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Hensley LE, Mulangu S, Asiedu C, Johnson J, Honko AN, Stanley D, Fabozzi G, Nichol ST, Ksiazek TG, Rollin PE, Wahl-Jensen V, Bailey M, Jahrling PB, Roederer M, Koup RA, Sullivan NJ. Demonstration of cross-protective vaccine immunity against an emerging pathogenic Ebolavirus Species. PLoS Pathog 2010; 6:e1000904. [PMID: 20502688 PMCID: PMC2873919 DOI: 10.1371/journal.ppat.1000904] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Accepted: 04/09/2010] [Indexed: 11/19/2022] Open
Abstract
A major challenge in developing vaccines for emerging pathogens is their continued evolution and ability to escape human immunity. Therefore, an important goal of vaccine research is to advance vaccine candidates with sufficient breadth to respond to new outbreaks of previously undetected viruses. Ebolavirus (EBOV) vaccines have demonstrated protection against EBOV infection in nonhuman primates (NHP) and show promise in human clinical trials but immune protection occurs only with vaccines whose antigens are matched to the infectious challenge species. A 2007 hemorrhagic fever outbreak in Uganda demonstrated the existence of a new EBOV species, Bundibugyo (BEBOV), that differed from viruses covered by current vaccine candidates by up to 43% in genome sequence. To address the question of whether cross-protective immunity can be generated against this novel species, cynomolgus macaques were immunized with DNA/rAd5 vaccines expressing ZEBOV and SEBOV glycoprotein (GP) prior to lethal challenge with BEBOV. Vaccinated subjects developed robust, antigen-specific humoral and cellular immune responses against the GP from ZEBOV as well as cellular immunity against BEBOV GP, and immunized macaques were uniformly protected against lethal challenge with BEBOV. This report provides the first demonstration of vaccine-induced protective immunity against challenge with a heterologous EBOV species, and shows that Ebola vaccines capable of eliciting potent cellular immunity may provide the best strategy for eliciting cross-protection against newly emerging heterologous EBOV species. Ebola virus causes death, fear, and economic disruption during outbreaks. It is a concern worldwide as a natural pathogen and a bioterrorism agent, and has caused death to residents and tourists of Africa where the virus circulates. A vaccine strategy to protect against all circulating Ebola viruses is complicated by the fact that there are five different virus species, and individual vaccines provide protection only against those included in the vaccine. Making broad vaccines that contain multiple components is complicated, expensive, and poses challenges for regulatory approval. Therefore, in the present work, we examined whether a prime-boost immunization strategy with a vaccine targeted to one Ebola virus species could cross protect against a different species. We found that genetic immunization with vectors expressing the Ebola virus glycoprotein from Zaire blocked infection with a newly emerged virus species, Bundibugyo EBOV, not represented in the vaccine. Protection occurred in the absence of antibodies against the second species and was mediated instead by cellular immune responses. Therefore, single-component vaccines may be improved to protect against multiple Ebola viruses if they are designed to generate this type of immunity.
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Affiliation(s)
- Lisa E. Hensley
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Sabue Mulangu
- Biodefense Research Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Clement Asiedu
- Biodefense Research Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Joshua Johnson
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Anna N. Honko
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Daphne Stanley
- Biodefense Research Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Giulia Fabozzi
- Biodefense Research Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Stuart T. Nichol
- Special Pathogens Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Thomas G. Ksiazek
- Special Pathogens Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Pierre E. Rollin
- Special Pathogens Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Victoria Wahl-Jensen
- Virology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Michael Bailey
- Biodefense Research Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Peter B. Jahrling
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mario Roederer
- Immunology Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Richard A. Koup
- Immunology Laboratory, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nancy J. Sullivan
- Biodefense Research Section, Vaccine Research Center, National Institute of Allergy and Infectious Disease, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Smith DR, McCarthy S, Chrovian A, Olinger G, Stossel A, Geisbert TW, Hensley LE, Connor JH. Inhibition of heat-shock protein 90 reduces Ebola virus replication. Antiviral Res 2010; 87:187-94. [PMID: 20452380 DOI: 10.1016/j.antiviral.2010.04.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2010] [Revised: 04/22/2010] [Accepted: 04/30/2010] [Indexed: 12/24/2022]
Abstract
Ebola virus (EBOV), a negative-sense RNA virus in the family Filoviridae, is known to cause severe hemorrhagic fever in humans and other primates. Infection with EBOV causes a high mortality rate and currently there is no FDA-licensed vaccine or therapeutic treatment available. Recently, heat-shock protein 90 (Hsp90), a molecular chaperone, was shown to be an important host factor for the replication of several negative-strand viruses. We tested the effect of several different Hsp90 inhibitors including geldanamycin, radicicol, and 17-allylamino-17-demethoxygeldanamycin (17-AAG; a geldanamycin analog) on the replication of Zaire EBOV. Our results showed that inhibition of Hsp90 significantly reduced the replication of EBOV. Classic Hsp90 inhibitors reduced viral replication with an effective concentration at 50% (EC(50)) in the high nanomolar to low micromolar range, while drugs from a new class of Hsp90 inhibitors showed markedly more potent inhibition. These compounds blocked EBOV replication with an EC(50) in the low nanomolar range and showed significant potency in blocking replication in primary human monocytes. These results validated that Hsp90 is an important host factor for the replication of filoviruses and suggest that Hsp90 inhibitors may be therapeutically effective in treating EBOV infection.
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Affiliation(s)
- Darci R Smith
- U.S. Army Medical Research Institute of Infectious Diseases, Virology Division, Fort Detrick, MD, United States
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353
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Basler CF, Amarasinghe GK. Evasion of interferon responses by Ebola and Marburg viruses. J Interferon Cytokine Res 2010; 29:511-20. [PMID: 19694547 DOI: 10.1089/jir.2009.0076] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The filoviruses, Ebola virus (EBOV) and Marburg virus (MARV), cause frequently lethal viral hemorrhagic fever. These infections induce potent cytokine production, yet these host responses fail to prevent systemic virus replication. Consistent with this, filoviruses have been found to encode proteins VP35 and VP24 that block host interferon (IFN)-alpha/beta production and inhibit signaling downstream of the IFN-alpha/beta and the IFN-gamma receptors, respectively. VP35, which is a component of the viral nucleocapsid complex and plays an essential role in viral RNA synthesis, acts as a pseudosubstrate for the cellular kinases IKK-epsilon and TBK-1, which phosphorylate and activate interferon regulatory factor 3 (IRF-3) and interferon regulatory factor 7 (IRF-7). VP35 also promotes SUMOylation of IRF-7, repressing IFN gene transcription. In addition, VP35 is a dsRNA-binding protein, and mutations that disrupt dsRNA binding impair VP35 IFN-antagonist activity while leaving its RNA replication functions intact. The phenotypes of recombinant EBOV bearing mutant VP35s unable to inhibit IFN-alpha/beta demonstrate that VP35 IFN-antagonist activity is critical for full virulence of these lethal pathogens. The structure of the VP35 dsRNA-binding domain, which has recently become available, is expected to provide insight into how VP35 IFN-antagonist and dsRNA-binding functions are related. The EBOV VP24 protein inhibits IFN signaling through an interaction with select host cell karyopherin-alpha proteins, preventing the nuclear import of otherwise activated STAT1. It remains to be determined to what extent VP24 may also modulate the nuclear import of other host cell factors and to what extent this may influence the outcome of infection. Notably, the Marburg virus VP24 protein does not detectably block STAT1 nuclear import, and, unlike EBOV, MARV infection inhibits STAT1 and STAT2 phosphorylation. Thus, despite their similarities, there are fundamental differences by which these deadly viruses counteract the IFN system. It will be of interest to determine how these differences influence pathogenesis.
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Affiliation(s)
- Christopher F Basler
- Department of Microbiology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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354
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Pratt WD, Wang D, Nichols DK, Luo M, Woraratanadharm J, Dye JM, Holman DH, Dong JY. Protection of nonhuman primates against two species of Ebola virus infection with a single complex adenovirus vector. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:572-81. [PMID: 20181765 PMCID: PMC2849326 DOI: 10.1128/cvi.00467-09] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 01/18/2010] [Accepted: 02/10/2010] [Indexed: 11/20/2022]
Abstract
Ebola viruses are highly pathogenic viruses that cause outbreaks of hemorrhagic fever in humans and other primates. To meet the need for a vaccine against the several types of Ebola viruses that cause human diseases, we developed a multivalent vaccine candidate (EBO7) that expresses the glycoproteins of Zaire ebolavirus (ZEBOV) and Sudan ebolavirus (SEBOV) in a single complex adenovirus-based vector (CAdVax). We evaluated our vaccine in nonhuman primates against the parenteral and aerosol routes of lethal challenge. EBO7 vaccine provided protection against both Ebola viruses by either route of infection. Significantly, protection against SEBOV given as an aerosol challenge, which has not previously been shown, could be achieved with a boosting vaccination. These results demonstrate the feasibility of creating a robust, multivalent Ebola virus vaccine that would be effective in the event of a natural virus outbreak or biological threat.
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Affiliation(s)
- William D Pratt
- U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, MD 21702-5011, USA.
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355
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Flatz L, Rieger T, Merkler D, Bergthaler A, Regen T, Schedensack M, Bestmann L, Verschoor A, Kreutzfeldt M, Brück W, Hanisch UK, Günther S, Pinschewer DD. T cell-dependence of Lassa fever pathogenesis. PLoS Pathog 2010; 6:e1000836. [PMID: 20360949 PMCID: PMC2847900 DOI: 10.1371/journal.ppat.1000836] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 02/26/2010] [Indexed: 12/22/2022] Open
Abstract
Lassa virus (LASV), the causative agent of Lassa fever (LF), is endemic in West Africa, accounting for substantial morbidity and mortality. In spite of ongoing research efforts, LF pathogenesis and mechanisms of LASV immune control remain poorly understood. While normal laboratory mice are resistant to LASV, we report that mice expressing humanized instead of murine MHC class I (MHC-I) failed to control LASV infection and develop severe LF. Infection of MHC-I knockout mice confirmed a key role for MHC-I-restricted T cell responses in controlling LASV. Intriguingly we found that T cell depletion in LASV-infected HHD mice prevented disease, irrespective of high-level viremia. Widespread activation of monocyte/macrophage lineage cells, manifest through inducible NO synthase expression, and elevated IL-12p40 serum levels indicated a systemic inflammatory condition. The absence of extensive monocyte/macrophage activation in T cell-depleted mice suggested that T cell responses contribute to deleterious innate inflammatory reactions and LF pathogenesis. Our observations in mice indicate a dual role for T cells, not only protecting from LASV, but also enhancing LF pathogenesis. The possibility of T cell-driven enhancement and immunopathogenesis should be given consideration in future LF vaccine development. Lassa virus (LASV) is the causative agent of Lassa fever (LF), accounting for substantial morbidity and mortality in West Africa. Yet the mechanisms leading to disease remain poorly understood. Here we propose a concept whereby the body's immune defense either defeats LASV rapidly or, if unsuccessful, becomes an essential facilitator of disease. This latter paradoxical postulate stems from observations in genetically engineered (HHD) mice, which we found to be susceptible to LF. HHD mice differ from resistant wild type mice in that they have a humanized repertoire of T cells, a main component of the mammalian immune system. Counterintuitively, we could protect HHD mice against LF by experimentally removing their T cells. We further found that LF correlated with widespread activation of macrophages, which again depended on T cells. Similar to T cells, macrophages are important players in our body's defense system, but their inflammatory products are also candidate mediators of LF. Taken together, these findings suggest that LF may represent an inappropriate host response to infection. Specifically, our study demonstrates a two-faced role of T cell responses against LASV. Such detrimental aspects of immune defense need to be given consideration in future LF vaccine development, to avoid enhancement of disease in vaccinated individuals.
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Affiliation(s)
- Lukas Flatz
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- Institute of Experimental Immunology, Department of Pathology, University Hospital of Zurich, Zurich, Switzerland
| | - Toni Rieger
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Doron Merkler
- Department of Neuropathology, Georg-August-University, Göttingen, Germany
| | - Andreas Bergthaler
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- Institute of Experimental Immunology, Department of Pathology, University Hospital of Zurich, Zurich, Switzerland
| | - Tommy Regen
- Department of Neuropathology, Georg-August-University, Göttingen, Germany
| | | | - Lukas Bestmann
- Institute of Clinical Chemistry, University Hospital of Zurich, Zurich, Switzerland
- Unilabs Dr. Weber, St. Gallen, Switzerland
| | - Admar Verschoor
- Institute of Experimental Immunology, Department of Pathology, University Hospital of Zurich, Zurich, Switzerland
| | - Mario Kreutzfeldt
- Department of Neuropathology, Georg-August-University, Göttingen, Germany
| | - Wolfgang Brück
- Department of Neuropathology, Georg-August-University, Göttingen, Germany
| | | | - Stephan Günther
- Department of Virology, Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany
| | - Daniel D. Pinschewer
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
- Institute of Experimental Immunology, Department of Pathology, University Hospital of Zurich, Zurich, Switzerland
- W.H.O. Collaborating Center for Neonatal Vaccinology, University of Geneva, Geneva, Switzerland
- * E-mail:
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356
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Abstract
PURPOSE OF REVIEW To consider the relevance to severe human lung infections of recently discovered virulence mechanisms of Staphylococcus aureus and Francisella tularensis. RECENT FINDINGS S. aureus has long been considered an opportunistic pathogen. However, due to the emergence of community-acquired methicillin-resistant S. aureus (CA-MRSA) strains that can readily infect and kill normal hosts, S. aureus must now be considered a potentially virulent pathogen. The evolution of S. aureus from an organism associated with asymptomatic nasopharyngeal colonization to one associated with community-acquired lethal infections may reflect horizontal acquisition of bacterial genes that enable efficient spread, aggressive host invasion, and effective immune evasion. Alleviating the burden of staphylococcal disease will require better understanding of host susceptibility and of staphylococcal virulence and antibiotic resistance. In contrast to the rapidly evolving staphylococcal virulence strategy, recent genomic analysis of F. tularensis has revealed a small set of bacterial genes associated with the marked virulence of its North American subspecies. This suggests that a relatively stable strategy of immune evasion underlies this pathogen's ability to establish serious life-threatening lung infections from a very small inoculum. SUMMARY Understanding bacterial pathogenesis will require additional research into both host susceptibility factors and bacterial virulence mechanisms, including horizontal gene transfer. Refinements in the molecular detection of bacteria in the clinical setting, as well as whole genome analysis of both pathogens and patients, are expected to aid in the understanding of bacterial-induced lung injury.
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357
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358
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Rodas JD, Cairo C, Djavani M, Zapata JC, Ruckwardt T, Bryant J, Pauza CD, Lukashevich IS, Salvato MS. Circulating natural killer and gammadelta T cells decrease soon after infection of rhesus macaques with lymphocytic choriomeningitis virus. Mem Inst Oswaldo Cruz 2010; 104:583-91. [PMID: 19722081 DOI: 10.1590/s0074-02762009000400009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Accepted: 05/15/2009] [Indexed: 11/22/2022] Open
Abstract
Rhesus macaques infected with the WE strain of lymphocytic choriomeningitis virus (LCMV-WE) serve as a model for human infection with Lassa fever virus. To identify the earliest events of acute infection, rhesus macaques were monitored immediately after lethal infection for changes in peripheral blood mononuclear cells (PBMCs). Changes in CD3, CD4, CD8 and CD20 subsets did not vary outside the normal fluctuations of these blood cell populations; however, natural killer (NK) and gammadelta T cells increased slightly on day 1 and then decreased significantly after two days. The NK subsets responsible for the decrease were primarily CD3-CD8+ or CD3-CD16+ and not the NKT (primarily CD3+CD56+) subset. Macaques infected with a non-virulent arenavirus, LCMV-Armstrong, showed a similar drop in circulating NK and gammadelta T cells, indicating that this is not a pathogenic event. V(3)9 T cells, representing the majority of circulating gammadelta T cells in rhesus macaques, displayed significant apoptosis when incubated with LCMV in cell culture; however, the low amount of cell death for virus-co-cultured NK cells was insufficient to account for the observed disappearance of this subset. Our observations in primates are similar to those seen in LCMV-infected mice, where decreased circulating NK cells were attributed to margination and cell death. Thus, the disappearance of these cells during acute hemorrhagic fever in rhesus macaques may be a cytokine-induced lymphopenia common to many virus infections.
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Affiliation(s)
- Juan D Rodas
- Grupo de Investigaciones en Ciencias Veterinarias Centauro, Facultad de Ciencias Agrarias, Universidad de Antioquia, Medellín, Colombia
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359
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Cárdenas WB. Evasion of the interferon-mediated antiviral response by filoviruses. Viruses 2010; 2:262-282. [PMID: 21994610 PMCID: PMC3185555 DOI: 10.3390/v2010262] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 01/11/2010] [Accepted: 01/19/2010] [Indexed: 01/09/2023] Open
Abstract
The members of the filoviruses are recognized as some of the most lethal viruses affecting human and non-human primates. The only two genera of the Filoviridae family, Marburg virus (MARV) and Ebola virus (EBOV), comprise the main etiologic agents of severe hemorrhagic fever outbreaks in central Africa, with case fatality rates ranging from 25 to 90%. Fatal outcomes have been associated with a late and dysregulated immune response to infection, very likely due to the virus targeting key host immune cells, such as macrophages and dendritic cells (DCs) that are necessary to mediate effective innate and adaptive immune responses. Despite major progress in the development of vaccine candidates for filovirus infections, a licensed vaccine or therapy for human use is still not available. During the last ten years, important progress has been made in understanding the molecular mechanisms of filovirus pathogenesis. Several lines of evidence implicate the impairment of the host interferon (IFN) antiviral innate immune response by MARV or EBOV as an important determinant of virulence. In vitro and in vivo experimental infections with recombinant Zaire Ebola virus (ZEBOV), the best characterized filovirus, demonstrated that the viral protein VP35 plays a key role in inhibiting the production of IFN-α/β. Further, the action of VP35 is synergized by the inhibition of cellular responses to IFN-α/β by the minor matrix viral protein VP24. The dual action of these viral proteins may contribute to an efficient initial virus replication and dissemination in the host. Noticeably, the analogous function of these viral proteins in MARV has not been reported. Because the IFN response is a major component of the innate immune response to virus infection, this chapter reviews recent findings on the molecular mechanisms of IFN-mediated antiviral evasion by filovirus infection.
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Affiliation(s)
- Washington B Cárdenas
- Laboratorio de Biomedicina, FIMCM, Escuela Superior Politécnica del Litoral (ESPOL), Campus Gustavo Galindo, Km 30.5 via Perimetral, Apartado 09-01-5863, Guayaquil, Ecuador
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360
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Bradfute SB, Swanson PE, Smith MA, Watanabe E, McDunn JE, Hotchkiss RS, Bavari S. Mechanisms and consequences of ebolavirus-induced lymphocyte apoptosis. THE JOURNAL OF IMMUNOLOGY 2010; 184:327-35. [PMID: 20028660 DOI: 10.4049/jimmunol.0901231] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ebolavirus (EBOV) is a member of the filovirus family and causes severe hemorrhagic fever, resulting in death in up to 90% of infected humans. EBOV infection induces massive bystander lymphocyte apoptosis; however, neither the cellular apoptotic pathway(s) nor the systemic implications of lymphocyte apoptosis in EBOV infection are known. In this study, we show data suggesting that EBOV-induced lymphocyte apoptosis in vivo occurs via both the death receptor (extrinsic) and mitochondrial (intrinsic) pathways, as both Fas-associated death domain dominant negative transgenic mice and mice overexpressing bcl-2 were resistant to EBOV-induced lymphocyte apoptosis. Surprisingly, inhibiting lymphocyte apoptosis during EBOV infection did not result in improved animal survival. Furthermore, we show for the first time that hepatocyte apoptosis likely occurs in EBOV infection, and that mice lacking the proapoptotic genes Bim and Bid had reduced hepatocyte apoptosis and liver enzyme levels postinfection. Collectively, these data suggest that EBOV induces multiple proapoptotic stimuli and that blocking lymphocyte apoptosis is not sufficient to improve survival in EBOV infection. These data suggest that hepatocyte apoptosis may play a role in the pathogenesis of EBOV infection, whereas lymphocyte apoptosis appears to be nonessential for EBOV disease progression.
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Affiliation(s)
- Steven B Bradfute
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD 21702, USA
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361
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Peyrefitte CN, Perret M, Garcia S, Rodrigues R, Bagnaud A, Lacote S, Crance JM, Vernet G, Garin D, Bouloy M, Paranhos-Baccalà G. Differential activation profiles of Crimean-Congo hemorrhagic fever virus- and Dugbe virus-infected antigen-presenting cells. J Gen Virol 2010; 91:189-98. [PMID: 19812268 DOI: 10.1099/vir.0.015701-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is a highly pathogenic, tick-borne member of the family Bunyaviridae and the genus Nairovirus. To better elucidate the pathogenesis of CCHFV, we analysed the host innate immune response induced in antigen-presenting cells (APCs) infected in vitro by CCHFV. Monocyte-derived dendritic cells (DCs) and macrophages (MPs) were both shown to be permissive for CCHFV and to replicate the virus, as monitored by genomic and antigenomic strand quantification. Virus replication was, however, controlled, corroborating an efficient alpha interferon-induced response. The upregulation of CD-83 and CD-86 indicated that CCHFV induced a partial maturation of DCs, which were also shown to activate the secretion of interleukin (IL)-6 and IL-8, but no tumour necrosis factor alpha (TNF-alpha). On the other hand, in MPs, CCHFV infection elicited a high IL-6 and TNF-alpha response and a moderate chemokine response. Nevertheless, when we compared these APC responses with those seen after infection with Dugbe virus (DUGV), a mildly pathogenic virus genetically close to CCHFV, we found that, in spite of some similarities, DUGV induced a higher cytokine/chemokine response in MPs. These results suggest that CCHFV is able to inhibit the activation of inflammatory mediators selectively in infection in vitro and that these differences could be relevant in pathogenesis.
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Affiliation(s)
- Christophe N Peyrefitte
- Emerging Pathogens Laboratory, Fondation Mérieux, IFR128 BioSciences Lyon-Gerland, Lyon, France
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362
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Jin H, Yan Z, Prabhakar BS, Feng Z, Ma Y, Verpooten D, Ganesh B, He B. The VP35 protein of Ebola virus impairs dendritic cell maturation induced by virus and lipopolysaccharide. J Gen Virol 2009; 91:352-61. [PMID: 19828757 DOI: 10.1099/vir.0.017343-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Ebola virus causes rapidly progressive haemorrhagic fever, which is associated with severe immuosuppression. In infected dendritic cells (DCs), Ebola virus replicates efficiently and inhibits DC maturation without inducing cytokine expression, leading to impaired T-cell proliferation. However, the underlying mechanism remains unclear. In this study, we report that Ebola virus VP35 impairs the maturation of mouse DCs. When expressed in mouse immature DCs, Ebola virus VP35 prevents virus-stimulated expression of CD40, CD80, CD86 and major histocompatibility complex class II. Further, it suppresses the induction of cytokines such as interleukin (IL)-6, IL-12, tumour necrosis factor alpha and alpha/beta interferon (IFN-alpha/beta). Notably, Ebola VP35 attenuates the ability of DCs to stimulate the activation of CD4(+) T cells. Addition of type I IFN to mouse DCs only partially reverses the inhibitory effects of VP35. Moreover, VP35 perturbs mouse DC functions induced by lipopolysaccharide, an agonist of Toll-like receptor 4. Deletion of the amino terminus abolishes its activity, whereas a mutation in the RNA binding motif has no effect. Our work highlights a critical role of VP35 in viral interference in DC function with resultant deficiency in T-cell function, which may contribute to the profound virulence of Ebola virus infection.
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Affiliation(s)
- Huali Jin
- Department of Microbiology and Immunology, College of Medicine, University of Illinois, Chicago, IL 60612, USA
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363
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Martinez O, Johnson J, Manicassamy B, Rong L, Olinger GG, Hensley LE, Basler CF. Zaire Ebola virus entry into human dendritic cells is insensitive to cathepsin L inhibition. Cell Microbiol 2009; 12:148-57. [PMID: 19775255 DOI: 10.1111/j.1462-5822.2009.01385.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cathepsins B and L contribute to Ebola virus (EBOV) entry into Vero cells and mouse embryonic fibroblasts. However, the role of cathepsins in EBOV-infection of human dendritic cells (DCs), important targets of infection in vivo, remains undefined. Here, EBOV-like particles containing a beta-lactamase-VP40 fusion reporter and Ebola virus were used to demonstrate the cathepsin dependence of EBOV entry into human monocyte-derived DCs. However, while DC infection is blocked by cathepsin B inhibitor, it is insensitive to cathepsin L inhibitor. Furthermore, DCs pre-treated for 48 h with TNFalpha were generally less susceptible to entry and infection by EBOV. This decrease in infection was associated with a decrease in cathepsin B activity. Thus, cathepsin L plays a minimal, if any, role in EBOV infection in human DCs. The inflammatory cytokine TNFalpha modulates cathepsin B activity and affects EBOV entry into and infection of human DCs.
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Affiliation(s)
- Osvaldo Martinez
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA
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364
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Bente D, Gren J, Strong JE, Feldmann H. Disease modeling for Ebola and Marburg viruses. Dis Model Mech 2009; 2:12-7. [PMID: 19132113 DOI: 10.1242/dmm.000471] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The filoviruses Ebola and Marburg are zoonotic agents that are classified as both biosafety level 4 and category A list pathogens. These viruses are pathogenic in humans and cause isolated infections or epidemics of viral hemorrhagic fever, mainly in Central Africa. Their natural reservoir has not been definitely identified, but certain species of African bat have been associated with Ebola and Marburg infections. Currently, there are no licensed options available for either treatment or prophylaxis. Different animal models have been developed for filoviruses including mouse, guinea pig and nonhuman primates. The 'gold standard' animal models for pathogenesis, treatment and vaccine studies are rhesus and cynomolgus macaques. This article provides a brief overview of the clinical picture and the pathology/pathogenesis of human filovirus infections. The current animal model options are discussed and compared with regard to their value in different applications. In general, the small animal models, in particular the mouse, are the most feasible for high biocontainment facilities and they offer the most options for research owing to the greater availability of immunologic and genetic tools. However, their mimicry of the human diseases as well as their predictive value for therapeutic efficacy in primates is limited, thereby making them, at best, valuable initial screening tools for pathophysiology, treatment and vaccine studies.
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Affiliation(s)
- Dennis Bente
- Laboratory for Zoonotic Diseases and Special Pathogens, National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Manitoba, Canada
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365
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Steele KE, Anderson AO, Mohamadzadeh M. Fibroblastic reticular cells and their role in viral hemorrhagic fevers. Expert Rev Anti Infect Ther 2009; 7:423-35. [PMID: 19400762 DOI: 10.1586/eri.09.13] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Viral hemorrhagic fevers (VHFs) caused by Ebola, Marburg and Lassa viruses often manifest as multiple organ dysfunction and hemorrhagic shock with high mortality. These viruses target numerous cell types, including monocytes and dendritic cells, which are primary early targets that mediate critical pathogenetic processes. This review focuses on fibroblastic reticular cells (FRCs), another prevalent infected cell type that is known as a key regulator of circulatory and immune functions. Viral infection of FRCs could have debilitating effects in secondary lymphoid organs and various other tissues. FRCs may also contribute to the spread of these deadly viruses throughout the body. Here, we review the salient features of these VHFs and the biology of FRCs, emphasizing the potential role of these cells in VHFs and the rapid deterioration of immune and hemovascular sytems that are characteristic of such acute infections.
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Affiliation(s)
- Keith E Steele
- Division of Pathology, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA.
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366
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Tigabu B, Juelich T, Bertrand J, Holbrook MR. Clinical evaluation of highly pathogenic tick-borne flavivirus infection in the mouse model. J Med Virol 2009; 81:1261-9. [DOI: 10.1002/jmv.21524] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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367
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Chang TH, Kubota T, Matsuoka M, Jones S, Bradfute SB, Bray M, Ozato K. Ebola Zaire virus blocks type I interferon production by exploiting the host SUMO modification machinery. PLoS Pathog 2009; 5:e1000493. [PMID: 19557165 PMCID: PMC2696038 DOI: 10.1371/journal.ppat.1000493] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 05/28/2009] [Indexed: 12/12/2022] Open
Abstract
Ebola Zaire virus is highly pathogenic for humans, with case fatality rates approaching 90% in large outbreaks in Africa. The virus replicates in macrophages and dendritic cells (DCs), suppressing production of type I interferons (IFNs) while inducing the release of large quantities of proinflammatory cytokines. Although the viral VP35 protein has been shown to inhibit IFN responses, the mechanism by which it blocks IFN production has not been fully elucidated. We expressed VP35 from a mouse-adapted variant of Ebola Zaire virus in murine DCs by retroviral gene transfer, and tested for IFN transcription upon Newcastle Disease virus (NDV) infection and toll-like receptor signaling. We found that VP35 inhibited IFN transcription in DCs following these stimuli by disabling the activity of IRF7, a transcription factor required for IFN transcription. By yeast two-hybrid screens and coimmunoprecipitation assays, we found that VP35 interacted with IRF7, Ubc9 and PIAS1. The latter two are the host SUMO E2 enzyme and E3 ligase, respectively. VP35, while not itself a SUMO ligase, increased PIAS1-mediated SUMOylation of IRF7, and repressed Ifn transcription. In contrast, VP35 did not interfere with the activation of NF-κB, which is required for induction of many proinflammatory cytokines. Our findings indicate that Ebola Zaire virus exploits the cellular SUMOylation machinery for its advantage and help to explain how the virus overcomes host innate defenses, causing rapidly overwhelming infection to produce a syndrome resembling fulminant septic shock. Ebola Zaire virus causes severe hemorrhagic fever in humans that is fatal in almost 90% of cases. The rapid spread of the virus to macrophages and dendritic cells results in the release of high levels of inflammatory cytokines, causing shock and bleeding. The ability of Ebola virus to overwhelm host defenses is believed to result from its suppression of the type I interferon (IFN) response. The Ebola viral protein VP35 is known to block IFN responses, but the precise mechanisms have not been identified. We expressed VP35 in mouse dendritic cells and found that the cells failed to develop a normal IFN response when infected with Newcastle Disease virus. By a yeast two-hybrid system and other biochemical experiments, we showed that the blockade resulted from the conjugation of a Small Ubiquitin-like Modifier (SUMO) protein to IRF-7, the principal cellular factor required for IFN gene expression. However, the cells were still able to activate NF-κB, a transcription factor responsible for the release of proinflammatory cytokines. Our findings provide a first example where a virus hijacks the host SUMO system to undermine innate immunity, and help to explain how Ebola virus spreads rapidly in lymphoid tissues to cause a lethal inflammatory syndrome.
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Affiliation(s)
- Tsung-Hsien Chang
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Toru Kubota
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mayumi Matsuoka
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Steven Jones
- Population and Public Health Branch, National Microbiology Laboratory, Canadian Science Centre for Human and Animal Health, Winnipeg, Manitoba, Canada
| | - Steven B. Bradfute
- United States Army Medical Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Mike Bray
- Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Maryland, United States of America
| | - Keiko Ozato
- Program in Genomics of Differentiation, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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368
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Abstract
Bluetongue virus (BTV) is the etiological agent of bluetongue, a hemorrhagic disease of ruminants (particularly sheep), which causes important economic losses around the world. BTV is transmitted primarily via the bites of infected midges, which inject the virus into the ruminant's skin during blood feeding. The virus initially replicates in the draining lymph node and then disseminates to secondary organs where it induces edema, hemorrhages, and necrosis. In this study, we show that ovine conventional dendritic cells (cDCs) are the primary targets of BTV that contribute to the primary dissemination of BTV from the skin to draining lymph nodes. Lymph cDCs support BTV RNA and protein synthesis, as well as the production of infectious virus belonging to several different BTV serotypes, regardless of their level of attenuation. Afferent lymph cell subsets, other than cDCs, showed only marginal levels of BTV protein expression. BTV infection provoked a massive recruitment of cDCs to the sheep skin and afferent lymph, providing cellular targets for infection. Although BTV productively infects cDCs, no negative impact on their physiology was detected. Indeed, BTV infection and protein expression in cDCs enhanced their survival rate. Several serotypes of BTV stimulated the surface expression of the CD80 and CD86 costimulatory molecules on cDCs as well as the mRNA synthesis of cytokines involved in inflammation and immunity, i.e., interleukin-12 (IL-12), IL-1beta, and IL-6. BTV-infected cDCs stimulated antigen-specific CD4 and CD8 proliferation as well as gamma interferon production. BTV initially targets cDCs while preserving their functional properties, reflecting the optimal adaptation of the virus to its host cells for its first spread.
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369
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Spurgers KB, Silvestri LS, Warfield KL, Bavari S. Toward RNA interference-based therapy for filovirus infections. Drug Dev Res 2009. [DOI: 10.1002/ddr.20302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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370
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Vy D, Pandya Y, Lavoie TB, Jubin RG. Performance Evaluation of the New VeriKine™ Cynomolgus/Rhesus IFN- α Serum ELISA Kit. Biotechniques 2009. [DOI: 10.2144/000113157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Diane Vy
- PBL InterferonSource, 131 Ethel Road West, Suite 6, Piscataway, NJ, 08854, USA
| | - Yognandan Pandya
- PBL InterferonSource, 131 Ethel Road West, Suite 6, Piscataway, NJ, 08854, USA
| | - Thomas B. Lavoie
- PBL InterferonSource, 131 Ethel Road West, Suite 6, Piscataway, NJ, 08854, USA
| | - Ronald G. Jubin
- PBL InterferonSource, 131 Ethel Road West, Suite 6, Piscataway, NJ, 08854, USA
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371
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Abstract
The viral protein VP35 of ebolavirus (EBOV) is implicated to have diverse roles in the viral life cycle. We employed a yeast two-hybrid screen to search for VP35 binding partners and identified the cytoplasmic dynein light chain (DLC8) as a protein that interacts with VP35. Mapping analysis unraveled a consensus motif, SQTQT, within VP35 through which VP35 binds to DLC8. The disruption of DLC8 binding does not affect the ability of VP35 to inhibit type I IFN production. Given that VP35 from various EBOV species interacts with DLC8, this interaction may have a role in regulating the EBOV life cycle.
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372
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Sullivan NJ, Martin JE, Graham BS, Nabel GJ. Correlates of protective immunity for Ebola vaccines: implications for regulatory approval by the animal rule. Nat Rev Microbiol 2009; 7:393-400. [PMID: 19369954 PMCID: PMC7097244 DOI: 10.1038/nrmicro2129] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Ebola is a rare but deadly disease caused by a filovirus for which no treatment or vaccine is available. Vaccine development for such diseases is hampered by the inability to test vaccines in volunteers or a target population. The Food and Drug Administration (FDA) has instituted the 'animal rule' to allow approval of vaccines and drugs that cannot be tested in humans based on immune correlates in animal models. In the case of Ebola, the relevant animal models are non-human primates and mice. For Ebola, immune correlates consist of immunoglobulin G responses, although other factors, such as T cells, are also likely to be important in a successful immune response. Vaccine candidates for Ebola vaccine include the glycoprotein and nucleocapsid proteins. Initial testing of Ebola vaccines has shown a protective effect in non-human primates and positive antibody titres in humans.
For diseases that are both rare and lethal, it is difficult to test vaccines. Sullivan and colleagues describe the use of immune correlates and the animal rule for the licensing of Ebola vaccines. Ebola virus infection is a highly lethal disease for which there are no effective therapeutic or preventive treatments. Several vaccines have provided immune protection in laboratory animals, but because outbreaks occur unpredictably and sporadically, vaccine efficacy cannot be proven in human trials, which is required for traditional regulatory approval. The Food and Drug Administration has introduced the 'animal rule', to allow laboratory animal data to be used to show efficacy when human trials are not logistically feasible. In this Review, we describe immune correlates of vaccine protection against Ebola virus in animals. This research provides a basis for bridging the gap from basic research to human vaccine responses in support of the licensing of vaccines through the animal rule.
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373
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Abstract
The lack of a mouse model has hampered an understanding of the pathogenesis and immunity of Marburg hemorrhagic fever (MHF), the disease caused by marburgvirus (MARV), and has created a bottleneck in the development of antiviral therapeutics. Primary isolates of the filoviruses, i.e., ebolavirus (EBOV) and MARV, are not lethal to immunocompetent adult mice. Previously, pathological, virologic, and immunologic evaluation of a mouse-adapted EBOV, developed by sequential passages in suckling mice, identified many similarities between this model and EBOV infections in nonhuman primates. We recently demonstrated that serially passaging virus recovered from the liver homogenates of MARV-infected immunodeficient (SCID) mice was highly successful in reducing the time to death in these mice from 50 to 70 days to 7 to 10 days after challenge with the isolate MARV-Ci67, -Musoke, or -Ravn. In this study, we extended our findings to show that further sequential passages of MARV-Ravn in immunocompetent mice caused the MARV to kill BALB/c mice. Serial sampling studies to characterize the pathology of mouse-adapted MARV-Ravn revealed that this model is similar to the guinea pig and nonhuman primate MHF models. Infection of BALB/c mice with mouse-adapted MARV-Ravn caused uncontrolled viremia and high viral titers in the liver, spleen, lymph node, and other organs; profound lymphopenia; destruction of lymphocytes within the spleen and lymph nodes; and marked liver damage and thrombocytopenia. Sequencing the mouse-adapted MARV-Ravn strain revealed differences in 16 predicted amino acids from the progenitor virus, although the exact changes required for adaptation are unclear at this time. This mouse-adapted MARV strain can now be used to develop and evaluate novel vaccines and therapeutics and may also help to provide a better understanding of the virulence factors associated with MARV.
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374
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Steele KE, Anderson AO, Mohamadzadeh M. Fibroblastic reticular cell infection by hemorrhagic fever viruses. Immunotherapy 2009; 1:187-97. [DOI: 10.2217/1750743x.1.2.187] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Viral hemorrhagic fevers (VHFs) often cause high mortality with high infectivity, multiorgan failure, shock and hemorrhagic diathesis. Fibroblastic reticular cells (FRCs) within secondary lymphoid organs provide a supporting scaffold to T-lymphocyte areas. These cells regulate the movement of various immune cells and soluble molecules that promote T-lymphocyte homeostasis. We previously reported Ebola virus infection of FRCs, but ascribed little significance to this finding. Here, we studied infection of FRCs by Ebola, Marburg and Lassa viruses. We demonstrate that FRCs, or the extracellular ‘conduit’ of the fibroblastic reticulum of nonhuman primates, are targets of Ebola, Marburg and Lassa viruses. Furthermore, we observed that FRC damage correlates temporally and spatially with lymphocyte damage and that FRCs serve as nidi of fibrin deposition. In addition, we show that nonhuman primate FRCs express p75 NGF receptor and tissue transglutaminase. Our data suggest that viral infection of FRCs may be crucial to the immunological dysfunction and coagulopathy characteristic of VHFs. We further propose that p75 NGF receptor and tissue transglutaminase may be involved in FRC-associated dysfunction during the course of infection.
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Affiliation(s)
- Keith E Steele
- Division of Pathology, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA
| | - Arthur O Anderson
- Division of Pathology, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Frederick, MD 21702, USA
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375
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Chemical modifications of antisense morpholino oligomers enhance their efficacy against Ebola virus infection. Antimicrob Agents Chemother 2009; 53:2089-99. [PMID: 19223614 DOI: 10.1128/aac.00936-08] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphorodiamidate morpholino oligomers (PMOs) are uncharged nucleic acid-like molecules designed to inactivate the expression of specific genes via the antisense-based steric hindrance of mRNA translation. PMOs have been successful at knocking out viral gene expression and replication in the case of acute viral infections in animal models and have been well tolerated in human clinical trials. We propose that antisense PMOs represent a promising class of therapeutic agents that may be useful for combating filoviral infections. We have previously shown that mice treated with a PMO whose sequence is complementary to a region spanning the start codon of VP24 mRNA were protected against lethal Ebola virus challenge. In the present study, we report on the abilities of two additional VP24-specific PMOs to reduce the cell-free translation of a VP24 reporter, to inhibit the in vitro replication of Ebola virus, and to protect mice against lethal challenge when the PMOs are delivered prior to infection. Additionally, structure-activity relationship evaluations were conducted to assess the enhancement of antiviral efficacy associated with PMO chemical modifications that included conjugation with peptides of various lengths and compositions, positioning of conjugated peptides to either the 5' or the 3' terminus, and the conferring of charge modifications by the addition of piperazine moieties. Conjugation with arginine-rich peptides greatly enhanced the antiviral efficacy of VP24-specific PMOs in infected cells and mice during lethal Ebola virus challenge.
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376
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Geisbert TW, Daddario-Dicaprio KM, Geisbert JB, Reed DS, Feldmann F, Grolla A, Ströher U, Fritz EA, Hensley LE, Jones SM, Feldmann H. Vesicular stomatitis virus-based vaccines protect nonhuman primates against aerosol challenge with Ebola and Marburg viruses. Vaccine 2008; 26:6894-900. [PMID: 18930776 PMCID: PMC3398796 DOI: 10.1016/j.vaccine.2008.09.082] [Citation(s) in RCA: 151] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Revised: 09/18/2008] [Accepted: 09/24/2008] [Indexed: 10/21/2022]
Abstract
Considerable progress has been made over the last decade in developing candidate preventive vaccines that can protect nonhuman primates against Ebola and Marburg viruses. A vaccine based on recombinant vesicular stomatitis virus (VSV) seems to be particularly robust as it can also confer protection when administered as a postexposure treatment. While filoviruses are not thought to be transmitted by aerosol in nature the inhalation route is among the most likely portals of entry in the setting of a bioterrorist event. At present, all candidate filoviral vaccines have been evaluated against parenteral challenges but none have been tested against an aerosol exposure. Here, we evaluated our recombinant VSV-based Zaire ebolavirus (ZEBOV) and Marburg virus (MARV) vaccines against aerosol challenge in cynomolgus macaques. All monkeys vaccinated with a VSV vector expressing the glycoprotein of ZEBOV were completely protected against an aerosol exposure of ZEBOV. Likewise, all monkeys vaccinated with a VSV vector expressing the glycoprotein of MARV were completely protected against an aerosol exposure of MARV. All control animals challenged by the aerosol route with either ZEBOV or MARV succumbed. Interestingly, disease in control animals appeared to progress slower than previously seen in macaques exposed to comparable doses by intramuscular injection.
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Affiliation(s)
- Thomas W Geisbert
- National Emerging Infectious Diseases Laboratories Institute, Boston University School of Medicine, Boston, MA, USA.
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377
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Geisbert TW, Daddario-Dicaprio KM, Lewis MG, Geisbert JB, Grolla A, Leung A, Paragas J, Matthias L, Smith MA, Jones SM, Hensley LE, Feldmann H, Jahrling PB. Vesicular stomatitis virus-based ebola vaccine is well-tolerated and protects immunocompromised nonhuman primates. PLoS Pathog 2008; 4:e1000225. [PMID: 19043556 PMCID: PMC2582959 DOI: 10.1371/journal.ppat.1000225] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Accepted: 10/31/2008] [Indexed: 12/21/2022] Open
Abstract
Ebola virus (EBOV) is a significant human pathogen that presents a public health concern as an emerging/re-emerging virus and as a potential biological weapon. Substantial progress has been made over the last decade in developing candidate preventive vaccines that can protect nonhuman primates against EBOV. Among these prospects, a vaccine based on recombinant vesicular stomatitis virus (VSV) is particularly robust, as it can also confer protection when administered as a postexposure treatment. A concern that has been raised regarding the replication-competent VSV vectors that express EBOV glycoproteins is how these vectors would be tolerated by individuals with altered or compromised immune systems such as patients infected with HIV. This is especially important as all EBOV outbreaks to date have occurred in areas of Central and Western Africa with high HIV incidence rates in the population. In order to address this concern, we evaluated the safety of the recombinant VSV vector expressing the Zaire ebolavirus glycoprotein (VSVΔG/ZEBOVGP) in six rhesus macaques infected with simian-human immunodeficiency virus (SHIV). All six animals showed no evidence of illness associated with the VSVΔG/ZEBOVGP vaccine, suggesting that this vaccine may be safe in immunocompromised populations. While one goal of the study was to evaluate the safety of the candidate vaccine platform, it was also of interest to determine if altered immune status would affect vaccine efficacy. The vaccine protected 4 of 6 SHIV-infected macaques from death following ZEBOV challenge. Evaluation of CD4+ T cells in all animals showed that the animals that succumbed to lethal ZEBOV challenge had the lowest CD4+ counts, suggesting that CD4+ T cells may play a role in mediating protection against ZEBOV. Ebola virus is among the most lethal microbes known to man, with case fatality rates often exceeding 80%. Since its discovery in 1976, outbreaks have been sporadic and geographically restricted, primarily to areas of Central Africa. However, concern about the natural or unnatural introduction of Ebola outside of the endemic areas has dramatically increased both research interest and public awareness. A number of candidate vaccines have been developed to combat Ebola virus, and these vaccines have shown varying degrees of success in nonhuman primate models. Safety is a significant concern for any vaccine and in particular for vaccines that replicate in the host. Here, we evaluated the safety of our replication-competent vesicular stomatitus virus (VSV)-based Ebola vaccine in SHIV-infected rhesus monkeys. We found that the vaccine caused no evidence of overt illness in any of these immunocompromised animals. We also demonstrated that this vaccine partially protected the SHIV-infected monkeys against a lethal Ebola challenge and that there appears to be an association with levels of CD4+ lymphocytes and survival. Our study suggests that the VSV-based Ebola vaccine will be safe in immunocompromised populations and supports further study and development of this promising vaccine platform for its use in humans.
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Affiliation(s)
- Thomas W Geisbert
- National Emerging Infectious Diseases Laboratories Institute, Boston, Massachusetts, USA.
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378
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Francica JR, Matukonis MK, Bates P. Requirements for cell rounding and surface protein down-regulation by Ebola virus glycoprotein. Virology 2008; 383:237-47. [PMID: 19013626 DOI: 10.1016/j.virol.2008.10.029] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 10/06/2008] [Accepted: 10/10/2008] [Indexed: 01/08/2023]
Abstract
Ebola virus causes an acute hemorrhagic fever that is associated with high morbidity and mortality. The viral glycoprotein is thought to contribute to pathogenesis, though precise mechanisms are unknown. Cellular pathogenesis can be modeled in vitro by expression of the Ebola viral glycoprotein (GP) in cells, which causes dramatic morphological changes, including cell rounding and surface protein down-regulation. These effects are known to be dependent on the presence of a highly glycosylated region of the glycoprotein, the mucin domain. Here we show that the mucin domain from the highly pathogenic Zaire subtype of Ebola virus is sufficient to cause characteristic cytopathology when expressed in the context of a foreign glycoprotein. Similarly to full length Ebola GP, expression of the mucin domain causes rounding, detachment from the extracellular matrix, and the down-regulation of cell surface levels of beta1 integrin and major histocompatibility complex class 1. These effects were not seen when the mucin domain was expressed in the context of a glycophosphatidylinositol-anchored isoform of the foreign glycoprotein. In contrast to earlier analysis of full length Ebola glycoproteins, chimeras carrying the mucin domains from the Zaire and Reston strains appear to cause similar levels of down-modulation and cell detachment. Cytopathology associated with Ebola glycoprotein expression does not occur when GP expression is restricted to the endoplasmic reticulum. In contrast to a previously published report, our results demonstrate that GP-induced surface protein down-regulation is not mediated through a dynamin-dependent pathway. Overall, these results support a model in which the mucin domain of Ebola GP acts at the cell surface to induce protein down modulation and cytopathic effects.
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Affiliation(s)
- Joseph R Francica
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, 19104-6076, USA
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379
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Detection of viral RNA from paraffin-embedded tissues after prolonged formalin fixation. J Clin Virol 2008; 44:39-42. [PMID: 18977691 DOI: 10.1016/j.jcv.2008.09.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 09/05/2008] [Accepted: 09/05/2008] [Indexed: 11/20/2022]
Abstract
BACKGROUND Isolating amplifiable RNA from formalin-fixed, paraffin-embedded (FFPE) tissues is more difficult than isolating DNA because of RNases, chemical modification of the RNA, and cross-linking of nucleic acids and proteins. Tissues containing infectious disease agents that require biosafety level (BSL)-3 and -4 necessitate fixation times of 21 and 30 days, respectively. OBJECTIVE To improve procedures for extracting RNA from these FFPE tissues and detect the RNA with the more sensitive TaqManbased reverse transcriptase (RT)-PCR. STUDY DESIGN Through a single modification of a commercially available kit, we were able to extract amplifiable RNA and detect West Nile virus (WNV), Marburg virus (MARV), and Ebola virus (EBOV)-infected tissues using TaqMan assays. RESULTS Formalin fixation results in an approximately 2log(10) reduction in detection limit when compared to fresh tissues. Increasing proteinase K digestion (24h) improved extraction of amplifiable RNA from FFPE tissues. The TaqMan results were comparable to more traditional detection results such as virus isolation. CONCLUSION This improved extraction procedure for obtaining RNA combined with the TaqMan RT-PCR assays permit retrospective and prospective studies on FFPE tissues infected with BSL-3 and -4 pathogens.
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380
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A key role for Toll-like receptor-3 in disrupting the hemostasis balance on endothelial cells. Blood 2008; 113:714-22. [PMID: 18971420 DOI: 10.1182/blood-2008-02-137901] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Various virus infections cause dysfunctional hemostasis and in some instances lead to the development of viral hemorrhagic fever syndrome. How do diverse viruses induce the expression of tissue factor on vascular cells? We hypothesize that a direct stimulation of pattern recognition receptors (PRR) by viral nucleic acids may be the key. Double-stranded RNA (dsRNA) is produced by many viruses and is recognized by various PRR, including Toll-like receptor-3 (TLR3). We have investigated whether poly I:C, a model for viral dsRNA, can influence cellular hemostasis. Poly I:C could up-regulate tissue factor and down-regulate thrombomodulin expression on endothelial cells but not on monocytes. The response to poly I:C was diminished upon small interfering RNA (siRNA)-mediated inhibition of TLR3, but not other PRR. In vivo, application of poly I:C induced similar changes in the aortic endothelium of mice as determined by enface microscopy. D-dimer, a circulating marker for enhanced coagulation and fibrinolysis, and tissue fibrin deposition was elevated. All the hemostasis-related responses to poly I:C, but not cytokine secretion, were blunted in TLR3(-/-) mice. Hence, the activation of TLR3 can induce the procoagulant state in the endothelium, and this could be relevant for understanding the mechanisms of viral stimulation of hemostasis.
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381
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Fritz EA, Geisbert JB, Geisbert TW, Hensley LE, Reed DS. Cellular Immune Response to Marburg Virus Infection in Cynomolgus Macaques. Viral Immunol 2008; 21:355-63. [DOI: 10.1089/vim.2008.0023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Elizabeth A. Fritz
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland
| | | | | | - Lisa E. Hensley
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland
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382
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Yang C, Ye L, Compans RW. Protection against filovirus infection: virus-like particle vaccines. Expert Rev Vaccines 2008; 7:333-44. [PMID: 18393603 DOI: 10.1586/14760584.7.3.333] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Significant progress has been made in vaccine development against infection by Ebola and Marburg viruses, members of the Filoviridae, which cause severe hemorrhagic fevers in humans with no effective treatment and a mortality rate of up to 90%. Several vaccine strategies have been shown to effectively protect immunized animals against filovirus infection. Among these candidate vaccine strategies, virus-like particles represent a promising approach and have been shown to protect small laboratory animals as well as nonhuman primates against lethal challenge by Ebola and/or Marburg viruses. This review briefly summarizes filovirus epidemiology and pathogenesis, and focuses on the discussion of recent advances in filovirus vaccine development and the current understanding of protective immune responses against filovirus infection with an emphasis on the progress and challenge of filovirus virus-like particle vaccine development.
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Affiliation(s)
- Chinglai Yang
- Department of Microbiology and Immunology and Emory Vaccine Center, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322, USA.
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383
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Whole-genome expression profiling reveals that inhibition of host innate immune response pathways by Ebola virus can be reversed by a single amino acid change in the VP35 protein. J Virol 2008; 82:5348-58. [PMID: 18353943 DOI: 10.1128/jvi.00215-08] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Ebola hemorrhagic fever is a rapidly progressing acute febrile illness characterized by high virus replication, severe immunosuppression, and case fatalities of ca. 80%. Inhibition of phosphorylation of interferon regulatory factor 3 (IRF-3) by the Ebola VP35 protein may block the host innate immune response and play an important role in the severity of disease. We used two precisely defined reverse genetics-generated Ebola viruses to investigate global host cell responses resulting from the inhibition of IRF-3 phosphorylation. The two viruses encoded either wild-type (WT) VP35 protein (recEbo-VP35/WT) or VP35 with an arginine (R)-to-alanine (A) amino acid substitution at position 312 (recEbo-VP35/R312A) within a previously defined IRF-3 inhibitory domain. When sucrose-gradient purified virus was used for infection, host cell whole-genome expression profiling revealed striking differences in human liver cell responses to these viruses differing by a single amino acid. The inhibition of host innate immune responses by WT Ebola virus was so potent that little difference in interferon and antiviral gene expression could be discerned between cells infected with purified WT, inactivated virus, or mock-infected cells. However, infection with recEbo-VP35/R312A virus resulted in a strong innate immune response including increased expression of MDA-5, RIG-I, RANTES, MCP-1, ISG-15, ISG-54, ISG-56, ISG-60, STAT1, IRF-9, OAS, and Mx1. The clear gene expression differences were obscured if unpurified virus stocks were used to initiate infection, presumably due to soluble factors present in virus-infected cell supernatant preparations. Ebola virus VP35 protein clearly plays a pivotal role in the potent inhibition of the host innate immune responses, and the present study indicates that VP35 has a wider effect on host cell responses than previously shown. The ability to eliminate this inhibitory effect with a single amino acid change in VP35 demonstrates the critical role this protein must play in the severe aspects this highly fatal disease.
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384
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Bradfute SB, Warfield KL, Bavari S. Functional CD8+ T Cell Responses in Lethal Ebola Virus Infection. THE JOURNAL OF IMMUNOLOGY 2008; 180:4058-66. [DOI: 10.4049/jimmunol.180.6.4058] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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385
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Rubins KH, Hensley LE, Wahl-Jensen V, Daddario DiCaprio KM, Young HA, Reed DS, Jahrling PB, Brown PO, Relman DA, Geisbert TW. The temporal program of peripheral blood gene expression in the response of nonhuman primates to Ebola hemorrhagic fever. Genome Biol 2008; 8:R174. [PMID: 17725815 PMCID: PMC2375004 DOI: 10.1186/gb-2007-8-8-r174] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 05/04/2007] [Accepted: 08/28/2007] [Indexed: 11/15/2022] Open
Abstract
Primate blood cells were analysed for changes in global gene expression patterns at several time points following infection with Ebola virus, providing insights into potential mechanisms of viral pathogenesis and host defense. Background Infection with Ebola virus (EBOV) causes a fulminant and often fatal hemorrhagic fever. In order to improve our understanding of EBOV pathogenesis and EBOV-host interactions, we examined the molecular features of EBOV infection in vivo. Results Using high-density cDNA microarrays, we analyzed genome-wide host expression patterns in sequential blood samples from nonhuman primates infected with EBOV. The temporal program of gene expression was strikingly similar between animals. Of particular interest were features of the data that reflect the interferon response, cytokine signaling, and apoptosis. Transcript levels for tumor necrosis factor-α converting enzyme (TACE)/α-disintegrin and metalloproteinase (ADAM)-17 increased during days 4 to 6 after infection. In addition, the serum concentration of cleaved Ebola glycoprotein (GP2 delta) was elevated in late-stage EBOV infected animals. Of note, we were able to detect changes in gene expression of more than 300 genes before symptoms appeared. Conclusion These results provide the first genome-wide ex vivo analysis of the host response to systemic filovirus infection and disease. These data may elucidate mechanisms of viral pathogenesis and host defense, and may suggest targets for diagnostic and therapeutic development.
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Affiliation(s)
- Kathleen H Rubins
- Department of Microbiology and Immunology, 299 Campus Dr., Stanford University School of Medicine, Stanford, California 94305, USA
- Department of Biochemistry, 279 Campus Dr., Stanford University School of Medicine, Stanford, California 94305, USA
- Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, Massachusetts 02142, USA
| | - Lisa E Hensley
- US Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, Maryland 21702-5011, USA
| | - Victoria Wahl-Jensen
- US Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, Maryland 21702-5011, USA
| | - Kathleen M Daddario DiCaprio
- US Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, Maryland 21702-5011, USA
| | - Howard A Young
- National Cancer Institute - Frederick, 1050 Boyles St., Frederick, Maryland 21702, USA
| | - Douglas S Reed
- US Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, Maryland 21702-5011, USA
| | - Peter B Jahrling
- US Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, Maryland 21702-5011, USA
| | - Patrick O Brown
- Department of Biochemistry, 279 Campus Dr., Stanford University School of Medicine, Stanford, California 94305, USA
- Howard Hughes Medical Institute, 279 Campus Dr., Stanford University School of Medicine, Stanford, California 94305, USA
| | - David A Relman
- Department of Microbiology and Immunology, 299 Campus Dr., Stanford University School of Medicine, Stanford, California 94305, USA
- Department of Medicine, 300 Pasteur Dr., Stanford University School of Medicine, Stanford, California 94305, USA
- Veterans Affairs Palo Alto Health Care System, 3801 Miranda Ave., Palo Alto, California 94304, USA
| | - Thomas W Geisbert
- US Army Medical Research Institute of Infectious Diseases, 1425 Porter St., Fort Detrick, Maryland 21702-5011, USA
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386
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Bausch DG, Sprecher AG, Jeffs B, Boumandouki P. Treatment of Marburg and Ebola hemorrhagic fevers: a strategy for testing new drugs and vaccines under outbreak conditions. Antiviral Res 2008; 78:150-61. [PMID: 18336927 DOI: 10.1016/j.antiviral.2008.01.152] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 01/16/2008] [Accepted: 01/19/2008] [Indexed: 12/19/2022]
Abstract
The filoviruses, Marburg and Ebola, have the dubious distinction of being associated with some of the highest case-fatality rates of any known infectious disease--approaching 90% in many outbreaks. In recent years, laboratory research on the filoviruses has produced treatments and vaccines that are effective in laboratory animals and that could potentially drastically reduce case-fatality rates and curtail outbreaks in humans. However, there are significant challenges in clinical testing of these products and eventual delivery to populations in need. Most cases of filovirus infection are recognized only in the setting of large outbreaks, often in the most remote and resource-poor areas of sub-Saharan Africa, with little infrastructure and few personnel experienced in clinical research. Significant political, legal, and socio-cultural barriers also exist. Here, we review the present research priorities and environment for field study of the filovirus hemorrhagic fevers and outline a strategy for future prospective clinical research on treatment and vaccine prevention.
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Affiliation(s)
- Daniel G Bausch
- Tulane University Health Sciences Center, New Orleans, LA, United States.
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387
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Gramberg T, Soilleux E, Fisch T, Lalor PF, Hofmann H, Wheeldon S, Cotterill A, Wegele A, Winkler T, Adams DH, Pöhlmann S. Interactions of LSECtin and DC-SIGN/DC-SIGNR with viral ligands: Differential pH dependence, internalization and virion binding. Virology 2008; 373:189-201. [PMID: 18083206 PMCID: PMC7103327 DOI: 10.1016/j.virol.2007.11.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 10/15/2007] [Accepted: 11/02/2007] [Indexed: 01/20/2023]
Abstract
The calcium-dependent lectins DC-SIGN and DC-SIGNR (collectively termed DC-SIGN/R) bind to high-mannose carbohydrates on a variety of viruses. In contrast, the related lectin LSECtin does not recognize mannose-rich glycans and interacts with a more restricted spectrum of viruses. Here, we analyzed whether these lectins differ in their mode of ligand engagement. LSECtin and DC-SIGNR, which we found to be co-expressed by liver, lymph node and bone marrow sinusoidal endothelial cells, bound to soluble Ebola virus glycoprotein (EBOV-GP) with comparable affinities. Similarly, LSECtin, DC-SIGN and the Langerhans cell-specific lectin Langerin readily bound to soluble human immunodeficiency virus type-1 (HIV-1) GP. However, only DC-SIGN captured HIV-1 particles, indicating that binding to soluble GP is not necessarily predictive of binding to virion-associated GP. Capture of EBOV-GP by LSECtin triggered ligand internalization, suggesting that LSECtin like DC-SIGN might function as an antigen uptake receptor. However, the intracellular fate of lectin-ligand complexes might differ. Thus, exposure to low-pH medium, which mimics the acidic luminal environment in endosomes/lysosomes, released ligand bound to DC-SIGN/R but had no effect on LSECtin interactions with ligand. Our results reveal important differences between pathogen capture by DC-SIGN/R and LSECtin and hint towards different biological functions of these lectins.
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Affiliation(s)
- Thomas Gramberg
- Institute of Virology, University Hospital Erlangen, 91054 Erlangen, Germany
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388
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Malleret B, Karlsson I, Manéglier B, Brochard P, Delache B, Andrieu T, Muller-Trutwin M, Beaumont T, McCune JM, Banchereau J, Le Grand R, Vaslin B. Effect of SIVmac infection on plasmacytoid and CD1c+ myeloid dendritic cells in cynomolgus macaques. Immunology 2008; 124:223-33. [PMID: 18217951 DOI: 10.1111/j.1365-2567.2007.02758.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Dendritic cells (DCs) are known to be essential for the induction and regulation of immune responses. Non-human primates are essential in biomedical research and contribute to our understanding of the involvement of DCs in human infectious diseases. However, no direct single-platform method for quantifying DC precursors has yet been optimized in macaques to give accurate absolute blood counts of these rare-event cell populations in the blood. We adapted a rapid whole-blood assay for the absolute quantification of DCs in cynomolgus macaques by four-colour flow cytometry, using a single-platform assay compatible with human blood. Cynomolgus macaque plasmacytoid DCs (pDCs) and CD1c(+) myeloid DCs (CD1c(+) mDCs) were quantified in the blood of 34 healthy macaques and the results obtained were compared with those for blood samples from 11 healthy humans. In addition, circulating absolute numbers of pDCs were quantified in cynomolgus macaques chronically infected with SIVmac. During infection, pDC counts decreased whereas circulating CD1c(+) mDC counts increased. Information regarding absolute pDC and mDC counts in non-human primates may improve our understanding of the role of these cells in SIV/HIV infection and in other infectious diseases.
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Affiliation(s)
- Benoît Malleret
- CEA, Service d'Immuno-Virologie, DSV/iMETI, IPSC, Fontenay-aux-Roses, France
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389
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Hensley LE, Stevens EL, Yan SB, Geisbert JB, Macias WL, Larsen T, Daddario-DiCaprio KM, Cassell GH, Jahrling PB, Geisbert TW. Recombinant human activated protein C for the postexposure treatment of Ebola hemorrhagic fever. J Infect Dis 2008; 196 Suppl 2:S390-9. [PMID: 17940975 DOI: 10.1086/520598] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Infection of primates with Zaire ebolavirus (ZEBOV) leads to hypotension, coagulation disorders, and an impaired immune response and, in many ways, resembles severe sepsis. Rapid decreases in plasma levels of protein C are a prominent feature of severe sepsis and ZEBOV hemorrhagic fever (ZHF). Currently, recombinant human activated protein C (rhAPC [Xigris; Eli Lilly]) is licensed for treating human patients with severe sepsis who are at high risk of death. The aim of this study was to test the efficacy of rhAPC as a potential treatment for ZHF. METHODS Fourteen rhesus macaques were challenged with a uniformly lethal dose of ZEBOV; 11 of these monkeys were treated by intravenous infusion with rhAPC beginning 30-60 min after challenge and continuing for 7 days. Three control monkeys received sterile saline in parallel. RESULTS All 3 control monkeys died on day 8, whereas 2 of the 11 rhAPC-treated monkeys survived. The mean time to death for the rhAPC-treated monkeys that did not survive ZEBOV challenge was 12.6 days. The difference in survival was significant when the rhAPC-treated monkeys were compared with historical controls. CONCLUSIONS The experimental findings provide evidence that ZHF and severe sepsis share underlying mechanisms and may respond to the same therapies.
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Affiliation(s)
- Lisa E Hensley
- Virology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, MD, USA
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390
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Geisbert TW, Daddario-DiCaprio KM, Geisbert JB, Young HA, Formenty P, Fritz EA, Larsen T, Hensley LE. Marburg virus Angola infection of rhesus macaques: pathogenesis and treatment with recombinant nematode anticoagulant protein c2. J Infect Dis 2008; 196 Suppl 2:S372-81. [PMID: 17940973 PMCID: PMC7110112 DOI: 10.1086/520608] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
BACKGROUND The procoagulant tissue factor (TF) is thought to play a role in the coagulation disorders that characterize filoviral infections. In this study, we evaluated the pathogenesis of lethal infection with the Angola strain of Marburg virus (MARV-Ang) in rhesus macaques and tested the efficacy of recombinant nematode anticoagulant protein c2 (rNAPc2), an inhibitor of TF/factor VIIa, as a potential treatment. METHODS Twelve rhesus macaques were challenged with a high dose (1000 pfu) of MARV-Ang. Six macaques were treated with rNAPc2, and 6 macaques served as control animals. RESULTS All 6 control animals succumbed to MARV-Ang challenge by day 8 (mean, 7.3 days), whereas 5 of 6 rNAPc2-treated animals died on day 9 and 1 rNAPc2-treated animal survived. The disease course for MARV-Ang infection appeared to progress more rapidly in rhesus macaques than has been previously reported for other strains of MARV. In contrast to Ebola virus (EBOV) infection in macaques, up-regulation of TF was not as striking, and deposition of fibrin was a less prominent pathologic feature of disease in these animals. CONCLUSIONS These data show that the pathogenicity of MARV-Ang infection appears to be consistent with the apparent increased human virulence attributed to this strain. The apparent reduced efficacy of rNAPc2 against MARV-Ang infection, compared with its efficacy against EBOV infection, appears to be associated with differences in TF induction and fibrin deposition.
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Affiliation(s)
- Thomas W Geisbert
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD, USA.
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391
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Ebihara H, Theriault S, Neumann G, Alimonti JB, Geisbert JB, Hensley LE, Groseth A, Jones SM, Geisbert TW, Kawaoka Y, Feldmann H. In vitro and in vivo characterization of recombinant Ebola viruses expressing enhanced green fluorescent protein. J Infect Dis 2008; 196 Suppl 2:S313-22. [PMID: 17940966 DOI: 10.1086/520590] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
To facilitate an understanding of the molecular aspects of the pathogenesis of Zaire ebolavirus (ZEBOV) infection, we generated 2 different recombinant viruses expressing enhanced green fluorescent protein (eGFP) from additional transcription units inserted at different positions in the virus genome. These viruses showed in vitro phenotypes similar to that of wild-type ZEBOV (wt-ZEBOV) and were stable over multiple passages. Infection with one of the viruses expressing eGFP produced only mild disease in rhesus macaques, demonstrating a marked attenuation in this animal model. However, in mice lacking signal transducer and activator of transcription 1, both viruses expressing eGFP caused lethal cases of disease that were moderately attenuated, compared with that caused by wt-ZEBOV. In mice, viral replication could be easily tracked by the detection of eGFP-positive cells in tissues, by use of flow cytometry. These findings demonstrate that the incorporation of a foreign gene will attenuate ZEBOV in vivo but that these viruses still have potential for in vitro and in vivo research applications.
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Affiliation(s)
- Hideki Ebihara
- Department of Special Pathogens, International Research Center for Infectious Diseases, University of Tokyo, Tokyo, Japan.
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392
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Marzi A, Möller P, Hanna SL, Harrer T, Eisemann J, Steinkasserer A, Becker S, Baribaud F, Pöhlmann S. Analysis of the interaction of Ebola virus glycoprotein with DC-SIGN (dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin) and its homologue DC-SIGNR. J Infect Dis 2008; 196 Suppl 2:S237-46. [PMID: 17940955 PMCID: PMC7110133 DOI: 10.1086/520607] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The lectin DC-SIGN (dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin) augments Ebola virus (EBOV) infection. However, it its unclear whether DC-SIGN promotes only EBOV attachment (attachment factor function, nonessential) or actively facilitates EBOV entry (receptor function, essential). METHODS We investigated whether DC-SIGN on B cell lines and dendritic cells acts as an EBOV attachment factor or receptor. RESULTS Engineered DC-SIGN expression rendered some B cell lines susceptible to EBOV glycoprotein (EBOV GP)-driven infection, whereas others remained refractory, suggesting that cellular factors other than DC-SIGN are also required for susceptibility to EBOV infection. Augmentation of entry was independent of efficient DC-SIGN internalization and might not involve lectin-mediated endocytic uptake of virions. Therefore, DC-SIGN is unlikely to function as an EBOV receptor on B cell lines; instead, it might concentrate virions onto cells, thereby allowing entry into cell lines expressing low levels of endogenous receptor(s). Indeed, artificial concentration of virions onto cells mirrored DC-SIGN expression, confirming that optimization of viral attachment is sufficient for EBOV GP-driven entry into some B cell lines. Finally, EBOV infection of dendritic cells was only partially dependent on mannose-specific lectins, such as DC-SIGN, suggesting an important contribution of other factors. CONCLUSIONS Our results indicate that DC-SIGN is not an EBOV receptor but, rather, is an attachment-promoting factor that boosts entry into B cell lines susceptible to low levels of EBOV GP-mediated infection.
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Affiliation(s)
- Andrea Marzi
- Institute of Virology, Nikolaus-Fiebiger-Center for Molecular Medicine, Erlangen, Germany
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393
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Sanchez A. Analysis of filovirus entry into vero e6 cells, using inhibitors of endocytosis, endosomal acidification, structural integrity, and cathepsin (B and L) activity. J Infect Dis 2008; 196 Suppl 2:S251-8. [PMID: 17940957 DOI: 10.1086/520597] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Ebola and Marburg viruses are believed to enter host cells by receptor-mediated endocytosis. The process has been studied through the use of inhibitors that affect host cell properties and recombinant pseudotyping systems in which filovirus structural glycoproteins mediate entry of foreign virus particles. The aim of the present study was to determine the effects of such treatments on the entry of wild-type filoviruses. Vero E6 cells were exposed to various inhibitors before, during, and after infection with filoviruses. Infected cultures were harvested early (18-24 h) and late (72 h) after infection, and effects of treatment on entry were measured by fluorescent antibody staining of cells or by antigen capture immunoassays, respectively. These prelimary results suggest that filoviruses enter host cells through receptor-mediated endocytosis via clathrin-coated pits and caveolae, that actin filaments and microtubules are important in the entry process, and that proteolytic digestion of glycoprotein 1 by endosomal proteases facilitates entry. These observations obtained using wild-type viruses confirm the results of studies utilizing recombinant systems and offer additional insights into filovirus entry.
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Affiliation(s)
- Anthony Sanchez
- Special Pathogens Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
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394
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Vaccine to confer to nonhuman primates complete protection against multistrain Ebola and Marburg virus infections. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2008; 15:460-7. [PMID: 18216185 DOI: 10.1128/cvi.00431-07] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Filoviruses (Ebola and Marburg viruses) are among the deadliest viruses known to mankind, with mortality rates nearing 90%. These pathogens are highly infectious through contact with infected body fluids and can be easily aerosolized. Additionally, there are currently no licensed vaccines available to prevent filovirus outbreaks. Their high mortality rates and infectious capabilities when aerosolized and the lack of licensed vaccines available to prevent such infectious make Ebola and Marburg viruses serious bioterrorism threats, placing them both on the category A list of bioterrorism agents. Here we describe a panfilovirus vaccine based on a complex adenovirus (CAdVax) technology that expresses multiple antigens from five different filoviruses de novo. Vaccination of nonhuman primates demonstrated 100% protection against infection by two species of Ebola virus and three Marburg virus subtypes, each administered at 1,000 times the lethal dose. This study indicates the feasibility of vaccination against all current filovirus threats in the event of natural hemorrhagic fever outbreak or biological attack.
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395
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Abstract
Ebola virus is a highly virulent pathogen capable of inducing a frequently lethal hemorrhagic fever syndrome. Accumulating evidence indicates that the virus actively subverts both innate and adaptive immune responses and triggers harmful inflammatory responses as it inflicts direct tissue damage. The host immune system is ultimately overwhelmed by a combination of inflammatory factors and virus-induced cell damage, particularly in the liver and vasculature, often leading to death from septic shock. We summarize the mechanisms of immune dysregulation and virus-mediated cell damage in Ebola virus–infected patients. Future approaches to prevention and treatment of infection will be guided by answers to unresolved questions about interspecies transmission, molecular mechanisms of pathogenesis, and protective adaptive and innate immune responses to Ebola virus.
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396
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Ebola vaccines. Vaccines (Basel) 2008. [DOI: 10.1016/b978-1-4160-3611-1.50049-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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397
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Hutchinson K, Rollin P. Cytokine and Chemokine Expression in Humans Infected with Sudan Ebola Virus. J Infect Dis 2007; 196 Suppl 2:S357-63. [DOI: 10.1086/520611] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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398
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Böckeler M, Ströher U, Seebach J, Afanasieva T, Suttorp N, Feldmann H, Schnittler H. Breakdown of Paraendothelial Barrier Function during Marburg Virus Infection Is Associated with Early Tyrosine Phosphorylation of Platelet Endothelial Cell Adhesion Molecule–1. J Infect Dis 2007; 196 Suppl 2:S337-46. [DOI: 10.1086/520606] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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399
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Larsen T, Stevens E, Davis K, Geisbert J, Daddario‐DiCaprio K, Jahrling P, Hensley L, Geisbert T. Pathologic Findings Associated with Delayed Death in Nonhuman Primates Experimentally Infected with Zaire Ebola Virus. J Infect Dis 2007; 196 Suppl 2:S323-8. [DOI: 10.1086/520589] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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400
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Rollin P, Bausch D, Sanchez A. Blood Chemistry Measurements andd‐Dimer Levels Associated with Fatal and Nonfatal Outcomes in Humans Infected with Sudan Ebola Virus. J Infect Dis 2007; 196 Suppl 2:S364-71. [DOI: 10.1086/520613] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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