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Wellford SA, Moseman EA. Olfactory immunology: the missing piece in airway and CNS defence. Nat Rev Immunol 2024; 24:381-398. [PMID: 38097777 DOI: 10.1038/s41577-023-00972-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2023] [Indexed: 12/23/2023]
Abstract
The olfactory mucosa is a component of the nasal airway that mediates the sense of smell. Recent studies point to an important role for the olfactory mucosa as a barrier to both respiratory pathogens and to neuroinvasive pathogens that hijack the olfactory nerve and invade the CNS. In particular, the COVID-19 pandemic has demonstrated that the olfactory mucosa is an integral part of a heterogeneous nasal mucosal barrier critical to upper airway immunity. However, our insufficient knowledge of olfactory mucosal immunity hinders attempts to protect this tissue from infection and other diseases. This Review summarizes the state of olfactory immunology by highlighting the unique immunologically relevant anatomy of the olfactory mucosa, describing what is known of olfactory immune cells, and considering the impact of common infectious diseases and inflammatory disorders at this site. We will offer our perspective on the future of the field and the many unresolved questions pertaining to olfactory immunity.
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Affiliation(s)
- Sebastian A Wellford
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA
| | - E Ashley Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC, USA.
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2
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Gardner CL, Erwin-Cohen RA, Lewis BS, Bakken RR, Honnold SP, Glass PJ, Burke CW. Syrian Hamsters Model Does Not Reflect Human-like Disease after Aerosol Exposure to Encephalitic Alphaviruses. Methods Protoc 2024; 7:42. [PMID: 38804336 PMCID: PMC11130913 DOI: 10.3390/mps7030042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/06/2024] [Accepted: 05/13/2024] [Indexed: 05/29/2024] Open
Abstract
Venezuelan (VEE), eastern (EEE), and western (WEE) equine encephalitis viruses are encephalitic New World alphaviruses that cause periodic epizootic and epidemic outbreaks in horses and humans that may cause severe morbidity and mortality. Currently there are no FDA-licensed vaccines or effective antiviral therapies. Each year, there are a limited number of human cases of encephalitic alphaviruses; thus, licensure of a vaccine or therapeutic would require approval under the FDA animal rule. Approval under the FDA animal rule requires the disease observed in the animal model to recapitulate what is observed in humans. Currently, initial testing of vaccines and therapeutics is performed in the mouse model. Unfortunately, alphavirus disease manifestations in a mouse do not faithfully recapitulate human disease; the VEEV mouse model is lethal whereas in humans VEEV is rarely lethal. In an effort to identify a more appropriate small animal model, we evaluated hamsters in an aerosol exposure model of encephalitic alphavirus infection. The pathology, lethality, and viremia observed in the infected hamsters was inconsistent with what is observed in NHP models and humans. These data suggest that hamsters are not an appropriate model for encephalitic alphaviruses to test vaccines or potential antiviral therapies.
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Affiliation(s)
- Christina L. Gardner
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (C.L.G.); (R.A.E.-C.); (R.R.B.); (P.J.G.)
| | - Rebecca A. Erwin-Cohen
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (C.L.G.); (R.A.E.-C.); (R.R.B.); (P.J.G.)
| | - Bridget S. Lewis
- Pathology Division, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (B.S.L.); (S.P.H.)
| | - Russell R. Bakken
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (C.L.G.); (R.A.E.-C.); (R.R.B.); (P.J.G.)
| | - Shelley P. Honnold
- Pathology Division, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (B.S.L.); (S.P.H.)
| | - Pamela J. Glass
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (C.L.G.); (R.A.E.-C.); (R.R.B.); (P.J.G.)
- Risk Management Office, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA
| | - Crystal W. Burke
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Frederick, MD 21702, USA; (C.L.G.); (R.A.E.-C.); (R.R.B.); (P.J.G.)
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3
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Welch JL, Shrestha R, Hutchings H, Pal N, Levings R, Robbe-Austerman S, Palinski R, Shanmuganatham KK. Inactivation of highly transmissible livestock and avian viruses including influenza A and Newcastle disease virus for molecular diagnostics. Front Vet Sci 2024; 11:1304022. [PMID: 38515532 PMCID: PMC10955088 DOI: 10.3389/fvets.2024.1304022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/06/2024] [Indexed: 03/23/2024] Open
Abstract
There is a critical need for an inactivation method that completely inactivates pathogens at the time of sample collection while maintaining the nucleic acid quality required for diagnostic PCR testing. This inactivation method is required to alleviate concerns about transmission potential, minimize shipping complications and cost, and enable testing in lower containment laboratories, thereby enhancing disease diagnostics through improved turn-around time. This study evaluated a panel of 10 surrogate viruses that represent highly pathogenic animal diseases. These results showed that a commercial PrimeStore® molecular transport media (PSMTM) completely inactivated all viruses tested by >99.99%, as determined by infectivity and serial passage assays. However, the detection of viral nucleic acid by qRT-PCR was comparable in PSMTM and control-treated conditions. These results were consistent when viruses were evaluated in the presence of biological material such as sera and cloacal swabs to mimic diagnostic sample conditions for non-avian and avian viruses, respectively. The results of this study may be utilized by diagnostic testing laboratories for highly pathogenic agents affecting animal and human populations. These results may be used to revise guidance for select agent diagnostic testing and the shipment of infectious substances.
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Affiliation(s)
| | | | | | | | | | | | | | - Karthik K. Shanmuganatham
- National Veterinary Services Laboratories, Veterinary Services, Animal and Plant Health Inspection Service, United States Department of Agriculture, Ames, IA, United States
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Williamson LE, Bandyopadhyay A, Bailey K, Sirohi D, Klose T, Julander JG, Kuhn RJ, Crowe JE. Structural constraints link differences in neutralization potency of human anti-Eastern equine encephalitis virus monoclonal antibodies. Proc Natl Acad Sci U S A 2023; 120:e2213690120. [PMID: 36961925 PMCID: PMC10068833 DOI: 10.1073/pnas.2213690120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 02/10/2023] [Indexed: 03/26/2023] Open
Abstract
Selection and development of monoclonal antibody (mAb) therapeutics against pathogenic viruses depends on certain functional characteristics. Neutralization potency, or the half-maximal inhibitory concentration (IC50) values, is an important characteristic of candidate therapeutic antibodies. Structural insights into the bases of neutralization potency differences between antiviral neutralizing mAbs are lacking. In this report, we present cryo-electron microscopy (EM) reconstructions of three anti-Eastern equine encephalitis virus (EEEV) neutralizing human mAbs targeting overlapping epitopes on the E2 protein, with greater than 20-fold differences in their respective IC50 values. From our structural and biophysical analyses, we identify several constraints that contribute to the observed differences in the neutralization potencies. Cryo-EM reconstructions of EEEV in complex with these Fab fragments reveal structural constraints that dictate intravirion or intervirion cross-linking of glycoprotein spikes by their IgG counterparts as a mechanism of neutralization. Additionally, we describe critical features for the recognition of EEEV by these mAbs including the epitope-paratope interaction surface, occupancy, and kinetic differences in on-rate for binding to the E2 protein. Each constraint contributes to the extent of EEEV inhibition for blockade of virus entry, fusion, and/or egress. These findings provide structural and biophysical insights into the differences in mechanism and neutralization potencies of these antibodies, which help inform rational design principles for candidate vaccines and therapeutic antibodies for all icosahedral viruses.
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Affiliation(s)
- Lauren E. Williamson
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN37232
| | - Abhishek Bandyopadhyay
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Kevin Bailey
- Institute for Antiviral Research, Utah State University, Logan, UT84335
| | - Devika Sirohi
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - Thomas Klose
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | | | - Richard J. Kuhn
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN47907
| | - James E. Crowe
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN37232
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN37232
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5
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Reyna RA, Weaver SC. Sequelae and Animal Modeling of Encephalitic Alphavirus Infections. Viruses 2023; 15:v15020382. [PMID: 36851596 PMCID: PMC9959775 DOI: 10.3390/v15020382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
Eastern (EEEV), Venezuelan (VEEV), and western equine encephalitis viruses (WEEV) are members of the genus Alphavirus, family Togaviridae. Typically spread by mosquitoes, EEEV, VEEV, and WEEV induce febrile illness that may develop into more severe encephalitic disease, resulting in myriad severe neurologic sequelae for which there are no vaccines or therapeutics. Here, we summarize the clinical neurologic findings and sequelae induced by these three encephalitic viruses and describe the various animal models available to study them. We emphasize the crucial need for the development of advanced animal modeling combined with the use of telemetry, behavioral testing, and neuroimaging to facilitate a detailed mechanistic understanding of these encephalitic signs and sequelae. Through the use of these systems, much-needed therapeutics and vaccines can be developed.
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Affiliation(s)
- Rachel A. Reyna
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Scott C. Weaver
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
- Correspondence:
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Kehn-Hall K, Bradfute SB. Understanding host responses to equine encephalitis virus infection: implications for therapeutic development. Expert Rev Anti Infect Ther 2022; 20:1551-1566. [PMID: 36305549 DOI: 10.1080/14787210.2022.2141224] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Venezuelan, eastern, and western equine encephalitis viruses (VEEV, EEEV, and WEEV) are mosquito-borne New World alphaviruses that cause encephalitis in equids and humans. These viruses can cause severe disease and death, as well as long-term severe neurological symptoms in survivors. Despite the pathogenesis and weaponization of these viruses, there are no approved therapeutics for treating infection. AREAS COVERED In this review, we describe the molecular pathogenesis of these viruses, discuss host-pathogen interactions needed for viral replication, and highlight new avenues for drug development with a focus on host-targeted approaches. EXPERT OPINION Current approaches have yielded some promising therapeutics, but additional emphasis should be placed on advanced development of existing small molecules and pursuit of pan-encephalitic alphavirus drugs. More research should be conducted on EEEV and WEEV, given their high lethality rates.
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Affiliation(s)
- Kylene Kehn-Hall
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA.,Center for Emerging, Zoonotic, and Arthropod-borne Pathogens, Virginia Tech, Blacksburg, VA, USA
| | - Steven B Bradfute
- Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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Williams JA, Long SY, Zeng X, Kuehl K, Babka AM, Davis NM, Liu J, Trefry JC, Daye S, Facemire PR, Iversen PL, Bavari S, Pitt ML, Nasar F. Eastern equine encephalitis virus rapidly infects and disseminates in the brain and spinal cord of cynomolgus macaques following aerosol challenge. PLoS Negl Trop Dis 2022; 16:e0010081. [PMID: 35533188 PMCID: PMC9084534 DOI: 10.1371/journal.pntd.0010081] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 12/09/2021] [Indexed: 11/18/2022] Open
Abstract
Eastern equine encephalitis virus (EEEV) is mosquito-borne virus that produces fatal encephalitis in humans. We recently conducted a first of its kind study to investigate EEEV clinical disease course following aerosol challenge in a cynomolgus macaque model utilizing the state-of-the-art telemetry to measure critical physiological parameters. Here, we report the results of a comprehensive pathology study of NHP tissues collected at euthanasia to gain insights into EEEV pathogenesis. Viral RNA and proteins as well as microscopic lesions were absent in the visceral organs. In contrast, viral RNA and proteins were readily detected throughout the brain including autonomic nervous system (ANS) control centers and spinal cord. However, despite presence of viral RNA and proteins, majority of the brain and spinal cord tissues exhibited minimal or no microscopic lesions. The virus tropism was restricted primarily to neurons, and virus particles (~61–68 nm) were present within axons of neurons and throughout the extracellular spaces. However, active virus replication was absent or minimal in majority of the brain and was limited to regions proximal to the olfactory tract. These data suggest that EEEV initially replicates in/near the olfactory bulb following aerosol challenge and is rapidly transported to distal regions of the brain by exploiting the neuronal axonal transport system to facilitate neuron-to-neuron spread. Once within the brain, the virus gains access to the ANS control centers likely leading to disruption and/or dysregulation of critical physiological parameters to produce severe disease. Moreover, the absence of microscopic lesions strongly suggests that the underlying mechanism of EEEV pathogenesis is due to neuronal dysfunction rather than neuronal death. This study is the first comprehensive investigation into EEEV pathology in a NHP model and will provide significant insights into the evaluation of countermeasure. EEEV is an arbovirus endemic in parts of North America and is able to produce fatal encephalitis in humans and domesticated animals. Despite multiple human outbreaks during the last 80 years, there are still no therapeutic or vaccines to treat or prevent human disease. One critical obstacle in the development of effective countermeasure is the lack of insights into EEEV pathogenesis in a susceptible animal host. We recently conducted a study in cynomolgus macaques to investigate the disease course by measuring clinical parameters relevant to humans. Following infection, these parameters were rapidly and profoundly altered leading to severe disease. In this study, we examined the potential mechanisms that underlie pathogenesis to cause severe disease. The virus was present in many parts of the brain and spinal cord, however, minimal or no pathological lesions as well as active virus replication were observed. Additionally, neurons were the predominant target of EEEV infection and virus transport was facilitated via axonal transport system to spread neuron-to-neuron throughout the brain and spinal cord. These data show that EEEV likely hijacks essential transport system to rapidly spread in the brain and local/global neuronal dysfunction rather than neuronal death is the principal cause of severe disease.
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Affiliation(s)
- Janice A. Williams
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Simon Y. Long
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Xiankun Zeng
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Kathleen Kuehl
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - April M. Babka
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Neil M. Davis
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Jun Liu
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - John C. Trefry
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Sharon Daye
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Paul R. Facemire
- Pathology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Patrick L. Iversen
- Therapeutics Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Sina Bavari
- Office of the Commander, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
| | - Margaret L. Pitt
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
- Office of the Commander, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
- * E-mail: (MLP); , (FN)
| | - Farooq Nasar
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Frederick, Maryland, United States of America
- * E-mail: (MLP); , (FN)
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8
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Lucas CJ, Morrison TE. Animal models of alphavirus infection and human disease. Adv Virus Res 2022; 113:25-88. [DOI: 10.1016/bs.aivir.2022.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Williamson LE, Reeder KM, Bailey K, Tran MH, Roy V, Fouch ME, Kose N, Trivette A, Nargi RS, Winkler ES, Kim AS, Gainza C, Rodriguez J, Armstrong E, Sutton RE, Reidy J, Carnahan RH, McDonald WH, Schoeder CT, Klimstra WB, Davidson E, Doranz BJ, Alter G, Meiler J, Schey KL, Julander JG, Diamond MS, Crowe JE. Therapeutic alphavirus cross-reactive E1 human antibodies inhibit viral egress. Cell 2021; 184:4430-4446.e22. [PMID: 34416147 PMCID: PMC8418820 DOI: 10.1016/j.cell.2021.07.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 04/11/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022]
Abstract
Alphaviruses cause severe arthritogenic or encephalitic disease. The E1 structural glycoprotein is highly conserved in these viruses and mediates viral fusion with host cells. However, the role of antibody responses to the E1 protein in immunity is poorly understood. We isolated E1-specific human monoclonal antibodies (mAbs) with diverse patterns of recognition for alphaviruses (ranging from Eastern equine encephalitis virus [EEEV]-specific to alphavirus cross-reactive) from survivors of natural EEEV infection. Antibody binding patterns and epitope mapping experiments identified differences in E1 reactivity based on exposure of epitopes on the glycoprotein through pH-dependent mechanisms or presentation on the cell surface prior to virus egress. Therapeutic efficacy in vivo of these mAbs corresponded with potency of virus egress inhibition in vitro and did not require Fc-mediated effector functions for treatment against subcutaneous EEEV challenge. These studies reveal the molecular basis for broad and protective antibody responses to alphavirus E1 proteins.
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MESH Headings
- Alphavirus/immunology
- Animals
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/isolation & purification
- Antibodies, Neutralizing/immunology
- Antibodies, Viral/immunology
- Antigens, Viral/immunology
- Cell Line
- Chikungunya virus/immunology
- Cross Reactions/immunology
- Encephalitis Virus, Eastern Equine/immunology
- Encephalomyelitis, Equine/immunology
- Encephalomyelitis, Equine/virology
- Epitope Mapping
- Female
- Horses
- Humans
- Hydrogen-Ion Concentration
- Joints/pathology
- Male
- Mice, Inbred C57BL
- Models, Biological
- Protein Binding
- RNA, Viral/metabolism
- Receptors, Fc/metabolism
- Temperature
- Viral Proteins/immunology
- Virion/metabolism
- Virus Internalization
- Virus Release/physiology
- Mice
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Affiliation(s)
- Lauren E Williamson
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA; The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kristen M Reeder
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kevin Bailey
- Institute for Antiviral Research, Utah State University, Logan, UT 84335, USA
| | - Minh H Tran
- Chemical and Physical Biology Program, Vanderbilt University, Nashville, TN, USA; Center of Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Vicky Roy
- Ragon Institute of MGH, MIT, and Harvard University, Cambridge, MA 02139, USA
| | | | - Nurgun Kose
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Andrew Trivette
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel S Nargi
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Emma S Winkler
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Arthur S Kim
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA
| | - Christopher Gainza
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jessica Rodriguez
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Erica Armstrong
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Rachel E Sutton
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Joseph Reidy
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert H Carnahan
- The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - W Hayes McDonald
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Clara T Schoeder
- Center of Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - William B Klimstra
- The Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 165261, USA; Department of Immunology, University of Pittsburgh, Pittsburgh, PA 165261, USA
| | | | | | - Galit Alter
- Ragon Institute of MGH, MIT, and Harvard University, Cambridge, MA 02139, USA
| | - Jens Meiler
- Center of Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Chemistry, Vanderbilt University, Nashville, TN, USA; Institute for Drug Discovery, Leipzig University Medical School, Leipzig, Germany
| | - Kevin L Schey
- Department of Biochemistry and Mass Spectrometry Research Center, Vanderbilt University, Nashville, TN, USA
| | - Justin G Julander
- Institute for Antiviral Research, Utah State University, Logan, UT 84335, USA
| | - Michael S Diamond
- Department of Medicine, Washington University, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University, St. Louis, MO 63110, USA; Department of Molecular Microbiology, Washington University, St. Louis, MO 63110, USA
| | - James E Crowe
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, TN 37232, USA; Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; The Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Limbic Encephalitis Brain Damage Induced by Cocal Virus in Adult Mice Is Reduced by Environmental Enrichment: Neuropathological and Behavioral Studies. Viruses 2020; 13:v13010048. [PMID: 33396704 PMCID: PMC7824630 DOI: 10.3390/v13010048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/14/2020] [Indexed: 12/26/2022] Open
Abstract
We previously demonstrated, using the Piry virus model, that environmental enrichment promotes higher T-cell infiltration, fewer microglial changes, and faster central nervous system (CNS) virus clearance in adult mice. However, little is known about disease progression, behavioral changes, CNS cytokine concentration, and neuropathology in limbic encephalitis in experimental models. Using Cocal virus, we infected C57Bl6 adult mice and studied the neuroanatomical distribution of viral antigens in correlation with the microglial morphological response, measured the CNS cytokine concentration, and assessed behavioral changes. C57Bl6 adult mice were maintained in an impoverished environment (IE) or enriched environment (EE) for four months and then subjected to the open field test. Afterwards, an equal volume of normal or virus-infected brain homogenate was nasally instilled. The brains were processed to detect viral antigens and microglial morphological changes using selective immunolabeling. We demonstrated earlier significant weight loss and higher mortality in IE mice. Additionally, behavioral analysis revealed a significant influence of the environment on locomotor and exploratory activity that was associated with less neuroinvasion and a reduced microglial response. Thus, environmental enrichment was associated with a more effective immune response in a mouse model of limbic encephalitis, allowing faster viral clearance/decreased viral dissemination, reduced disease progression, and less CNS damage.
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11
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Miley KM, Downs J, Beeman SP, Unnasch TR. Impact of the Southern Oscillation Index, Temperature, and Precipitation on Eastern Equine Encephalitis Virus Activity in Florida. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1604-1613. [PMID: 32436566 DOI: 10.1093/jme/tjaa084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Indexed: 06/11/2023]
Abstract
Eastern equine encephalitis virus (EEEV), an Alphavirus from family Togaviridae, is a highly pathogenic arbovirus affecting the eastern United States, especially Florida. Effects of the Southern Oscillation Index (SOI), precipitation, and cooling degree days on EEEV horse case data in Florida from 2004 to 2018 were modeled using distributed lag nonlinear models (DLNMs). The analysis was conducted at statewide and regional scales. DLNMs were used to model potential delayed effects of the covariates on monthly counts of horse cases. Both models confirmed a seasonal trend in EEEV transmission and found that precipitation, cooling degree days, and the SOI were all predictors of monthly numbers of horse cases. EEEV activity in horses was associated with higher amounts of rainfall during the month of transmission at the statewide scale, as well as the prior 3 mo at the regional scale, fewer cooling degree days during the month of transmission and the preceding 3 mo and high SOI values during the month and the previous 2 mo, and SOI values in the prior 2 to 8 mo. Horse cases were lower during El Niño winters but higher during the following summer, while La Niña winters were associated with higher numbers of cases and fewer during the following summer. At the regional scale, extremely low levels of precipitation were associated with a suppression of EEEV cases for 3 mo. Given the periodicity and potential predictability of El Niño Southern Oscillation (ENSO) cycles, precipitation, and temperature, these results may provide a method for predicting EEEV risk potential in Florida.
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Affiliation(s)
- Kristi M Miley
- Global Health Infectious Disease Research, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, FL
| | - Joni Downs
- School of Geosciences, University of South Florida, 4202 E Fowler Ave, Tampa, FL
| | - Sean P Beeman
- Global Health Infectious Disease Research, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, FL
| | - Thomas R Unnasch
- Global Health Infectious Disease Research, University of South Florida, 3720 Spectrum Blvd, Suite 304, Tampa, FL
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12
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Abstract
Alphaviruses, members of the enveloped, positive-sense, single-stranded RNA Togaviridae family, represent a reemerging public health threat as mosquito vectors expand into new geographic territories. The Old World alphaviruses, which include chikungunya virus, Ross River virus, and Sindbis virus, tend to cause a clinical syndrome characterized by fever, rash, and arthritis, whereas the New World alphaviruses, which consist of Venezuelan equine encephalitis virus, eastern equine encephalitis virus, and western equine encephalitis virus, induce encephalomyelitis. Following recovery from the acute phase of infection, many patients are left with debilitating persistent joint and neurological complications that can last for years. Clues from human cases and studies using animal models strongly suggest that much of the disease and pathology induced by alphavirus infection, particularly atypical and chronic manifestations, is mediated by the immune system rather than directly by the virus. This review discusses the current understanding of the immunopathogenesis of the arthritogenic and neurotropic alphaviruses accumulated through both natural infection of humans and experimental infection of animals, particularly mice. As treatment following alphavirus infection is currently limited to supportive care, understanding the contribution of the immune system to the disease process is critical to developing safe and effective therapies.
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Affiliation(s)
- Victoria K Baxter
- Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Mark T Heise
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
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Salimi H, Cain MD, Jiang X, Roth RA, Beatty WL, Sun C, Klimstra WB, Hou J, Klein RS. Encephalitic Alphaviruses Exploit Caveola-Mediated Transcytosis at the Blood-Brain Barrier for Central Nervous System Entry. mBio 2020; 11:e02731-19. [PMID: 32047126 PMCID: PMC7018649 DOI: 10.1128/mbio.02731-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 12/23/2019] [Indexed: 12/14/2022] Open
Abstract
Venezuelan and western equine encephalitis viruses (VEEV and WEEV, respectively) invade the central nervous system (CNS) early during infection, via neuronal and hematogenous routes. While viral replication mediates host shutoff, including expression of type I interferons (IFN), few studies have addressed how alphaviruses gain access to the CNS during established infection or the mechanisms of viral crossing at the blood-brain barrier (BBB). Here, we show that hematogenous dissemination of VEEV and WEEV into the CNS occurs via caveolin-1 (Cav-1)-mediated transcytosis (Cav-MT) across an intact BBB, which is impeded by IFN and inhibitors of RhoA GTPase. Use of reporter and nonreplicative strains also demonstrates that IFN signaling mediates viral restriction within cells comprising the neurovascular unit (NVU), differentially rendering brain endothelial cells, pericytes, and astrocytes permissive to viral replication. Transmission and immunoelectron microscopy revealed early events in virus internalization and Cav-1 association within brain endothelial cells. Cav-1-deficient mice exhibit diminished CNS VEEV and WEEV titers during early infection, whereas viral burdens in peripheral tissues remained unchanged. Our findings show that alphaviruses exploit Cav-MT to enter the CNS and that IFN differentially restricts this process at the BBB.IMPORTANCE VEEV, WEEV, and eastern equine encephalitis virus (EEEV) are emerging infectious diseases in the Americas, and they have caused several major outbreaks in the human and horse population during the past few decades. Shortly after infection, these viruses can infect the CNS, resulting in severe long-term neurological deficits or death. Neuroinvasion has been associated with virus entry into the CNS directly from the bloodstream; however, the underlying molecular mechanisms have remained largely unknown. Here, we demonstrate that following peripheral infection alphavirus augments vesicular formation/trafficking at the BBB and utilizes Cav-MT to cross an intact BBB, a process regulated by activators of Rho GTPases within brain endothelium. In vivo examination of early viral entry in Cav-1-deficient mice revealed significantly lower viral burdens in the brain than in similarly infected wild-type animals. These studies identify a potentially targetable pathway to limit neuroinvasion by alphaviruses.
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Affiliation(s)
- Hamid Salimi
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Matthew D Cain
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Xiaoping Jiang
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Robyn A Roth
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Wandy L Beatty
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Chengqun Sun
- Department of Immunology and Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - William B Klimstra
- Department of Immunology and Center for Vaccine Research, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jianghui Hou
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Robyn S Klein
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri, USA
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Phelps AL, O’Brien LM, Eastaugh LS, Davies C, Lever MS, Ennis J, Zeitlin L, Nunez A, Ulaeto DO. Aerosol infection of Balb/c mice with eastern equine encephalitis virus; susceptibility and lethality. Virol J 2019; 16:2. [PMID: 30611287 PMCID: PMC6321726 DOI: 10.1186/s12985-018-1103-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/03/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Eastern equine encephalitis virus is an alphavirus that naturally cycles between mosquitoes and birds or rodents in Eastern States of the US. Equine infection occurs by being bitten by cross-feeding mosquitoes, with a case fatality rate of up to 75% in humans during epizootic outbreaks. There are no licensed medical countermeasures, and with an anticipated increase in mortality when exposed by the aerosol route based on anecdotal human data and experimental animal data, it is important to understand the pathogenesis of this disease in pursuit of treatment options. This report details the clinical and pathological findings of mice infected with EEEV by the aerosol route, and use as a model for EEEV infection in humans. METHODS Mice were exposed by the aerosol route to a dose range of EEEV to establish the median lethal dose. A pathogenesis study followed whereby mice were exposed to a defined dose of virus and sacrificed at time-points thereafter for histopathological analysis and virology. RESULTS Clinical signs of disease appeared within 2 days post challenge, culminating in severe clinical signs within 24 h, neuro-invasion and dose dependent lethality. EEEV was first detected in the lung 1 day post challenge, and by day 3 peak viral titres were observed in the brain, spleen and blood, corresponding with severe meningoencephalitis, indicative of encephalitic disease. Lethality follows severe neurological signs, and may be linked to a threshold level of virus replication in the brain. Effective medical countermeasures for EEEV may necessitate early inoculation to inhibit infection of the brain in zoonotic incidents, and be able to traverse the blood-brain barrier to sufficiently interrupt replication in the brain in cases of aerosol infection. CONCLUSIONS There is little human data on the hazard posed by aerosol infection with encephalitic alphaviruses, and use of EEEV as a bioweapon may be by the aerosol route. A well characterized model of aerosol exposure that recapitulates some of the most severe human clinical features is necessary to evaluate the efficacy of putative medical countermeasures, and to increase our understanding about how this route of infection induces such rapid neuro-invasion and resulting disease.
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Affiliation(s)
- Amanda L. Phelps
- CBR Division, Defence Science and Technology Laboratory (Dstl), Room 201, Building 7a,, Porton Down, Salisbury, Wiltshire SP4 0JQ UK
| | - Lyn M. O’Brien
- CBR Division, Defence Science and Technology Laboratory (Dstl), Room 201, Building 7a,, Porton Down, Salisbury, Wiltshire SP4 0JQ UK
| | - Lin S. Eastaugh
- CBR Division, Defence Science and Technology Laboratory (Dstl), Room 201, Building 7a,, Porton Down, Salisbury, Wiltshire SP4 0JQ UK
| | - Carwyn Davies
- CBR Division, Defence Science and Technology Laboratory (Dstl), Room 201, Building 7a,, Porton Down, Salisbury, Wiltshire SP4 0JQ UK
| | - Mark S. Lever
- CBR Division, Defence Science and Technology Laboratory (Dstl), Room 201, Building 7a,, Porton Down, Salisbury, Wiltshire SP4 0JQ UK
| | - Jane Ennis
- Mapp Biopharmaceutical Inc, 6160 Lusk Blvd. #C105, San Diego, CA 92121 USA
| | - Larry Zeitlin
- Mapp Biopharmaceutical Inc, 6160 Lusk Blvd. #C105, San Diego, CA 92121 USA
| | - Alejandro Nunez
- Pathology Unit, Animal and Plant Health Agency – Weybridge, Woodham Lane, New Haw, Addlestone, Surrey KT15 3NB UK
| | - David O. Ulaeto
- CBR Division, Defence Science and Technology Laboratory (Dstl), Room 201, Building 7a,, Porton Down, Salisbury, Wiltshire SP4 0JQ UK
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15
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Protective antibodies against Eastern equine encephalitis virus bind to epitopes in domains A and B of the E2 glycoprotein. Nat Microbiol 2018; 4:187-197. [PMID: 30455470 PMCID: PMC6294662 DOI: 10.1038/s41564-018-0286-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 10/10/2018] [Indexed: 12/21/2022]
Abstract
Eastern equine encephalitis virus (EEEV) is a mosquito-transmitted alphavirus with a high case mortality rate in humans. EEEV is a biodefense concern because of its potential for aerosol spread and the lack of existing countermeasures. In this study, we identified a panel of 18 neutralizing murine monoclonal antibodies (mAbs) against the EEEV E2 protein, several of which had “elite” activity with 50% and 99% inhibitory concentrations (EC50 and EC99) of less than 10 and 100 ng/ml, respectively. Alanine-scanning mutagenesis and neutralization escape mapping analysis revealed epitopes for these mAbs in domains A or B of the E2 glycoprotein. A majority of the neutralizing mAbs blocked at a post-attachment stage, with several inhibiting viral membrane fusion. Administration of one dose of anti-EEEV mAbs protected mice from lethal subcutaneous or aerosol challenge. These experiments define the mechanistic basis for neutralization by protective anti-EEEV mAbs and suggest a path forward for treatment and vaccine design.
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Rusnak JM, Dupuy LC, Niemuth NA, Glenn AM, Ward LA. Comparison of Aerosol- and Percutaneous-acquired Venezuelan Equine Encephalitis in Humans and Nonhuman Primates for Suitability in Predicting Clinical Efficacy under the Animal Rule. Comp Med 2018; 68:380-395. [PMID: 30282570 PMCID: PMC6200028 DOI: 10.30802/aalas-cm-18-000027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/19/2018] [Accepted: 06/06/2018] [Indexed: 12/25/2022]
Abstract
Licensure of medical countermeasure vaccines to protect against aerosolized Venezuelan equine encephalitis virus (VEEV) requires the use of the Animal Rule to assess vaccine efficacy, because human studies are not feasible or ethical. We therefore performed a retrospective study of VEE cases that occurred in at-risk laboratory workers and support personnel during the United States Biowarfare Program (1943-1969) to better define percutaneous- and aerosol-acquired VEE in humans and to compare these results with those described for the NHP model (in which high-dose aerosol VEEV challenge led to more severe encephalitis than parenteral challenge). Record review and analysis of 17 aerosol- and 23 percutaneous-acquired human cases of VEE included incubation period, symptoms, physical examination findings, and markers of infection. Human VEE disease by both exposure routes presented as acute febrile illness, typically with fever, chills, headache, back pain, malaise, myalgia, anorexia, and nausea. Aerosol exposure more commonly led to upper respiratory tract-associated findings of sore throat (59% compared with 26%), pharyngeal erythema (76% compared with 52%), neck pain (29% compared with 4%), and cervical lymphadenopathy (29% compared with 4%). Other disease manifestations, including encephalitis, were similar between the 2 exposure groups. The increase in upper respiratory tract findings in aerosol-acquired VEE in humans has not previously been reported but is supported by the mouse model, which showed nasal mucosal necrosis, necrotizing rhinitis, and an increase in upper respiratory tract viral burden associated with aerosol VEEV challenge. Fever, viremia, and lymphopenia were common markers of VEE disease in both humans and NHP, regardless of the exposure route. Taken collectively, our findings provide support for use of the nonlethal NHP model for advanced development of medical countermeasures against aerosol- or percutaneous-acquired VEE.
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Affiliation(s)
- Janice M Rusnak
- Joint Vaccine Acquisition Program, Medical Countermeasure Systems, and Battelle, Fort Detrick, Maryland, USA.
| | - Lesley C Dupuy
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA
| | | | - Andrew M Glenn
- Joint Vaccine Acquisition Program, Medical Countermeasure Systems, Fort Detrick, Maryland, USA
| | - Lucy A Ward
- Joint Vaccine Acquisition Program, Medical Countermeasure Systems, Fort Detrick, Maryland, USA
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Abstract
Alphaviruses, members of the positive-sense, single-stranded RNA virus family Togaviridae, represent a re-emerging public health concern worldwide as mosquito vectors expand into new geographic ranges. Members of the alphavirus genus tend to induce clinical disease characterized by rash, arthralgia, and arthritis (chikungunya virus, Ross River virus, and Semliki Forest virus) or encephalomyelitis (eastern equine encephalitis virus, western equine encephalitis virus, and Venezuelan equine encephalitis virus), though some patients who recover from the initial acute illness may develop long-term sequelae, regardless of the specific infecting virus. Studies examining the natural disease course in humans and experimental infection in cell culture and animal models reveal that host genetics play a major role in influencing susceptibility to infection and severity of clinical disease. Genome-wide genetic screens, including loss of function screens, microarrays, RNA-sequencing, and candidate gene studies, have further elucidated the role host genetics play in the response to virus infection, with the immune response being found in particular to majorly influence the outcome. This review describes the current knowledge of the mechanisms by which host genetic factors influence alphavirus pathogenesis and discusses emerging technologies that are poised to increase our understanding of the complex interplay between viral and host genetics on disease susceptibility and clinical outcome.
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18
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Porter AI, Erwin-Cohen RA, Twenhafel N, Chance T, Yee SB, Kern SJ, Norwood D, Hartman LJ, Parker MD, Glass PJ, DaSilva L. Characterization and pathogenesis of aerosolized eastern equine encephalitis in the common marmoset (Callithrix jacchus). Virol J 2017; 14:25. [PMID: 28173871 PMCID: PMC5297202 DOI: 10.1186/s12985-017-0687-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 01/18/2017] [Indexed: 02/02/2023] Open
Abstract
Background Licensed antiviral therapeutics and vaccines to protect against eastern equine encephalitis virus (EEEV) in humans currently do not exist. Animal models that faithfully recapitulate the clinical characteristics of human EEEV encephalitic disease, including fever, drowsiness, anorexia, and neurological signs such as seizures, are needed to satisfy requirements of the Food and Drug Administration (FDA) for clinical product licensing under the Animal Rule. Methods In an effort to meet this requirement, we estimated the median lethal dose and described the pathogenesis of aerosolized EEEV in the common marmoset (Callithrix jacchus). Five marmosets were exposed to aerosolized EEEV FL93-939 in doses ranging from 2.4 × 101 PFU to 7.95 × 105 PFU. Results The median lethal dose was estimated to be 2.05 × 102 PFU. Lethality was observed as early as day 4 post-exposure in the highest-dosed marmoset but animals at lower inhaled doses had a protracted disease course where humane study endpoint was not met until as late as day 19 post-exposure. Clinical signs were observed as early as 3 to 4 days post-exposure, including fever, ruffled fur, decreased grooming, and leukocytosis. Clinical signs increased in severity as disease progressed to include decreased body weight, subdued behavior, tremors, and lack of balance. Fever was observed as early as day 2–3 post-exposure in the highest dose groups and hypothermia was observed in several cases as animals became moribund. Infectious virus was found in several key tissues, including brain, liver, kidney, and several lymph nodes. Clinical hematology results included early neutrophilia, lymphopenia, and thrombocytopenia. Key pathological changes included meningoencephalitis and retinitis. Immunohistochemical staining for viral antigen was positive in the brain, retina, and lymph nodes. More intense and widespread IHC labeling occurred with increased aerosol dose. Conclusion We have estimated the medial lethal dose of aerosolized EEEV and described the pathology of clinical disease in the marmoset model. The results demonstrate that the marmoset is an animal model suitable for emulation of human EEEV disease in the development of medical countermeasures. Electronic supplementary material The online version of this article (doi:10.1186/s12985-017-0687-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Aimee I Porter
- United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Virology Division, Frederick, MD, 21702, USA
| | - Rebecca A Erwin-Cohen
- United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Virology Division, Frederick, MD, 21702, USA.
| | | | | | - Steven B Yee
- Center for Aerobiological Sciences, Frederick, MD, 21702, USA
| | - Steven J Kern
- Research Support Division, Frederick, MD, 21702, USA
| | - David Norwood
- Diagnostic Systems Division, Frederick, MD, 21702, USA
| | | | - Michael D Parker
- United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Virology Division, Frederick, MD, 21702, USA
| | - Pamela J Glass
- United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Virology Division, Frederick, MD, 21702, USA
| | - Luis DaSilva
- Center for Aerobiological Sciences, Frederick, MD, 21702, USA
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Salimi H, Cain MD, Klein RS. Encephalitic Arboviruses: Emergence, Clinical Presentation, and Neuropathogenesis. Neurotherapeutics 2016; 13:514-34. [PMID: 27220616 PMCID: PMC4965410 DOI: 10.1007/s13311-016-0443-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Arboviruses are arthropod-borne viruses that exhibit worldwide distribution, contributing to systemic and neurologic infections in a variety of geographical locations. Arboviruses are transmitted to vertebral hosts during blood feedings by mosquitoes, ticks, biting flies, mites, and nits. While the majority of arboviral infections do not lead to neuroinvasive forms of disease, they are among the most severe infectious risks to the health of the human central nervous system. The neurologic diseases caused by arboviruses include meningitis, encephalitis, myelitis, encephalomyelitis, neuritis, and myositis in which virus- and immune-mediated injury may lead to severe, persisting neurologic deficits or death. Here we will review the major families of emerging arboviruses that cause neurologic infections, their neuropathogenesis and host neuroimmunologic responses, and current strategies for treatment and prevention of neurologic infections they cause.
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Affiliation(s)
- Hamid Salimi
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Matthew D Cain
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Robyn S Klein
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA.
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Entry Sites of Venezuelan and Western Equine Encephalitis Viruses in the Mouse Central Nervous System following Peripheral Infection. J Virol 2016; 90:5785-96. [PMID: 27053560 DOI: 10.1128/jvi.03219-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 04/03/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Venezuelan and western equine encephalitis viruses (VEEV and WEEV; Alphavirus; Togaviridae) are mosquito-borne pathogens causing central nervous system (CNS) disease in humans and equids. Adult CD-1 mice also develop CNS disease after infection with VEEV and WEEV. Adult CD-1 mice infected by the intranasal (i.n.) route, showed that VEEV and WEEV enter the brain through olfactory sensory neurons (OSNs). In this study, we injected the mouse footpad with recombinant WEEV (McMillan) or VEEV (subtype IC strain 3908) expressing firefly luciferase (fLUC) to simulate mosquito infection and examined alphavirus entry in the CNS. Luciferase expression served as a marker of infection detected as bioluminescence (BLM) by in vivo and ex vivo imaging. BLM imaging detected WEEV and VEEV at 12 h postinoculation (hpi) at the injection site (footpad) and as early as 72 hpi in the brain. BLM from WEEV.McM-fLUC and VEEV.3908-fLUC injections was initially detected in the brain's circumventricular organs (CVOs). No BLM activity was detected in the olfactory neuroepithelium or OSNs. Mice were also injected in the footpad with WEEV.McM expressing DsRed (Discosoma sp.) and imaged by confocal fluorescence microscopy. DsRed imaging supported our BLM findings by detecting WEEV in the CVOs prior to spreading along the neuronal axis to other brain regions. Taken together, these findings support our hypothesis that peripherally injected alphaviruses enter the CNS by hematogenous seeding of the CVOs followed by centripetal spread along the neuronal axis. IMPORTANCE VEEV and WEEV are mosquito-borne viruses causing sporadic epidemics in the Americas. Both viruses are associated with CNS disease in horses, humans, and mouse infection models. In this study, we injected VEEV or WEEV, engineered to express bioluminescent or fluorescent reporters (fLUC and DsRed, respectively), into the footpads of outbred CD-1 mice to simulate transmission by a mosquito. Reporter expression serves as detectable bioluminescent and fluorescent markers of VEEV and WEEV replication and infection. Bioluminescence imaging, histological examination, and confocal fluorescence microscopy were used to identify early entry sites of these alphaviruses in the CNS. We observed that specific areas of the brain (circumventricular organs [CVOs]) consistently showed the earliest signs of infection with VEEV and WEEV. Histological examination supported VEEV and WEEV entering the brain of mice at specific sites where the blood-brain barrier is naturally absent.
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Eastern equine encephalitis virus in mice I: clinical course and outcome are dependent on route of exposure. Virol J 2015; 12:152. [PMID: 26420265 PMCID: PMC4588493 DOI: 10.1186/s12985-015-0386-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 09/15/2015] [Indexed: 12/05/2022] Open
Abstract
Background Eastern equine encephalitis virus (EEEV), an arbovirus, is an important human and veterinary pathogen belonging to one of seven antigenic complexes in the genus Alphavirus, family Togaviridae. EEEV is considered the most deadly of the mosquito-borne alphaviruses due to the high case fatality rate associated with clinical infections, reaching up to 75 % in humans and 90 % in horses. In patients that survive acute infection, neurologic sequelae are often devastating. Although natural infections are acquired by mosquito bite, EEEV is also highly infectious by aerosol. This fact, along with the relative ease of production and stability of this virus, has led it to being identified as a potential agent of bioterrorism. Methods To characterize the clinical course and outcome of EEEV strain FL93-939 infection, we compared clinical parameters, cytokine expression, viremia, and viral titers in numerous tissues of mice exposed by various routes. Twelve-week-old female BALB/c mice were infected by the intranasal, aerosol, or subcutaneous route. Mice were monitored for clinical signs of disease and euthanized at specified time points (6 hpi through 8 dpi). Blood and tissues were harvested for cytokine analysis and/or viral titer determination. Results Although all groups of animals exhibited similar clinical signs after inoculation, the onset and severity differed. The majority of those animals exposed by the aerosol route developed severe clinical signs by 4 dpi. Significant differences were also observed in the viral titers of target tissues, with virus being detected in the brain at 6 hpi in the aerosol study. Conclusion The clinical course and outcome of EEEV infection in mice is dependent on route of exposure. Aerosol exposure to EEEV results in acute onset of clinical signs, rapid neuroinvasion, and 100 % mortality. Electronic supplementary material The online version of this article (doi:10.1186/s12985-015-0386-1) contains supplementary material, which is available to authorized users.
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