Anitha D Jayaprakash, Adam J Ronk, Abhishek N Prasad, Matthew F Covington, Kathryn R Stein, Toni M Schwarz, Saboor Hekmaty, Karla A Fenton, Thomas W Geisbert, Christopher F BaslerAbstract:The Filoviruses Ebola (EBOV) and Marburg (MARV) cause severe disease in humans. In contrast, the Egyptian rousette bat (Rousettus aegyptiacus), a natural reservoir of MARV, exhibits a subclinical phenotype with limited MARV replication and nearly undetectable EBOV replication. Rousettus cell lines support replication of Filoviruses, however. To understand the bat-Filovirus interaction, transcriptomes of tissues from EBOV- and MARV-infected R. aegyptiacus bats were analyzed. While viral transcripts were only detected in liver, a systemic response was observed involving other tissues as well. By focusing on evolutionarily divergent (from human homologues) protein-coding genes, we identified novel transcriptional pathways that suggest infected bats exhibit impaired coagulation, vasodilation, aberrant iron regulation, and impaired complement system leading to muted antibody responses. Furthermore, a robust T-cell response and an anti-inflammatory state driven by M2 macrophages were identified. These processes likely control Infection and limit pathology. All data can be freely explored and downloaded through our tools (http://katahdin.girihlet.com/shiny/bat/).
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Ebola and Marburg virus Infection in bats induces a systemic response
2020Co-Authors: Anitha D Jayaprakash, Adam J Ronk, Abhishek N Prasad, Matthew F Covington, Kathryn R Stein, Toni M Schwarz, Saboor Hekmaty, Karla A Fenton, Thomas W Geisbert, Christopher F BaslerAbstract:Abstract The Filoviruses Ebola (EBOV) and Marburg (MARV) cause fatal disease in humans and nonhuman primates but are associated with subclinical Infections in bats, with Egyptian rousette bat (ERB, Rousettus aegyptiacus) being a natural MARV reservoir. To understand the nature of this resistance, we have analyzed how EBOV and MARV affect the transcriptomes of multiple ERB tissues. We have found that while the primary locus of Infection was the liver, gene expression was affected in multiple tissues, suggesting a systemic response. We have identified transcriptional changes that are indicative of inhibition of the complement system, induction of vasodilation, changes in coagulation, modulation of iron regulation, activation of a T cell response, and converting macrophages from the M1 to M2 state. We propose that these events are facets of a systemic anti-inflammatory state that enables effective control of the Infection in bats and suggest that dissecting this state can inform how to control a Filovirus Infection in humans.
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Ebola and Marburg Virus Infection in Bats Induces a Systemic Response
SSRN Electronic Journal, 2020Co-Authors: Anitha D Jayaprakash, Adam J Ronk, Abhishek N Prasad, Matthew F Covington, Kathryn R Stein, Toni M Schwarz, Saboor Hekmaty, Karla A Fenton, Thomas W Geisbert, Christopher F BaslerAbstract:The Filoviruses Ebola (EBOV) and Marburg (MARV) cause fatal disease in humans and nonhuman primates but cause subclinical Infections in bats. The Egyptian rousette bat (ERB, Rousettus aegyptiacus) is a natural MARV reservoir. To understand the nature of this resistance, we have analyzed how EBOV and MARV affect the transcriptomes of multiple ERB tissues. We found that while the primary locus of Infection was the liver, gene expression was affected in multiple tissues, suggesting a systemic response. We have identified transcriptional changes indicative of inhibition of the complement system, induction of vasodilation, changes in coagulation, modulation of iron regulation, activation of a T cell response, and converting macrophages from the M1 to M2 state. We propose that these events are facets of a systemic anti-inflammatory state that enables effective control of the Infection in bats and suggest that this state can inform how to control a Filovirus Infection in humans.
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Small animal models of Filovirus disease: recent advances and future directions
Expert opinion on drug discovery, 2018Co-Authors: Robert W. Cross, Karla A Fenton, Thomas W GeisbertAbstract:ABSTRACTIntroduction: Small animal models have played a critical role in understanding the pathogenesis and transmission of disease caused by Filoviruses. Notably, small animals have served to identify and validate many different approaches to countering Infection with these highly pathogenic viruses. Nonetheless, predictive efficacy between each model does not appear to be equivalent as higher order animals seem to be more prognostic and therefore successful in the evaluation of medical countermeasures (MCM).Areas covered: This review comprehensively details the available small animal models of Filovirus Infection and discusses the benefits and shortcomings of each model with respect to the development of MCM. An up-to-date evaluation of mouse, hamster, guinea pig, and ferret models is provided.Expert opinion: The recent development of the domestic ferret model for ebolavirus offers a small animal model that faithfully reproduces most features of human disease without the need for viral adaptation or an ...
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considerations in the use of nonhuman primate models of ebola virus and marburg virus Infection
The Journal of Infectious Diseases, 2015Co-Authors: Thomas W Geisbert, James E Strong, Heinz FeldmannAbstract:Abstract The Filoviruses, Ebola virus and Marburg virus, are zoonotic pathogens that cause severe hemorrhagic fever in humans and nonhuman primates (NHPs), with case-fatality rates ranging from 23% to 90%. The current outbreak of Ebola virus Infection in West Africa, with >26 000 cases, demonstrates the long-underestimated public health danger that Filoviruses pose as natural human pathogens. Currently, there are no vaccines or treatments licensed for human use. Licensure of any medical countermeasure may require demonstration of efficacy in the gold standard cynomolgus or rhesus macaque models of Filovirus Infection. Substantial progress has been made over the last decade in characterizing the Filovirus NHP models. However, there is considerable debate over a variety of experimental conditions, including differences among Filovirus isolates used, routes and doses of exposure, and euthanasia criteria, all of which may contribute to variability of results among different laboratories. As an example of the importance of understanding these differences, recent data with Ebola virus shows that an addition of a single uridine residue in the glycoprotein gene at the editing site attenuates the virus. Here, we draw on decades of experience working with Filovirus-infected NHPs to provide a perspective on the importance of various experimental conditions.