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Development of Virus-Like-Particle Vaccine and Reporter Assay for Zika Virus. J Virol 2017; 91:JVI.00834-17. [PMID: 28794019 DOI: 10.1128/jvi.00834-17] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/31/2017] [Indexed: 12/31/2022] Open
Abstract
Recent worldwide outbreaks of Zika virus (ZIKV) infection and the lack of an approved vaccine raise serious concerns regarding preparedness to combat this emerging virus. We used a virus-like particle (VLP)-based approach to develop a vaccine and a microneutralization assay for ZIKV. A synthetic capsid-premembrane-envelope (C-prM-E) gene construct of ZIKV was used to generate reporter virus particles (RVPs) that package a green fluorescent protein (GFP) reporter-expressing West Nile virus (WNV) replicon. The assay was adapted to a 96-well format, similar to the plaque reduction neutralization test (PRNT), and showed high reproducibility with specific detection of ZIKV neutralizing antibodies. Furthermore, C-prM-E and prM-E VLPs were tested as vaccine candidates in mice and compared to DNA vaccination. While the ZIKV prM-E construct alone was sufficient for generating VLPs, efficient VLP production from the C-prM-E construct could be achieved in the presence of the WNV NS2B-3 protease, which cleaves C from prM, allowing virus release. Immunization studies in mice showed that VLPs generated higher neutralizing antibody titers than those with the DNA vaccines, with C-prM-E VLPs giving slightly higher titers than those with prM-E VLPs. The superiority of C-prM-E VLPs suggests that inclusion of capsid may have benefits for ZIKV and other flaviviral VLP vaccines. To facilitate the VLP platform, we generated a stable cell line expressing high levels of ZIKV prM-E proteins that constitutively produce VLPs as well as a cell line expressing ZIKV C-prM-E proteins for RVP production. While several vaccine platforms have been proposed for ZIKV, this study describes a safe, effective, and economical VLP-based vaccine against ZIKV.IMPORTANCE To address the growing Zika virus epidemic, we undertook this study with two objectives: first, to develop a safe, effective, and economical vaccine for ZIKV, and second, to develop a rapid and versatile assay to detect the anti-ZIKV immune response. We generated a cell line stably expressing ZIKV prM-E that produces large amounts of VLPs in the supernatant and a ZIKV C-prM-E cell line that produces reporter virus particles upon transfection with a GFP replicon plasmid. The prM-E VLPs induced a strong neutralizing antibody response in mice that was better when the capsid was included. VLP-based vaccines showed significantly better neutralizing antibody responses than those with their DNA counterparts. The RVP-based microneutralization assay worked similarly to the PRNT assay, with a rapid GFP readout in a 96-well format. Our VLP-based platform provides a source for a ZIKV vaccine and diagnosis that can rapidly be adapted to current outbreaks.
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Abstract
What are the features of partitioning of crystalline materials on the surface of a two-component icosahedral vesicle? We model the response of the rigid hardly stretchable crystalline icosahedra upon addition of a softer component on its surface. We demonstrate how the soft phase "invades" the shell regions with the highest elastic energy density around 12 5-fold topological defects. We explore the phase diagram of these inhomogeneous shells as a function of the soft material fraction, shell radius, and elastic moduli of the two phases. The findings are compared with the recent computer simulation findings, and their biological relevance, for example, for the structure of icosahedral viruses, is also discussed.
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Affiliation(s)
- Andrey G Cherstvy
- Institute for Physics & Astronomy, University of Potsdam , 14476 Potsdam-Golm, Germany.,IAS-2 Institute, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
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Richner JM, Jagger BW, Shan C, Fontes CR, Dowd KA, Cao B, Himansu S, Caine EA, Nunes BT, Medeiros DB, Muruato AE, Foreman BM, Luo H, Wang T, Barrett AD, Weaver SC, Vasconcelos PF, Rossi SL, Ciaramella G, Mysorekar IU, Pierson TC, Shi PY, Diamond MS. Vaccine Mediated Protection Against Zika Virus-Induced Congenital Disease. Cell 2017; 170:273-283.e12. [PMID: 28708997 PMCID: PMC5546158 DOI: 10.1016/j.cell.2017.06.040] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/19/2017] [Accepted: 06/26/2017] [Indexed: 12/11/2022]
Abstract
The emergence of Zika virus (ZIKV) and its association with congenital malformations has prompted the rapid development of vaccines. Although efficacy with multiple viral vaccine platforms has been established in animals, no study has addressed protection during pregnancy. We tested in mice two vaccine platforms, a lipid nanoparticle-encapsulated modified mRNA vaccine encoding ZIKV prM and E genes and a live-attenuated ZIKV strain encoding an NS1 protein without glycosylation, for their ability to protect against transmission to the fetus. Vaccinated dams challenged with a heterologous ZIKV strain at embryo day 6 (E6) and evaluated at E13 showed markedly diminished levels of viral RNA in maternal, placental, and fetal tissues, which resulted in protection against placental damage and fetal demise. As modified mRNA and live-attenuated vaccine platforms can restrict in utero transmission of ZIKV in mice, their further development in humans to prevent congenital ZIKV syndrome is warranted.
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Affiliation(s)
- Justin M. Richner
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Brett W. Jagger
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Chao Shan
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Camila R. Fontes
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Kimberly A. Dowd
- Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD 20892 USA
| | - Bin Cao
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sunny Himansu
- Valera LLC, a Moderna Venture, 500 Technology Square, Cambridge, MA, 02139, USA
| | - Elizabeth A. Caine
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bruno T.D. Nunes
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará State, Brazil
| | - Daniele B.A. Medeiros
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará State, Brazil
| | - Antonio E. Muruato
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Bryant M. Foreman
- Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD 20892 USA
| | - Huanle Luo
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Tian Wang
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Alan D. Barrett
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Scott C. Weaver
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
- Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Pedro F.C. Vasconcelos
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará State, Brazil
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA, Department of Pathology, Pará State University, Belém, Brazil
| | - Shannan L. Rossi
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Giuseppe Ciaramella
- Valera LLC, a Moderna Venture, 500 Technology Square, Cambridge, MA, 02139, USA
| | - Indira U. Mysorekar
- Department of Obstetrics and Gynecology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA, Department of Pathology, Pará State University, Belém, Brazil
| | - Theodore C. Pierson
- Viral Pathogenesis Section, National Institutes of Health, Bethesda, MD 20892 USA
| | - Pei-Yong Shi
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Translational Science, University of Texas Medical Branch, Galveston, TX 77555, USA
- Institute for Human infections and Immunity, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Michael S. Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA, Department of Pathology, Pará State University, Belém, Brazil
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- The Andrew M. and Jane M. Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, MO 63110, USA
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Gerold G, Bruening J, Weigel B, Pietschmann T. Protein Interactions during the Flavivirus and Hepacivirus Life Cycle. Mol Cell Proteomics 2017; 16:S75-S91. [PMID: 28077444 DOI: 10.1074/mcp.r116.065649] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 01/11/2017] [Indexed: 12/28/2022] Open
Abstract
Protein-protein interactions govern biological functions in cells, in the extracellular milieu, and at the border between cells and extracellular space. Viruses are small intracellular parasites and thus rely on protein interactions to produce progeny inside host cells and to spread from cell to cell. Usage of host proteins by viruses can have severe consequences e.g. apoptosis, metabolic disequilibria, or altered cell proliferation and mobility. Understanding protein interactions during virus infection can thus educate us on viral infection and pathogenesis mechanisms. Moreover, it has led to important clinical translations, including the development of new therapeutic and vaccination strategies. Here, we will discuss protein interactions of members of the Flaviviridae family, which are small enveloped RNA viruses. Dengue virus, Zika virus and hepatitis C virus belong to the most prominent human pathogenic Flaviviridae With a genome of roughly ten kilobases encoding only ten viral proteins, Flaviviridae display intricate mechanisms to engage the host cell machinery for their purpose. In this review, we will highlight how dengue virus, hepatitis C virus, Japanese encephalitis virus, tick-borne encephalitis virus, West Nile virus, yellow fever virus, and Zika virus proteins engage host proteins and how this knowledge helps elucidate Flaviviridae infection. We will specifically address the protein composition of the virus particle as well as the protein interactions during virus entry, replication, particle assembly, and release from the host cell. Finally, we will give a perspective on future challenges in Flaviviridae interaction proteomics and why we believe these challenges should be met.
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Affiliation(s)
- Gisa Gerold
- From the Institute for Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hannover, Germany
| | - Janina Bruening
- From the Institute for Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hannover, Germany
| | - Bettina Weigel
- From the Institute for Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hannover, Germany
| | - Thomas Pietschmann
- From the Institute for Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Medical School Hannover and the Helmholtz Centre for Infection Research, Hannover, Germany
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55
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Gallagher JR, Torian U, McCraw DM, Harris AK. Characterization of the disassembly and reassembly of the HBV glycoprotein surface antigen, a pliable nanoparticle vaccine platform. Virology 2017; 502:176-187. [PMID: 28061386 DOI: 10.1016/j.virol.2016.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 12/10/2016] [Accepted: 12/20/2016] [Indexed: 01/19/2023]
Abstract
While nanoparticle vaccine technology is gaining interest due to the success of vaccines like those for the human papillomavirus that is based on viral capsid nanoparticles, little information is available on the disassembly and reassembly of viral surface glycoprotein-based nanoparticles. One such particle is the hepatitis B virus surface antigen (sAg) that exists as nanoparticles. Here we show, using biochemical analysis coupled with electron microscopy, that sAg nanoparticle disassembly requires both reducing agent to disrupt intermolecular disulfide bonds, and detergent to disrupt hydrophobic interactions that stabilize the nanoparticle. Particles were otherwise resistant to salt and urea, suggesting the driving mechanism of particle formation involves hydrophobic interactions. We reassembled isolated sAg protein into nanoparticles by detergent removal and reassembly resulted in a wider distribution of particle diameters. Knowledge of these driving forces of nanoparticle assembly and stability should facilitate construction of epitope-displaying nanoparticles that can be used as immunogens in vaccines.
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Affiliation(s)
- John R Gallagher
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive, Room 6351, Bethesda, MD 20892, USA
| | - Udana Torian
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive, Room 6351, Bethesda, MD 20892, USA
| | - Dustin M McCraw
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive, Room 6351, Bethesda, MD 20892, USA
| | - Audray K Harris
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 50 South Drive, Room 6351, Bethesda, MD 20892, USA.
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56
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The flavivirus capsid protein: Structure, function and perspectives towards drug design. Virus Res 2017; 227:115-123. [DOI: 10.1016/j.virusres.2016.10.005] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 09/29/2016] [Accepted: 10/12/2016] [Indexed: 12/12/2022]
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57
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Ekins S, Liebler J, Neves BJ, Lewis WG, Coffee M, Bienstock R, Southan C, Andrade CH. Illustrating and homology modeling the proteins of the Zika virus. F1000Res 2016; 5:275. [PMID: 27746901 DOI: 10.12688/f1000research.8213.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/29/2016] [Indexed: 12/28/2022] Open
Abstract
The Zika virus (ZIKV) is a flavivirus of the family Flaviviridae, which is similar to dengue virus, yellow fever and West Nile virus. Recent outbreaks in South America, Latin America, the Caribbean and in particular Brazil have led to concern for the spread of the disease and potential to cause Guillain-Barré syndrome and microcephaly. Although ZIKV has been known of for over 60 years there is very little in the way of knowledge of the virus with few publications and no crystal structures. No antivirals have been tested against it either in vitro or in vivo. ZIKV therefore epitomizes a neglected disease. Several suggested steps have been proposed which could be taken to initiate ZIKV antiviral drug discovery using both high throughput screens as well as structure-based design based on homology models for the key proteins. We now describe preliminary homology models created for NS5, FtsJ, NS4B, NS4A, HELICc, DEXDc, peptidase S7, NS2B, NS2A, NS1, E stem, glycoprotein M, propeptide, capsid and glycoprotein E using SWISS-MODEL. Eleven out of 15 models pass our model quality criteria for their further use. While a ZIKV glycoprotein E homology model was initially described in the immature conformation as a trimer, we now describe the mature dimer conformer which allowed the construction of an illustration of the complete virion. By comparing illustrations of ZIKV based on this new homology model and the dengue virus crystal structure we propose potential differences that could be exploited for antiviral and vaccine design. The prediction of sites for glycosylation on this protein may also be useful in this regard. While we await a cryo-EM structure of ZIKV and eventual crystal structures of the individual proteins, these homology models provide the community with a starting point for structure-based design of drugs and vaccines as well as a for computational virtual screening.
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Affiliation(s)
- Sean Ekins
- Collaborations in Chemistry, Fuquay-Varina, NC, USA; Collaborations Pharmaceuticals Inc., Fuquay-Varina, NC, USA; Collaborative Drug Discovery Inc, Burlingame, CA, USA
| | | | - Bruno J Neves
- LabMol - Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, GO, Brazil
| | - Warren G Lewis
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Megan Coffee
- The International Rescue Committee, New York, NY, USA
| | | | | | - Carolina H Andrade
- LabMol - Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, GO, Brazil
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Dowd KA, Ko SY, Morabito KM, Yang ES, Pelc RS, DeMaso CR, Castilho LR, Abbink P, Boyd M, Nityanandam R, Gordon DN, Gallagher JR, Chen X, Todd JP, Tsybovsky Y, Harris A, Huang YJS, Higgs S, Vanlandingham DL, Andersen H, Lewis MG, De La Barrera R, Eckels KH, Jarman RG, Nason MC, Barouch DH, Roederer M, Kong WP, Mascola JR, Pierson TC, Graham BS. Rapid development of a DNA vaccine for Zika virus. Science 2016; 354:237-240. [PMID: 27708058 PMCID: PMC5304212 DOI: 10.1126/science.aai9137] [Citation(s) in RCA: 312] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 09/15/2016] [Indexed: 12/26/2022]
Abstract
Zika virus (ZIKV) was identified as a cause of congenital disease during the explosive outbreak in the Americas and Caribbean that began in 2015. Because of the ongoing fetal risk from endemic disease and travel-related exposures, a vaccine to prevent viremia in women of childbearing age and their partners is imperative. We found that vaccination with DNA expressing the premembrane and envelope proteins of ZIKV was immunogenic in mice and nonhuman primates, and protection against viremia after ZIKV challenge correlated with serum neutralizing activity. These data not only indicate that DNA vaccination could be a successful approach to protect against ZIKV infection, but also suggest a protective threshold of vaccine-induced neutralizing activity that prevents viremia after acute infection.
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Affiliation(s)
- Kimberly A Dowd
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sung-Youl Ko
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kaitlyn M Morabito
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Eun Sung Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rebecca S Pelc
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christina R DeMaso
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Leda R Castilho
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA. Federal University of Rio de Janeiro, COPPE (Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia), Chemical Engineering Program, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Peter Abbink
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Michael Boyd
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Ramya Nityanandam
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - David N Gordon
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John Robert Gallagher
- Structural Informatics Unit, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xuejun Chen
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John-Paul Todd
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yaroslav Tsybovsky
- Electron Microscopy Laboratory, Cancer Research Technology Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Audray Harris
- Structural Informatics Unit, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Yan-Jang S Huang
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Stephen Higgs
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | - Dana L Vanlandingham
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
| | | | | | - Rafael De La Barrera
- Translational Medicine Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Kenneth H Eckels
- Translational Medicine Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Richard G Jarman
- Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Martha C Nason
- Biostatistics Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20852, USA
| | - Dan H Barouch
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Mario Roederer
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Wing-Pui Kong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - John R Mascola
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Theodore C Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Barney S Graham
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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Pseudo-typed Semliki Forest virus delivers EGFP into neurons. J Neurovirol 2016; 23:205-215. [PMID: 27739033 DOI: 10.1007/s13365-016-0486-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 09/22/2016] [Accepted: 09/26/2016] [Indexed: 12/14/2022]
Abstract
Semliki Forest virus (SFV), a neurotropic virus, has been used to deliver heterologous genes into cells in vitro and in vivo. In this study, we constructed a reporter SFV4-FL-EGFP and found that it can deliver EGFP into neurons located at the injection site without disseminating throughout the brain. Lacking of the capsid gene of SFV4-FL-EGFP does not block its life cycle, while forming replication-competent virus-like particles (VLPs). These VLPs hold subviral genome by using the packaging sequence (PS) located within the nsP2 gene, and can transfer their genome into cells. In addition, we found that the G protein of vesicular stomatitis virus (VSVG) can package SFV subviral genome, which is consistent with the previous reports. The G protein of rabies virus (RVG) could also package SFV subviral genome. These pseudo-typed SFV can deliver EGFP gene into neurons. Taken together, these findings may be used to construct various SFV-based delivery systems for virological studies, gene therapy, and neural circuit labeling.
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Blazevic J, Rouha H, Bradt V, Heinz FX, Stiasny K. Membrane Anchors of the Structural Flavivirus Proteins and Their Role in Virus Assembly. J Virol 2016; 90:6365-6378. [PMID: 27147734 PMCID: PMC4936158 DOI: 10.1128/jvi.00447-16] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 04/22/2016] [Indexed: 12/23/2022] Open
Abstract
UNLABELLED The structural proteins of flaviviruses carry a unique set of transmembrane domains (TMDs) at their C termini that are derived from the mode of viral polyprotein processing. They function as internal signal and stop-transfer sequences during protein translation, but possible additional roles in protein interactions required during assembly and maturation of viral particles are ill defined. To shed light on the role of TMDs in these processes, we engineered a set of tick-borne encephalitis virus mutants in which these structural elements were replaced in different combinations by the homologous sequences of a distantly related flavivirus (Japanese encephalitis virus). The effects of these modifications were analyzed with respect to protein synthesis, viral particle secretion, specific infectivity, and acidic-pH-induced maturation processes. We provide evidence that interactions involving the double-membrane anchor of the envelope protein E (a unique feature compared to other viral fusion proteins) contribute substantially to particle assembly, stability, and maturation. Disturbances of the inter- and intra-TMD interactions of E resulted in the secretion of a larger proportion of capsidless subviral particles at the expense of whole virions, suggesting a possible role in the still incompletely understood mechanism of capsid integration during virus budding. In contrast, the TMD initially anchoring the C protein to the endoplasmic reticulum membrane does not appear to take part in envelope protein interactions. We also show that E TMDs are involved in the envelope protein rearrangements that are triggered by acidic pH in the trans-Golgi network and represent a hallmark of virus maturation. IMPORTANCE The assembly of flaviviruses occurs in the endoplasmic reticulum and leads to the formation of immature, noninfectious particles composed of an RNA-containing capsid surrounded by a lipid membrane, with the two integrated envelope proteins, prM and E, arranged in an icosahedral lattice. The mechanism by which the capsid is formed and integrated into the budding viral envelope is currently unknown. We provide evidence that the transmembrane domains (TMDs) of E are essential for the formation of capsid-containing particles and that disturbances of these interactions lead to the preferential formation of capsidless subviral particles at the expense of whole virions. E TMD interactions also appear to be essential for the envelope protein rearrangements required for virus maturation and for the generation of infectious virions. Our data thus provide new insights into the biological functions of E TMDs and extend their role during viral polyprotein processing to additional functions in particle assembly and maturation.
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Affiliation(s)
- Janja Blazevic
- Department of Virology, Medical University of Vienna, Vienna, Austria
| | - Harald Rouha
- Department of Virology, Medical University of Vienna, Vienna, Austria
| | - Victoria Bradt
- Department of Virology, Medical University of Vienna, Vienna, Austria
| | - Franz X Heinz
- Department of Virology, Medical University of Vienna, Vienna, Austria
| | - Karin Stiasny
- Department of Virology, Medical University of Vienna, Vienna, Austria
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Inagaki E, Sakai M, Hirano M, Muto M, Kobayashi S, Kariwa H, Yoshii K. Development of a serodiagnostic multi-species ELISA against tick-borne encephalitis virus using subviral particles. Ticks Tick Borne Dis 2016; 7:723-729. [DOI: 10.1016/j.ttbdis.2016.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 02/22/2016] [Accepted: 03/01/2016] [Indexed: 11/29/2022]
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Bivalent vaccine platform based on Japanese encephalitis virus (JEV) elicits neutralizing antibodies against JEV and hepatitis C virus. Sci Rep 2016; 6:28688. [PMID: 27345289 PMCID: PMC4922013 DOI: 10.1038/srep28688] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/08/2016] [Indexed: 12/20/2022] Open
Abstract
Directly acting antivirals recently have become available for the treatment of hepatitis C virus (HCV) infection, but there is no prophylactic vaccine for HCV. In the present study, we took advantage of the properties of Japanese encephalitis virus (JEV) to develop antigens for use in a HCV vaccine. Notably, the surface-exposed JEV envelope protein is tolerant of inserted foreign epitopes, permitting display of novel antigens. We identified 3 positions that permitted insertion of the HCV E2 neutralization epitope recognized by HCV1 antibody. JEV subviral particles (SVP) containing HCV-neutralization epitope (SVP-E2) were purified from culture supernatant by gel chromatography. Sera from mice immunized with SVP-E2 inhibited infection by JEV and by trans-complemented HCV particles (HCVtcp) derived from multi-genotypic viruses, whereas sera from mice immunized with synthetic E2 peptides did not show any neutralizing activity. Furthermore, sera from mice immunized with SVP-E2 neutralized HCVtcp with N415K escape mutation in E2. As with the SVP-E2 epitope-displaying particles, JEV SVPs with HCV E1 epitope also elicited neutralizing antibodies against HCV. Thus, this novel platform harboring foreign epitopes on the surface of the particle may facilitate the development of a bivalent vaccine against JEV and other pathogens.
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Clark KB, Hsiao HM, Bassit L, Crowe JE, Schinazi RF, Perng GC, Villinger F. Characterization of dengue virus 2 growth in megakaryocyte-erythrocyte progenitor cells. Virology 2016; 493:162-72. [PMID: 27058763 DOI: 10.1016/j.virol.2016.03.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 03/26/2016] [Accepted: 03/28/2016] [Indexed: 10/22/2022]
Abstract
Megakaryocyte-erythrocyte progenitor (MEP) cells are potential in vivo targets of dengue virus (DENV); the virus has been found associated with megakaryocytes ex vivo and platelets during DENV-induced thrombocytopenia. We report here that DENV serotype 2 (DENV2) propagates well in human nondifferentiated MEP cell lines (Meg01 and K562). In comparison to virus propagated in Vero cells, viruses from MEP cell lines had similar structure and buoyant density. However, differences in MEP-DENV2 stability and composition were suggested by distinct protein patterns in western blot analysis. Also, antibody neutralization of envelope domain I/II on MEP-DENV2 was reduced relative to that on Vero-DENV2. Infectious DENV2 was produced at comparable kinetics and magnitude in MEP and Vero cells. However, fewer virion structures appeared in electron micrographs of MEP cells. We propose that DENV2 infects and produces virus efficiently in megakaryocytes and that megakaryocyte impairment might contribute to dengue disease pathogenesis.
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Affiliation(s)
- Kristina B Clark
- Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Hui-Mien Hsiao
- Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, GA, USA
| | - Leda Bassit
- Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, GA, USA
| | - James E Crowe
- Departments of Pediatrics, Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN, USA
| | - Raymond F Schinazi
- Center for AIDS Research, Department of Pediatrics, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, GA, USA
| | - Guey Chuen Perng
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Francois Villinger
- Division of Microbiology and Immunology, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; New Iberia Research Center, University of Louisiana at Lafayette, New Iberia, LA, USA
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64
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A recombinant DNA vaccine protects mice deficient in the alpha/beta interferon receptor against lethal challenge with Usutu virus. Vaccine 2016; 34:2066-73. [DOI: 10.1016/j.vaccine.2016.03.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/01/2016] [Accepted: 03/06/2016] [Indexed: 12/31/2022]
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65
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Ekins S, Liebler J, Neves BJ, Lewis WG, Coffee M, Bienstock R, Southan C, Andrade CH. Illustrating and homology modeling the proteins of the Zika virus. F1000Res 2016; 5:275. [PMID: 27746901 PMCID: PMC5040154 DOI: 10.12688/f1000research.8213.2] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/30/2016] [Indexed: 12/20/2022] Open
Abstract
The Zika virus (ZIKV) is a flavivirus of the family
Flaviviridae, which is similar to dengue virus, yellow fever and West Nile virus. Recent outbreaks in South America, Latin America, the Caribbean and in particular Brazil have led to concern for the spread of the disease and potential to cause Guillain-Barré syndrome and microcephaly. Although ZIKV has been known of for over 60 years there is very little in the way of knowledge of the virus with few publications and no crystal structures. No antivirals have been tested against it either
in vitro or
in vivo. ZIKV therefore epitomizes a neglected disease. Several suggested steps have been proposed which could be taken to initiate ZIKV antiviral drug discovery using both high throughput screens as well as structure-based design based on homology models for the key proteins. We now describe preliminary homology models created for NS5, FtsJ, NS4B, NS4A, HELICc, DEXDc, peptidase S7, NS2B, NS2A, NS1, E stem, glycoprotein M, propeptide, capsid and glycoprotein E using SWISS-MODEL. Eleven out of 15 models pass our model quality criteria for their further use. While a ZIKV glycoprotein E homology model was initially described in the immature conformation as a trimer, we now describe the mature dimer conformer which allowed the construction of an illustration of the complete virion. By comparing illustrations of ZIKV based on this new homology model and the dengue virus crystal structure we propose potential differences that could be exploited for antiviral and vaccine design. The prediction of sites for glycosylation on this protein may also be useful in this regard. While we await a cryo-EM structure of ZIKV and eventual crystal structures of the individual proteins, these homology models provide the community with a starting point for structure-based design of drugs and vaccines as well as a for computational virtual screening.
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Affiliation(s)
- Sean Ekins
- Collaborations in Chemistry, Fuquay-Varina, NC, USA; Collaborations Pharmaceuticals Inc., Fuquay-Varina, NC, USA; Collaborative Drug Discovery Inc, Burlingame, CA, USA
| | | | - Bruno J Neves
- LabMol - Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, GO, Brazil
| | - Warren G Lewis
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Megan Coffee
- The International Rescue Committee, New York, NY, USA
| | | | | | - Carolina H Andrade
- LabMol - Laboratory for Molecular Modeling and Drug Design, Faculty of Pharmacy, Federal University of Goias, GO, Brazil
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Suphatrakul A, Yasanga T, Keelapang P, Sriburi R, Roytrakul T, Pulmanausahakul R, Utaipat U, Kawilapan Y, Puttikhunt C, Kasinrerk W, Yoksan S, Auewarakul P, Malasit P, Charoensri N, Sittisombut N. Generation and preclinical immunogenicity study of dengue type 2 virus-like particles derived from stably transfected mosquito cells. Vaccine 2015; 33:5613-5622. [PMID: 26382602 DOI: 10.1016/j.vaccine.2015.08.090] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 08/02/2015] [Accepted: 08/30/2015] [Indexed: 10/23/2022]
Abstract
Recent phase IIb/III trials of a tetravalent live attenuated vaccine candidate revealed a need for improvement in the stimulation of protective immunity against diseases caused by dengue type 2 virus (DENV-2). Our attempts to develop particulate antigens for possibly supplementing live attenuated virus preparation involve generation and purification of recombinant DENV-2 virus-like particles (VLPs) derived from stably (prM+E)-expressing mosquito cells. Two VLP preparations generated with either negligible or enhanced prM cleavage exhibited different proportions of spherical particles and tubular particles of variable lengths. In BALB/c mice, VLPs were moderately immunogenic, requiring adjuvants for the induction of strong virus neutralizing antibody responses. VLPs with enhanced prM cleavage induced higher levels of neutralizing antibody than those without, but the stimulatory activity of both VLPs was similar in the presence of adjuvants. Comparison of EDIII-binding antibodies in mice following two adjuvanted doses of these VLPs revealed subtle differences in the stimulation of anti-EDIII binding antibodies. In cynomolgus macaques, VLPs with enhanced prM cleavage augmented strongly neutralizing antibody and EDIII-binding antibody responses in live attenuated virus-primed recipients, suggesting that these DENV-2 VLPs may be useful as the boosting antigen in prime-boost immunization. As the levels of neutralizing antibody induced in macaques with the prime-boost immunization were comparable to those infected with wild type virus, this virus-prime VLP-boost regimen may provide an immunization platform in which a need for robust neutralizing antibody response in the protection against DENV-2-associated illnesses could be tested.
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Affiliation(s)
- Amporn Suphatrakul
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10700, Thailand
| | - Thippawan Yasanga
- Medical Science Research Equipment Center, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Poonsook Keelapang
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Rungtawan Sriburi
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Thaneeya Roytrakul
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10700, Thailand; Dengue Hemorrhagic Fever Research Unit, Office of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | | | - Utaiwan Utaipat
- Research Institute for Health Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Yanee Kawilapan
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Chunya Puttikhunt
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10700, Thailand; Dengue Hemorrhagic Fever Research Unit, Office of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Watchara Kasinrerk
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand; Biomedical Technology Research Center, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency at the Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Sutee Yoksan
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Prasert Auewarakul
- Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Prida Malasit
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10700, Thailand; Dengue Hemorrhagic Fever Research Unit, Office of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Nicha Charoensri
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
| | - Nopporn Sittisombut
- Medical Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Bangkok 10700, Thailand; Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
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67
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Veesler D, Kearney BM, Johnson JE. Integration of X-ray crystallography and electron cryo-microscopy in the analysis of virus structure and function. CRYSTALLOGR REV 2015. [DOI: 10.1080/0889311x.2015.1038530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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68
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Complexity of Neutralizing Antibodies against Multiple Dengue Virus Serotypes after Heterotypic Immunization and Secondary Infection Revealed by In-Depth Analysis of Cross-Reactive Antibodies. J Virol 2015; 89:7348-62. [PMID: 25972550 DOI: 10.1128/jvi.00273-15] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED The four serotypes of dengue virus (DENV) cause the most important and rapidly emerging arboviral diseases in humans. The recent phase 2b and 3 studies of a tetravalent dengue vaccine reported a moderate efficacy despite the presence of neutralizing antibodies, highlighting the need for a better understanding of neutralizing antibodies in polyclonal human sera. Certain type-specific (TS) antibodies were recently discovered to account for the monotypic neutralizing activity and protection after primary DENV infection. The nature of neutralizing antibodies after secondary DENV infection remains largely unknown. In this study, we examined sera from 10 vaccinees with well-documented exposure to first and second DENV serotypes through heterotypic immunization with live-attenuated vaccines. Higher serum IgG avidities to both exposed and nonexposed serotypes were found after secondary immunization than after primary immunization. Using a two-step depletion protocol to remove different anti-envelope antibodies, including group-reactive (GR) and complex-reactive (CR) antibodies separately, we found GR and CR antibodies together contributed to more than 50% of neutralizing activities against multiple serotypes after secondary immunization. Similar findings were demonstrated in patients after secondary infection. Anti-envelope antibodies recognizing previously exposed serotypes consisted of a large proportion of GR antibodies, CR antibodies, and a small proportion of TS antibodies, whereas those recognizing nonexposed serotypes consisted of GRand CR antibodies. These findings have implications for sequential heterotypic immunization or primary immunization of DENV-primed individuals as alternative strategies for DENV vaccination. The complexity of neutralizing antibodies after secondary infection provides new insights into the difficulty of their application as surrogates of protection. IMPORTANCE The four serotypes of dengue virus (DENV) are the leading cause of arboviral diseases in humans. Despite the presence of neutralizing antibodies, a moderate efficacy was recently reported in phase 2b and 3 trials of a dengue vaccine; a better understanding of neutralizing antibodies in polyclonal human sera is urgently needed.We studied vaccinees who received heterotypic immunization of live-attenuated vaccines, as they were known to have received the first and second DENV serotype exposures.We found anti-envelope antibodies consist of group-reactive (GR), complex-reactive (CR), and type-specific (TS) antibodies, and that both GR and CR antibodies contribute significantly to multitypic neutralizing activities after secondary DENV immunization. These findings have implications for alternative strategies for DENV vaccination. Certain TS antibodies were recently discovered to contribute to the monotypic neutralizing activity and protection after primary DENV infection; our findings of the complexity of neutralizing activities after secondary immunization/infection provide new insights for neutralizing antibodies as surrogates of protection.
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69
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Temperature dependent conformational change of dengue virus. Curr Opin Virol 2015; 12:109-12. [PMID: 25974180 DOI: 10.1016/j.coviro.2015.04.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/14/2015] [Accepted: 04/17/2015] [Indexed: 11/20/2022]
Abstract
Dengue virus is the causative agent of dengue virus fever. It infects about 400 million people per year and leads to about 21,000 deaths annually. There is available neither a fully successful vaccine nor a successful drug therapy. Some dengue virus serotypes undergo a temperature dependent conformational change from a 'smooth' form at lower temperatures to a 'bumpy' form at temperatures approaching 37°C, the human body temperature. The bumpy structure is less stable and is probably an intermediate in the formation of a fusogenic virus particle.
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70
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Espósito DLA, Nguyen JB, DeWitt DC, Rhoades E, Modis Y. Physico-chemical requirements and kinetics of membrane fusion of flavivirus-like particles. J Gen Virol 2015; 96:1702-11. [PMID: 25740960 PMCID: PMC4635454 DOI: 10.1099/vir.0.000113] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Flaviviruses deliver their RNA genome into the host-cell cytoplasm by fusing their lipid envelope with a cellular membrane. Expression of the flavivirus pre-membrane and envelope glycoprotein genes in the absence of other viral genes results in the spontaneous assembly and secretion of virus-like particles (VLPs) with membrane fusion activity. Here, we examined the physico-chemical requirements for membrane fusion of VLPs from West Nile and Japanese encephalitis viruses. In a bulk fusion assay, optimal hemifusion (or lipid mixing) efficiencies were observed at 37 °C. Fusion efficiency increased with decreasing pH; half-maximal hemifusion was attained at pH 5.6. The anionic lipids bis(monoacylglycero)phosphate and phosphatidylinositol-3-phosphate, when present in the target membrane, significantly enhanced fusion efficiency, consistent with the emerging model that flaviviruses fuse with intermediate-to-late endosomal compartments, where these lipids are most abundant. In a single-particle fusion assay, VLPs catalysed membrane hemifusion, tracked as lipid mixing with the cellular membrane, on a timescale of 7–20 s after acidification. Lipid mixing kinetics suggest that hemifusion is a kinetically complex, multistep process.
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Affiliation(s)
- Danillo L A Espósito
- 1Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - Jennifer B Nguyen
- 1Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - David C DeWitt
- 1Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
| | - Elizabeth Rhoades
- 1Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA 2Department of Physics, Yale University, New Haven, CT 06520, USA
| | - Yorgo Modis
- 1Department of Molecular Biophysics & Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520, USA
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71
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Dejnirattisai W, Wongwiwat W, Supasa S, Zhang X, Dai X, Rouvinski A, Jumnainsong A, Edwards C, Quyen NTH, Duangchinda T, Grimes JM, Tsai WY, Lai CY, Wang WK, Malasit P, Farrar J, Simmons CP, Zhou ZH, Rey FA, Mongkolsapaya J, Screaton GR. A new class of highly potent, broadly neutralizing antibodies isolated from viremic patients infected with dengue virus. Nat Immunol 2015; 16:170-177. [PMID: 25501631 PMCID: PMC4445969 DOI: 10.1038/ni.3058] [Citation(s) in RCA: 361] [Impact Index Per Article: 40.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 11/18/2014] [Indexed: 02/06/2023]
Abstract
Dengue is a rapidly emerging, mosquito-borne viral infection, with an estimated 400 million infections occurring annually. To gain insight into dengue immunity, we characterized 145 human monoclonal antibodies (mAbs) and identified a previously unknown epitope, the envelope dimer epitope (EDE), that bridges two envelope protein subunits that make up the 90 repeating dimers on the mature virion. The mAbs to EDE were broadly reactive across the dengue serocomplex and fully neutralized virus produced in either insect cells or primary human cells, with 50% neutralization in the low picomolar range. Our results provide a path to a subunit vaccine against dengue virus and have implications for the design and monitoring of future vaccine trials in which the induction of antibody to the EDE should be prioritized.
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Affiliation(s)
- Wanwisa Dejnirattisai
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
| | - Wiyada Wongwiwat
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
| | - Sunpetchuda Supasa
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
- Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Xiaokang Zhang
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, Paris, France
- CNRS UMR 3569 Virologie, Paris, France
| | - Xinghong Dai
- Department of Microbiology, Immunology and Molecular Genetics and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Alexander Rouvinski
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, Paris, France
- CNRS UMR 3569 Virologie, Paris, France
| | - Amonrat Jumnainsong
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
- The Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Carolyn Edwards
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
| | - Nguyen Than Ha Quyen
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
| | - Thaneeya Duangchinda
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Jonathan M Grimes
- Division of Structural Biology and Oxford Protein Production Facility, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
- Science Division, Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK
| | - Wen-Yang Tsai
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Chih-Yun Lai
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Wei-Kung Wang
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, USA
| | - Prida Malasit
- Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Jeremy Farrar
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
| | - Cameron P Simmons
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Program, Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam
- Department of Microbiology and Immunology, University of Melbourne, Carlton, Victoria, Australia
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics and California NanoSystems Institute, University of California Los Angeles, Los Angeles, California, USA
| | - Felix A Rey
- Institut Pasteur, Département de Virologie, Unité de Virologie Structurale, Paris, France
- CNRS UMR 3569 Virologie, Paris, France
| | - Juthathip Mongkolsapaya
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
- Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Gavin R Screaton
- Division of Immunology and Inflammation, Department of Medicine, Faculty of Medicine, Hammersmith Campus, Imperial College, London, UK
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Abstract
UNLABELLED Flaviviruses undergo large conformational changes during their life cycle. Under acidic pH conditions, the mature virus forms transient fusogenic trimers of E glycoproteins that engage the lipid membrane in host cells to initiate viral fusion and nucleocapsid penetration into the cytoplasm. However, the dynamic nature of the fusogenic trimer has made the determination of its structure a challenge. Here we have used Fab fragments of the neutralizing antibody DV2-E104 to stop the conformational change of dengue virus at an intermediate stage of the fusion process. Using cryo-electron microscopy, we show that in this intermediate stage, the E glycoproteins form 60 trimers that are similar to the predicted "open" fusogenic trimer. IMPORTANCE The structure of a dengue virus has been captured during the formation of fusogenic trimers. This was accomplished by binding Fab fragments of the neutralizing antibody DV2-E104 to the virus at neutral pH and then decreasing the pH to 5.5. These trimers had an "open" conformation, which is distinct from the "closed" conformation of postfusion trimers. Only two of the three E proteins within each spike are bound by a Fab molecule at domain III. Steric hindrance around the icosahedral 3-fold axes prevents binding of a Fab to the third domain III of each E protein spike. Binding of the DV2-E104 Fab fragments prevents domain III from rotating by about 130° to the postfusion orientation and thus precludes the stem region from "zipping" together the three E proteins along the domain II boundaries into the "closed" postfusion conformation, thus inhibiting fusion.
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73
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Hsieh SC, Wu YC, Zou G, Nerurkar VR, Shi PY, Wang WK. Highly conserved residues in the helical domain of dengue virus type 1 precursor membrane protein are involved in assembly, precursor membrane (prM) protein cleavage, and entry. J Biol Chem 2014; 289:33149-60. [PMID: 25326389 DOI: 10.1074/jbc.m114.610428] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The envelope and precursor membrane (prM) proteins of dengue virus (DENV) are present on the surface of immature virions. During maturation, prM protein is cleaved by furin protease into pr peptide and membrane (M) protein. Although previous studies mainly focusing on the pr region have identified several residues important for DENV replication, the functional role of M protein, particularly the α-helical domain (MH), which is predicted to undergo a large conformational change during maturation, remains largely unknown. In this study, we investigated the role of nine highly conserved MH domain residues in the replication cycle of DENV by site-directed mutagenesis in a DENV1 prME expression construct and found that alanine substitutions introduced to four highly conserved residues at the C terminus and one at the N terminus of the MH domain greatly affect the production of both virus-like particles and replicon particles. Eight of the nine alanine mutants affected the entry of replicon particles, which correlated with the impairment in prM cleavage. Moreover, seven mutants were found to have reduced prM-E interaction at low pH, which may inhibit the formation of smooth immature particles and exposure of prM cleavage site during maturation, thus contributing to inefficient prM cleavage. Taken together, these results are the first report showing that highly conserved MH domain residues, located at 20-38 amino acids downstream from the prM cleavage site, can modulate the prM cleavage, maturation of particles, and virus entry. The highly conserved nature of these residues suggests potential targets of antiviral strategy.
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Affiliation(s)
- Szu-Chia Hsieh
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
| | - Yi-Chieh Wu
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
| | - Gang Zou
- the Wadsworth Center, New York State Department of Health, Albany, New York 12208
| | - Vivek R Nerurkar
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
| | - Pei-Yong Shi
- the Wadsworth Center, New York State Department of Health, Albany, New York 12208
| | - Wei-Kung Wang
- From the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813 and
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Widman DG, Baric RS. Dengue virus envelope protein domain I/II hinge: a key target for dengue virus vaccine design? Expert Rev Vaccines 2014; 14:5-8. [DOI: 10.1586/14760584.2015.961431] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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75
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Merino-Ramos T, Blázquez AB, Escribano-Romero E, Cañas-Arranz R, Sobrino F, Saiz JC, Martín-Acebes MA. Protection of a single dose west nile virus recombinant subviral particle vaccine against lineage 1 or 2 strains and analysis of the cross-reactivity with Usutu virus. PLoS One 2014; 9:e108056. [PMID: 25229345 PMCID: PMC4168257 DOI: 10.1371/journal.pone.0108056] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 08/19/2014] [Indexed: 12/30/2022] Open
Abstract
West Nile virus (WNV) is a neurovirulent mosquito-borne flavivirus. High WNV virulence was mainly associated with lineage 1 strains, but recent outbreaks have unveiled circulation of highly virulent lineage 2 strains. Co-expression of flavivirus prM and E glycoproteins drives the assembly of recombinant subviral particles (RSPs) that share antigenic features with virions. Mouse immunization with lineage 1 WNV RSPs induced a potent humoral response against WNV with production of neutralizing antibodies. A single inoculation of RSPs formulated with Al(OH)3 as adjuvant protected mice against a lethal challenge with WNV strains from lineage 1 or 2. The cross-reactivity of the response elicited by these RSPs was analyzed against the related flavivirus Usutu virus (USUV), which shares multiple ecological and antigenic features with WNV. Immunization with WNV-RSPs increased specific, although low, antibody titers found upon subsequent USUV infection.
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Affiliation(s)
- Teresa Merino-Ramos
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Ana-Belén Blázquez
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Estela Escribano-Romero
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Rodrigo Cañas-Arranz
- Departamento de Virología y Microbiología, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Francisco Sobrino
- Departamento de Virología y Microbiología, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Cantoblanco, Madrid, Spain
- * E-mail: (FS); (JCS)
| | - Juan-Carlos Saiz
- Departamento de Biotecnología, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
- * E-mail: (FS); (JCS)
| | - Miguel A. Martín-Acebes
- Departamento de Virología y Microbiología, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Cantoblanco, Madrid, Spain
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76
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Virus-like particle secretion and genotype-dependent immunogenicity of dengue virus serotype 2 DNA vaccine. J Virol 2014; 88:10813-30. [PMID: 25008922 DOI: 10.1128/jvi.00810-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Dengue virus (DENV), composed of four distinct serotypes, is the most important and rapidly emerging arthropod-borne pathogen and imposes substantial economic and public health burdens. We constructed candidate vaccines containing the DNA of five of the genotypes of dengue virus serotype 2 (DENV-2) and evaluated the immunogenicity, the neutralizing (Nt) activity of the elicited antibodies, and the protective efficacy elicited in mice immunized with the vaccine candidates. We observed a significant correlation between the level of in vitro virus-like particle secretion, the elicited antibody response, and the protective efficacy of the vaccines containing the DNA of the different DENV genotypes in immunized mice. However, higher total IgG antibody levels did not always translate into higher Nt antibodies against homologous and heterologous viruses. We also found that, in contrast to previous reports, more than 50% of total IgG targeted ectodomain III (EDIII) of the E protein, and a substantial fraction of this population was interdomain highly neutralizing flavivirus subgroup-cross-reactive antibodies, such as monoclonal antibody 1B7-5. In addition, the lack of a critical epitope(s) in the Sylvatic genotype virus recognized by interdomain antibodies could be the major cause of the poor protection of mice vaccinated with the Asian 1 genotype vaccine (pVD2-Asian 1) from lethal challenge with virus of the Sylvatic genotype. In conclusion, although the pVD2-Asian 1 vaccine was immunogenic, elicited sufficient titers of Nt antibodies against all DENV-2 genotypes, and provided 100% protection against challenge with virus of the homologous Asian 1 genotype and virus of the heterologous Cosmopolitan genotype, it is critical to monitor the potential emergence of Sylvatic genotype viruses, since vaccine candidates under development may not protect vaccinated humans from these viruses. IMPORTANCE Five genotype-specific dengue virus serotype 2 (DENV-2) DNA vaccine candidates were evaluated for their immunogenicity, homologous and heterologous neutralizing (Nt) antibody titers, and cross-genotype protection in a murine model. The immunity elicited by our prototype vaccine candidate (Asian 1 genotype strain 16681) in mice was protective against viruses of other genotypes but not against virus of the Sylvatic genotype, whose emergence and potential risk after introduction into the human population have previously been demonstrated. The underlying mechanism of a lack of protection elicited by the prototype vaccine may at least be contributed by the absence of a flavivirus subgroup-cross-reactive, highly neutralizing monoclonal antibody 1B7-5-like epitope in DENV-2 of the Sylvatic genotype. The DENV DNA vaccine directs the synthesis and assembly of virus-like particles (VLPs) and induces immune responses similar to those elicited by live-attenuated vaccines, and its flexibility permits the fast deployment of vaccine to combat emerging viruses, such as Sylvatic genotype viruses. The enhanced VLP secretion obtained by replacement of ectodomain I-II (EDI-II) of the Cosmopolitan genotype vaccine construct (VD2-Cosmopolitan) with the Asian 1 EDI-II elicited significantly higher total IgG and Nt antibody titers and suggests a novel approach to enhance the immunogenicity of the DNA vaccine. A DENV vaccine capable of eliciting protective immunity against viruses of existing and emerging genotypes should be the focus of future DENV vaccine development.
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77
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Pierson TC, Diamond MS. Vaccine Development as a Means to Control Dengue Virus Pathogenesis: Do We Know Enough? Annu Rev Virol 2014; 1:375-98. [PMID: 26958727 DOI: 10.1146/annurev-virology-031413-085453] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dengue virus (DENV) is a mosquito-transmitted RNA virus responsible for 390 million infections each year and significant morbidity and mortality throughout tropical and subtropical regions of the world. Efforts to develop a DENV vaccine span 70 years and include the work of luminaries of the virus vaccine field. Although vaccines have been used to reduce the global health burden of other flaviviruses, the unique requirement for a single vaccine to protect against four different groups of dengue viruses, and the link between secondary infections and DENV disease pathogenesis, has limited success to date. In this review, we discuss several promising DENV vaccine candidates in clinical trials and assess how recent advances in understanding of DENV biology and immunity may expedite efforts toward the development of safe and effective vaccines.
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Affiliation(s)
- Theodore C Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892;
| | - Michael S Diamond
- Departments of Medicine, Molecular Microbiology, and Pathology & Immunology, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, Missouri 63110;
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Characterization of the ectodomain of the envelope protein of dengue virus type 4: expression, membrane association, secretion and particle formation in the absence of precursor membrane protein. PLoS One 2014; 9:e100641. [PMID: 24950216 PMCID: PMC4065094 DOI: 10.1371/journal.pone.0100641] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 05/29/2014] [Indexed: 01/08/2023] Open
Abstract
Background The envelope (E) of dengue virus (DENV) is the major target of neutralizing antibodies and vaccine development. After biosynthesis E protein forms a heterodimer with precursor membrane (prM) protein. Recent reports of infection enhancement by anti-prM monoclonal antibodies (mAbs) suggest anti-prM responses could be potentially harmful. Previously, we studied a series of C-terminal truncation constructs expressing DENV type 4 prM/E or E proteins and found the ectodomain of E protein alone could be recognized by all 12 mAbs tested, suggesting E protein ectodomain as a potential subunit immunogen without inducing anti-prM response. The characteristics of DENV E protein ectodomain in the absence of prM protein remains largely unknown. Methodology/Principal Findings In this study, we investigated the expression, membrane association, glycosylation pattern, secretion and particle formation of E protein ectodomain of DENV4 in the presence or absence of prM protein. E protein ectodomain associated with membrane in or beyond trans-Golgi and contained primarily complex glycans, whereas full-length E protein associated with ER membrane and contained high mannose glycans. In the absence of prM protein, E protein ectodomain can secrete as well as form particles of approximately 49 nm in diameter, as revealed by sucrose gradient ultracentrifugation with or without detergent and electron microscopy. Mutational analysis revealed that the secretion of E protein ectodomain was affected by N-linked glycosylation and could be restored by treatment with ammonia chloride. Conclusions/Significance Considering the enhancement of DENV infectivity by anti-prM antibodies, our findings provide new insights into the expression and secretion of E protein ectodomain in the absence of prM protein and contribute to future subunit vaccine design.
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79
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Zheng A, Yuan F, Kleinfelter LM, Kielian M. A toggle switch controls the low pH-triggered rearrangement and maturation of the dengue virus envelope proteins. Nat Commun 2014; 5:3877. [PMID: 24846574 PMCID: PMC4063126 DOI: 10.1038/ncomms4877] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 04/14/2014] [Indexed: 11/09/2022] Open
Abstract
Immature dengue virus particles undergo a dramatic conformational change upon exposure to the acidic environment of the late secretory pathway. The interactions of the E fusion proteins and prM chaperone proteins on the virus envelope are reorganized to permit prM processing by a host protease, furin, thus priming virus for fusion and infection. Here we identify a pH-dependent toggle switch that controls this key conformational change during virus maturation. Our data show that the M region of prM interacts with E at neutral pH but is released at acidic pH, while the pr region interacts with E at acidic pH but is released at neutral pH. Alanine substitution of the conserved residue H98 in prM disrupts the switch by inhibiting dissociation of M from E at low pH, resulting in impaired prM processing and decreased virus infectivity. Thus, release of M-E interaction at low pH promotes formation of a furin-accessible intermediate.
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Affiliation(s)
- Aihua Zheng
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Fei Yuan
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Lara M Kleinfelter
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Margaret Kielian
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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80
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Glutamic acid at residue 125 of the prM helix domain interacts with positively charged amino acids in E protein domain II for Japanese encephalitis virus-like-particle production. J Virol 2014; 88:8386-96. [PMID: 24829339 DOI: 10.1128/jvi.00937-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED Interaction between E and prM proteins in flavivirus-infected cells is a major factor for virus-like particle (VLP) production. The prM helical (prM-H) domain is topologically close to and may interact with domain II of the E protein (EDII). In this study, we investigated prM-H domain amino acid residues facing Japanese encephalitis virus EDII using site-directed mutagenesis to determine their roles in prM-E interaction and VLP production. Our results indicate that negatively charged prM-E125 residue at the prM-H domain affected VLP production via one or more interactions with positively charged E-K93 and E-H246 residues at EDII. Exchanges of oppositely charged residue side chains at prM-E125/E-K93 and prM-E125/E-H246 are recoverable for VLP production. The prM-E125 and E-H246 residues are conserved and that the positive charge of the E-K93 residue is preserved in different flavivirus groups. These findings suggest that the electrostatic attractions of prM-E125, E-K93, and E-H246 residues are important to flavivirus VLP production and that inhibiting these interactions is a potential strategy for blocking flavivirus infections. IMPORTANCE Molecular interaction between E and prM proteins of Japanese encephalitis virus is a major driving force for virus-like particle (VLP) production. The current high-resolution structures available for prM-E complexes do not include the membrane proximal stem region of prM. The prM stem region contains an N-terminal loop and a helix domain (prM-H). Since the prM-H domain is topologically close to domain II of the E protein (EDII), this study was to determine molecular interactions between the prM-H domain and EDII. We found that the molecular interactions between prM-E125 residue and positively charged E-K93 and E-H246 residues at EDII are critical for VLP production. More importantly, the prM-E125 and E-H246 residues are conserved and the positive charge of the E-K93 residue is preserved in different flavivirus groups. Our findings help refine the structure and molecular interactions on the flavivirus surface and reveal a potential strategy for blocking flavivirus infections by inhibiting these electrostatic interactions.
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81
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Leonova GN, Maystrovskaya OS, Kondratov IG, Takashima I, Belikov SI. The nature of replication of tick-borne encephalitis virus strains isolated from residents of the Russian Far East with inapparent and clinical forms of infection. Virus Res 2014; 189:34-42. [PMID: 24747117 DOI: 10.1016/j.virusres.2014.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 04/03/2014] [Accepted: 04/06/2014] [Indexed: 11/30/2022]
Abstract
We describe the biological properties and molecular characteristics of complete genomes of 33 tick-borne encephalitis virus (TBEV) strains that induced different forms of infection, from inapparent to severe focal ones resulting in fatal outcome. Hemagglutinating activity of Oshima-like strains was higher at pH 5.8, while activity of Sofjin- and Senhzang-like strains were higher at pH 6.2 and 6.8, respectively. We determined susceptibility of porcine kidney (PK) cell cultures to these TBEV strains by cytopathic effect (CPE), plaque formation, and size of plaques. The clinical TBEV strains had higher virus titers both in tissue culture infectious dose 50(TCID50) and in plaque-forming unit (PFU) titers and larger plaques than the inapparent strains. A comparison of virus multiplication kinetics by PFU in culture fluid with kinetics of ELISA antigen and hemagglutinin accumulation suggested a different mechanism of interaction between these virus strains and PK cells at the initial stage of cell infection.
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Affiliation(s)
- Galina N Leonova
- Institute of Epidemiology and Microbiology, Siberian Branch of Russian Academy of Medical Sciences, Vladivostok, Russian Federation.
| | - Olga S Maystrovskaya
- Institute of Epidemiology and Microbiology, Siberian Branch of Russian Academy of Medical Sciences, Vladivostok, Russian Federation
| | - Ilya G Kondratov
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russian Federation
| | - Ikuo Takashima
- Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Sergei I Belikov
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russian Federation
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82
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Belikov SI, Kondratov IG, Potapova UV, Leonova GN. The relationship between the structure of the tick-borne encephalitis virus strains and their pathogenic properties. PLoS One 2014; 9:e94946. [PMID: 24740396 PMCID: PMC3989262 DOI: 10.1371/journal.pone.0094946] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 03/20/2014] [Indexed: 12/11/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is transmitted to vertebrates by taiga or forest ticks through bites, inducing disease of variable severity. The reasons underlying these differences in the severity of the disease are unknown. In order to identify genetic factors affecting the pathogenicity of virus strains, we have sequenced and compared the complete genomes of 34 Far-Eastern subtype (FE) TBEV strains isolated from patients with different disease severity (Primorye, the Russian Far East). We analyzed the complete genomes of 11 human pathogenic strains isolated from the brains of dead patients with the encephalitic form of the disease (Efd), 4 strains from the blood of patients with the febrile form of TBE (Ffd), and 19 strains from patients with the subclinical form of TBE (Sfd). On the phylogenetic tree, pathogenic Efd strains formed two clusters containing the prototype strains, Senzhang and Sofjin, respectively. Sfd strains formed a third separate cluster, including the Oshima strain. The strains that caused the febrile form of the disease did not form a separate cluster. In the viral proteins, we found 198 positions with at least one amino acid residue substitution, of which only 17 amino acid residue substitutions were correlated with the variable pathogenicity of these strains in humans and they authentically differed between the groups. We considered the role of each amino acid substitution and assumed that the deletion of 111 amino acids in the capsid protein in combination with the amino acid substitutions R16K and S45F in the NS3 protease may affect the budding process of viral particles. These changes may be the major reason for the diminished pathogenicity of TBEV strains. We recommend Sfd strains for testing as attenuation vaccine candidates.
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MESH Headings
- 3' Untranslated Regions/genetics
- 5' Untranslated Regions/genetics
- Amino Acid Sequence
- Amino Acid Substitution
- Animals
- Base Sequence
- Capsid Proteins/chemistry
- Capsid Proteins/genetics
- China
- Encephalitis Viruses, Tick-Borne/classification
- Encephalitis Viruses, Tick-Borne/genetics
- Encephalitis Viruses, Tick-Borne/pathogenicity
- Encephalitis, Tick-Borne/blood
- Encephalitis, Tick-Borne/virology
- Genetic Structures
- Genome, Viral/genetics
- Geography
- Humans
- Models, Molecular
- Molecular Sequence Data
- Nucleic Acid Conformation
- Phylogeny
- Protein Structure, Tertiary
- RNA Helicases/chemistry
- RNA Helicases/genetics
- RNA, Viral/chemistry
- RNA, Viral/genetics
- Russia
- Sequence Homology, Amino Acid
- Serine Endopeptidases/chemistry
- Serine Endopeptidases/genetics
- Viral Nonstructural Proteins/chemistry
- Viral Nonstructural Proteins/genetics
- Virulence/genetics
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Affiliation(s)
- Sergei I. Belikov
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
| | - Ilya G. Kondratov
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
| | - Ulyana V. Potapova
- Limnological Institute, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
| | - Galina N. Leonova
- Research Institute of Epidemiology and Microbiology, Siberian Branch, Russian Academy of Medical Sciences, Vladivostok, Russia
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83
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Abstract
This review is a partially personal account of the discovery of virus structure and its implication for virus function. Although I have endeavored to cover all aspects of structural virology and to acknowledge relevant individuals, I know that I have favored taking examples from my own experience in telling this story. I am anxious to apologize to all those who I might have unintentionally offended by omitting their work. The first knowledge of virus structure was a result of Stanley's studies of tobacco mosaic virus (TMV) and the subsequent X-ray fiber diffraction analysis by Bernal and Fankuchen in the 1930s. At about the same time it became apparent that crystals of small RNA plant and animal viruses could diffract X-rays, demonstrating that viruses must have distinct and unique structures. More advances were made in the 1950s with the realization by Watson and Crick that viruses might have icosahedral symmetry. With the improvement of experimental and computational techniques in the 1970s, it became possible to determine the three-dimensional, near-atomic resolution structures of some small icosahedral plant and animal RNA viruses. It was a great surprise that the protecting capsids of the first virus structures to be determined had the same architecture. The capsid proteins of these viruses all had a 'jelly-roll' fold and, furthermore, the organization of the capsid protein in the virus were similar, suggesting a common ancestral virus from which many of today's viruses have evolved. By this time a more detailed structure of TMV had also been established, but both the architecture and capsid protein fold were quite different to that of the icosahedral viruses. The small icosahedral RNA virus structures were also informative of how and where cellular receptors, anti-viral compounds, and neutralizing antibodies bound to these viruses. However, larger lipid membrane enveloped viruses did not form sufficiently ordered crystals to obtain good X-ray diffraction. Starting in the 1990s, these enveloped viruses were studied by combining cryo-electron microscopy of the whole virus with X-ray crystallography of their protein components. These structures gave information on virus assembly, virus neutralization by antibodies, and virus fusion with and entry into the host cell. The same techniques were also employed in the study of complex bacteriophages that were too large to crystallize. Nevertheless, there still remained many pleomorphic, highly pathogenic viruses that lacked the icosahedral symmetry and homogeneity that had made the earlier structural investigations possible. Currently some of these viruses are starting to be studied by combining X-ray crystallography with cryo-electron tomography.
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84
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Diagnostic potential and antigenic properties of recombinant tick-borne encephalitis virus subviral particles expressed in mammalian cells from Semliki Forest virus replicons. J Clin Microbiol 2013; 52:814-22. [PMID: 24371235 DOI: 10.1128/jcm.02488-13] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The precursor membrane envelope (prME) proteins of all three tick-borne encephalitis virus (TBEV) subtypes were produced based on expression from Semliki Forest virus (SFV) replicons transcribed from recombinant plasmids. Vero E6 cells transfected by these plasmids showed specific reactivities in immunofluorescence and immunoblot assays by monoclonal antibodies against European and Far-Eastern subtype strains of TBEV, indicating proper folding of the expressed glycoproteins. The prME glycoproteins were secreted into the cell culture supernatant, forming TBEV subviral particles of 20 to 30 nm in diameter. IgM μ-capture and IgG monoclonal antibody (MAb)-capture enzyme immunoassays (EIAs) were developed based on prME Karelia-94 (Siberian subtype) particles. Altogether, 140 human serum samples were tested using these assays, and the results were compared to those obtained with a commercial IgM EIA, an in-house μ-capture IgM assay based on baculovirus-expressed antigen, a commercial IgG EIA, and a hemagglutination inhibition test. Compared to reference enzyme-linked immunosorbent assays (ELISAs), the sensitivities of the generated μ-capture IgM SFV-prME and IgG MAb-capture SFV-prME EIAs were 97.4 to 100% and 98.7%, respectively, and the specificities of the two assays were 100%. IgM and IgG immunofluorescence assays (IFAs) were created based on Vero E6 cells transfected with the recombinant plasmid carrying the TBEV Karelia-94 prME glycoproteins. The IgM IFA was 100% concordant with the μ-capture IgM bac-prME ELISA. The IgG IFA sensitivity and specificity were 98.7% and 100%, respectively, compared to those of the commercial ELISA. In conclusion, the tests developed based on SFV replicon-driven expression of TBEV glycoproteins provide safe and robust alternatives for conducting TBEV serology.
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85
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Nour AM, Li Y, Wolenski J, Modis Y. Viral membrane fusion and nucleocapsid delivery into the cytoplasm are distinct events in some flaviviruses. PLoS Pathog 2013; 9:e1003585. [PMID: 24039574 PMCID: PMC3764215 DOI: 10.1371/journal.ppat.1003585] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 07/12/2013] [Indexed: 12/12/2022] Open
Abstract
Flaviviruses deliver their genome into the cell by fusing the viral lipid membrane to an endosomal membrane. The sequence and kinetics of the steps required for nucleocapsid delivery into the cytoplasm remain unclear. Here we dissect the cell entry pathway of virions and virus-like particles from two flaviviruses using single-particle tracking in live cells, a biochemical membrane fusion assay and virus infectivity assays. We show that the virus particles fuse with a small endosomal compartment in which the nucleocapsid remains trapped for several minutes. Endosomal maturation inhibitors inhibit infectivity but not membrane fusion. We propose a flavivirus cell entry mechanism in which the virus particles fuse preferentially with small endosomal carrier vesicles and depend on back-fusion of the vesicles with the late endosomal membrane to deliver the nucleocapsid into the cytoplasm. Virus entry modulates intracellular calcium release and phosphatidylinositol-3-phosphate kinase signaling. Moreover, the broadly cross-reactive therapeutic antibody scFv11 binds to virus-like particles and inhibits fusion. Many viruses package their genetic material into a lipid envelope. In order to deliver their genome into the host-cell cytoplasm, where it can be replicated, viruses must fuse their envelope with a cellular lipid membrane. This fusion event is therefore a critical step in the entry of an enveloped virus into the cell. In this study, we used various cell biological and biochemical approaches to map precisely the cell entry pathway of two major human pathogens from the flavivirus family, yellow fever virus and Japanese encephalitis virus. We discovered that these viruses co-opt cellular phospholipid signaling to promote the fusion of their envelope with the lipid envelope of small compartments inside the host-cell endosomes. The viral genome remains trapped in these compartments for several minutes until the compartments fuse with the surrounding endosomal membrane. It is this second membrane fusion event that delivers the viral genome into the cytoplasm. We also showed that the antibody fragment scFv11 inhibits the fusion of the viral envelope with small lipid compartments, explaining the therapeutic activity of the scFv11 antibody. Our work identifies new vulnerabilities in the entry pathway of flaviviruses, including the formation of small endosomal compartments and two distinct membrane fusion events involving these compartments.
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Affiliation(s)
- Adel M. Nour
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Yue Li
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Joseph Wolenski
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Yorgo Modis
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
- * E-mail:
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86
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Abstract
Tick-borne encephalitis (TBE) virus is the most important human pathogen transmitted by ticks in Eurasia. Inactivated vaccines are available but require multiple doses and frequent boosters to induce and maintain immunity. Thus far, the goal of developing a safe, live attenuated vaccine effective after a single dose has remained elusive. Here we used a replication-defective (single-cycle) flavivirus platform, RepliVax, to generate a safe, single-dose TBE vaccine. Several RepliVax-TBE candidates attenuated by a deletion in the capsid gene were constructed using different flavivirus backbones containing the envelope genes of TBE virus. RepliVax-TBE based on a West Nile virus backbone (RV-WN/TBE) grew more efficiently in helper cells than candidates based on Langat E5, TBE, and yellow fever 17D backbones, and was found to be highly immunogenic and efficacious in mice. Live chimeric yellow fever 17D/TBE, Dengue 2/TBE, and Langat E5/TBE candidates were also constructed but were found to be underattenuated. RV-WN/TBE was demonstrated to be highly immunogenic in Rhesus macaques after a single dose, inducing a significantly more durable humoral immune response compared with three doses of a licensed, adjuvanted human inactivated vaccine. Its immunogenicity was not significantly affected by preexisting immunity against WN. Immunized monkeys were protected from a stringent surrogate challenge. These results support the identification of a single-cycle TBE vaccine with a superior product profile to existing inactivated vaccines, which could lead to improved vaccine coverage and control of the disease.
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87
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Dengue structure differs at the temperatures of its human and mosquito hosts. Proc Natl Acad Sci U S A 2013; 110:6795-9. [PMID: 23569243 DOI: 10.1073/pnas.1304300110] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report on a conformational transition of dengue virus when changing the temperature from that present in its mosquito vectors to that of its human host. Using cryoelectron microscopy, we show that although the virus has a smooth surface, a diameter of ∼500 Å, and little exposed membrane at room temperature, the virions have a bumpy appearance with a diameter of ∼550 Å and some exposed membrane at 37 °C. The bumpy structure at 37 °C was found to be similar to the previously predicted structure of an intermediate between the smooth mature and fusogenic forms. As humans have a body temperature of 37 °C, the bumpy form of the virus would be the form present in humans. Thus, optimal dengue virus vaccines should induce antibodies that preferentially recognize epitopes exposed on the bumpy form of the virus.
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88
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White LJ, Sariol CA, Mattocks MD, Wahala M P B W, Yingsiwaphat V, Collier ML, Whitley J, Mikkelsen R, Rodriguez IV, Martinez MI, de Silva A, Johnston RE. An alphavirus vector-based tetravalent dengue vaccine induces a rapid and protective immune response in macaques that differs qualitatively from immunity induced by live virus infection. J Virol 2013; 87:3409-24. [PMID: 23302884 PMCID: PMC3592161 DOI: 10.1128/jvi.02298-12] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 01/03/2013] [Indexed: 11/20/2022] Open
Abstract
Despite many years of research, a dengue vaccine is not available, and the more advanced live attenuated vaccine candidate in clinical trials requires multiple immunizations with long interdose periods and provides low protective efficacy. Here, we report important contributions to the development of a second-generation dengue vaccine. First, we demonstrate that a nonpropagating vaccine vector based on Venezuelan equine encephalitis virus replicon particles (VRP) expressing two configurations of dengue virus E antigen (subviral particles [prME] and soluble E dimers [E85]) successfully immunized and protected macaques against dengue virus, while antivector antibodies did not interfere with a booster immunization. Second, compared to prME-VRP, E85-VRP induced neutralizing antibodies faster, to higher titers, and with improved protective efficacy. Third, this study is the first to map antigenic domains and specificities targeted by vaccination versus natural infection, revealing that, unlike prME-VRP and live virus, E85-VRP induced only serotype-specific antibodies, which predominantly targeted EDIII, suggesting a protective mechanism different from that induced by live virus and possibly live attenuated vaccines. Fourth, a tetravalent E85-VRP dengue vaccine induced a simultaneous and protective response to all 4 serotypes after 2 doses given 6 weeks apart. Balanced responses and protection in macaques provided further support for exploring the immunogenicity and safety of this vaccine candidate in humans.
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Affiliation(s)
- Laura J White
- Global Vaccines Inc., Research Triangle Park, NC, USA.
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89
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Mutations in the West Nile prM protein affect VLP and virion secretion in vitro. Virology 2012; 433:35-44. [PMID: 22858174 DOI: 10.1016/j.virol.2012.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 05/25/2012] [Accepted: 07/13/2012] [Indexed: 12/22/2022]
Abstract
Mutation of the West Nile virus-like particle (WN VLP) prM protein (T20D, K31A, K31V, or K31T) results in undetectable VLP secretion from transformed COS-1 cells. K31 mutants formed intracellular prM-E heterodimers; however these proteins remained in the ER and ER-Golgi intermediary compartments of transfected cells. The T20D mutation affected glycosylation, heterodimer formation, and WN VLP secretion. When infectious viruses bearing the same mutations were used to infect COS-1 cells, K31 mutant viruses exhibited delayed growth and reduced infectivity compared to WT virus. Epitope maps of WN VLP and WNV prM were also different. These results suggest that while mutations in the prM protein can reduce or eliminate secretion of WN VLPs, they have less effect on virus. This difference may be due to the quantity of prM in WN VLPs compared to WNV or to differences in maturation, structure, and symmetry of these particles.
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90
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Chiou SS, Fan YC, Crill WD, Chang RY, Chang GJJ. Mutation analysis of the cross-reactive epitopes of Japanese encephalitis virus envelope glycoprotein. J Gen Virol 2012; 93:1185-1192. [DOI: 10.1099/vir.0.040238-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Group and serocomplex cross-reactive epitopes have been identified in the envelope (E) protein of several flaviviruses and have proven critical in vaccine and diagnostic antigen development. Here, we performed site-directed mutagenesis across the E gene of a recombinant expression plasmid that encodes the Japanese encephalitis virus (JEV) premembrane (prM) and E proteins and produces JEV virus-like particles (VLPs). Mutations were introduced at I135 and E138 in domain I; W101, G104, G106 and L107 in domain II; and T305, E306, K312, A315, S329, S331, G332 and D389 in domain III. None of the mutant JEV VLPs demonstrated reduced activity to the five JEV type-specific mAbs tested. Substitutions at W101, especially W101G, reduced reactivity dramatically with all of the flavivirus group cross-reactive mAbs. The group and JEV serocomplex cross-reactive mAbs examined recognized five and six different overlapping epitopes, respectively. Among five group cross-reactive epitopes, amino acids located in domains I, II and III were involved in one, five and three epitopes, respectively. Recognition by six JEV serocomplex cross-reactive mAbs was reduced by amino acid substitutions in domains II and III. These results suggest that amino acid residues located in the fusion loop of E domain II are the most critical for recognition by group cross-reactive mAbs, followed by residues of domains III and I. The amino acid residues of both domains II and III of the E protein were shown to be important in the binding of JEV serocomplex cross-reactive mAbs.
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Affiliation(s)
- Shyan-Song Chiou
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Yi-Chin Fan
- Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Wayne D. Crill
- Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, USA
| | - Ruey-Yi Chang
- Institute of Biotechnology and Department of Life Science, National Dong Hwa University, Hualien, Taiwan, ROC
| | - Gwong-Jen J. Chang
- Arboviral Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, USA
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91
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Schmidt AG, Lee K, Yang PL, Harrison SC. Small-molecule inhibitors of dengue-virus entry. PLoS Pathog 2012; 8:e1002627. [PMID: 22496653 PMCID: PMC3320583 DOI: 10.1371/journal.ppat.1002627] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 02/22/2012] [Indexed: 01/28/2023] Open
Abstract
Flavivirus envelope protein (E) mediates membrane fusion and viral entry from endosomes. A low-pH induced, dimer-to-trimer rearrangement and reconfiguration of the membrane-proximal “stem" of the E ectodomain draw together the viral and cellular membranes. We found stem-derived peptides from dengue virus (DV) bind stem-less E trimer and mimic the stem-reconfiguration step in the fusion pathway. We adapted this experiment as a high-throughput screen for small molecules that block peptide binding and thus may inhibit viral entry. A compound identified in this screen, 1662G07, and a number of its analogs reversibly inhibit DV infectivity. They do so by binding the prefusion, dimeric E on the virion surface, before adsorption to a cell. They also block viral fusion with liposomes. Structure-activity relationship studies have led to analogs with submicromolar IC90s against DV2, and certain analogs are active against DV serotypes 1,2, and 4. The compounds do not inhibit the closely related Kunjin virus. We propose that they bind in a previously identified, E-protein pocket, exposed on the virion surface and although this pocket is closed in the postfusion trimer, its mouth is fully accessible. Examination of the E-trimer coordinates (PDB 1OK8) shows that conformational fluctuations around the hinge could open the pocket without dissociating the trimer or otherwise generating molecular collisions. We propose that compounds such as 1662G07 trap the sE trimer in a “pocket-open" state, which has lost affinity for the stem peptide and cannot support the final “zipping up" of the stem. Fusion of viral and cellular membranes is necessary to establish infection by an enveloped virus. This process is facilitated by rearrangement of protein(s) present on the virion surface in response to molecular cues from the compartment from which fusion occurs, such as low pH of an endosome. Dengue virus is an enveloped virus in the flavivirus family; its “E" (for envelope) protein is the fusion mediator. We previously showed that peptides derived from the membrane proximal “stem" of the E protein bind a form of E that represents a late-stage fusion intermediate. We used this assay to screen for small-molecule inhibitors that compete for stem-peptide association with E. We describe one such inhibitor and its analogs that block viral fusion. These inhibitors also block infectivity if added to dengue virus before infection. Withdrawing the inhibitor before fusion reverses the blockage. We propose that these small molecules bind a hydrophobic pocket on the virion surface and that the virus carries them into the endosome, where they prevent viral fusion by stabilizing an intermediate conformation of the E protein that cannot complete the fusion-promoting conformational change. Identification of these fusion inhibitors shows that viral entry is a possible target for anti-flavivirus drugs.
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Affiliation(s)
- Aaron G. Schmidt
- Jack and Eileen Connors Laboratory of Structural Biology, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kyungae Lee
- New England Regional Center of Excellence in Biodefense and Emerging Infectious Diseases (NERCE/BEID), Harvard Medical School, Boston, Massachusetts, United States of America
| | - Priscilla L. Yang
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Stephen C. Harrison
- Jack and Eileen Connors Laboratory of Structural Biology, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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92
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Lin HE, Tsai WY, Liu IJ, Li PC, Liao MY, Tsai JJ, Wu YC, Lai CY, Lu CH, Huang JH, Chang GJ, Wu HC, Wang WK. Analysis of epitopes on dengue virus envelope protein recognized by monoclonal antibodies and polyclonal human sera by a high throughput assay. PLoS Negl Trop Dis 2012; 6:e1447. [PMID: 22235356 PMCID: PMC3250511 DOI: 10.1371/journal.pntd.0001447] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 11/07/2011] [Indexed: 11/21/2022] Open
Abstract
Background The envelope (E) protein of dengue virus (DENV) is the major target of neutralizing antibodies and vaccine development. While previous studies on domain III or domain I/II alone have reported several epitopes of monoclonal antibodies (mAbs) against DENV E protein, the possibility of interdomain epitopes and the relationship between epitopes and neutralizing potency remain largely unexplored. Methodology/Principal Findings We developed a dot blot assay by using 67 alanine mutants of predicted surface-exposed E residues as a systematic approach to identify epitopes recognized by mAbs and polyclonal sera, and confirmed our findings using a capture-ELISA assay. Of the 12 mouse mAbs tested, three recognized a novel epitope involving residues (Q211, D215, P217) at the central interface of domain II, and three recognized residues at both domain III and the lateral ridge of domain II, suggesting a more frequent presence of interdomain epitopes than previously appreciated. Compared with mAbs generated by traditional protocols, the potent neutralizing mAbs generated by a new protocol recognized multiple residues in A strand or residues in C strand/CC′ loop of DENV2 and DENV1, and multiple residues in BC loop and residues in DE loop, EF loop/F strand or G strand of DENV1. The predominant epitopes of anti-E antibodies in polyclonal sera were found to include both fusion loop and non-fusion residues in the same or adjacent monomer. Conclusions/Significance Our analyses have implications for epitope-specific diagnostics and epitope-based dengue vaccines. This high throughput method has tremendous application for mapping both intra and interdomain epitopes recognized by human mAbs and polyclonal sera, which would further our understanding of humoral immune responses to DENV at the epitope level. Dengue virus is the leading cause of arboviral diseases worldwide. The envelope protein is the major target of neutralizing antibodies and vaccine development. While previous studies have reported several epitopes on envelope protein, the possibility of interdomain epitopes and the relationship of epitopes to neutralizing potency remain unexplored. We developed a high throughput dot blot assay by using 67 alanine mutants of surface-exposed envelope residues as a systematic approach to identify epitopes recognized by mouse monoclonal antibodies and polyclonal human sera. Our results suggested the presence of interdomain epitopes more frequent than previously appreciated. Compared with monoclonal antibodies generated by traditional protocol, the potent neutralizing monoclonal antibodies generated by a new protocol showed several unique features of their epitopes. Moreover, the predominant epitopes of antibodies against envelope protein in polyclonal sera can be identified by this assay. These findings have implications for future development of epitope-specific diagnostics and epitope-based dengue vaccine, and add to our understanding of humoral immune responses to dengue virus at the epitope level.
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Affiliation(s)
- Hong-En Lin
- Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wen-Yang Tsai
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - I-Ju Liu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Pi-Chun Li
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Mei-Ying Liao
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Jih-Jin Tsai
- Tropical Medicine Center and Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
- Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Chieh Wu
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Chih-Yun Lai
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
| | - Chih-Hsuan Lu
- Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Jyh-Hsiung Huang
- Department of Health, Center for Disease Control, Taipei, Taiwan
| | - Gwong-Jen Chang
- Division of Vector-Borne Diseases, Department of Health and Human Service, Center for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Han-Chung Wu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Wei-Kung Wang
- Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii, United States of America
- * E-mail:
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93
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Abstract
Family Flaviviridae genus flavivirus contains numerous pathogenic viruses such as Japanese encephalitis virus, dengue virus, West Nile virus, etc, which cause public health problems in the world. Since many mammals and birds can act as amplifying hosts and reservoir hosts in nature and those viruses are transmitted by haematophagous mosquitoes or ticks, those viruses could not be eradicated from the nature. In the recent few decades, the viral replication mechanism and the ultrastructure of viral proteins as well as the viral immune evasion mechanism have been elucidated extensively, leading to develop novel types of antivirals and vaccines. In this review, the flavivirus nature and epidemiology, replication mechanism, immune response and immune evasion, and antivirals and vaccines against flaviviruses were described.
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Affiliation(s)
- Tomohiro Ishikawa
- Department of Microbiology, Dokkyo Medical University School of Medicine.
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94
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Kudelko M, Brault JB, Kwok K, Li MY, Pardigon N, Peiris JSM, Bruzzone R, Desprès P, Nal B, Wang PG. Class II ADP-ribosylation factors are required for efficient secretion of dengue viruses. J Biol Chem 2011; 287:767-777. [PMID: 22105072 DOI: 10.1074/jbc.m111.270579] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Identification and characterization of virus-host interactions are very important steps toward a better understanding of the molecular mechanisms responsible for disease progression and pathogenesis. To date, very few cellular factors involved in the life cycle of flaviviruses, which are important human pathogens, have been described. In this study, we demonstrate a crucial role for class II Arf proteins (Arf4 and Arf5) in the dengue flavivirus life cycle. We show that simultaneous depletion of Arf4 and Arf5 blocks recombinant subviral particle secretion for all four dengue serotypes. Immunostaining analysis suggests that class II Arf proteins are required at an early pre-Golgi step for dengue virus secretion. Using a horseradish peroxidase protein fused to a signal peptide, we show that class II Arfs act specifically on dengue virus secretion without altering the secretion of proteins through the constitutive secretory pathway. Co-immunoprecipitation data demonstrate that the dengue prM glycoprotein interacts with class II Arf proteins but not through its C-terminal VXPX motif. Finally, experiments performed with replication-competent dengue and yellow fever viruses demonstrate that the depletion of class II Arfs inhibits virus secretion, thus confirming their implication in the virus life cycle, although data obtained with West Nile virus pointed out the differences in virus-host interactions among flaviviruses. Our findings shed new light on a molecular mechanism used by dengue viruses during the late stages of the life cycle and demonstrate a novel function for class II Arf proteins.
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Affiliation(s)
- Mateusz Kudelko
- HKU-Pasteur Research Centre, University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Jean-Baptiste Brault
- Unité des Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, 75724, France
| | - Kevin Kwok
- HKU-Pasteur Research Centre, University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Ming Yuan Li
- HKU-Pasteur Research Centre, University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Nathalie Pardigon
- Unité des Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, 75724, France
| | - J S Malik Peiris
- HKU-Pasteur Research Centre, University of Hong Kong, Hong Kong Special Administrative Region, China; Department of Microbiology, University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Roberto Bruzzone
- HKU-Pasteur Research Centre, University of Hong Kong, Hong Kong Special Administrative Region, China; Department of Cell Biology and Infection, Institut Pasteur, 75724 Paris, France
| | - Philippe Desprès
- Unité des Interactions Moléculaires Flavivirus-Hôtes, Institut Pasteur, Paris, 75724, France
| | - Béatrice Nal
- HKU-Pasteur Research Centre, University of Hong Kong, Hong Kong Special Administrative Region, China; Department of Anatomy, University of Hong Kong, Hong Kong Special Administrative Region, China; Division of Biosciences, School of Health Sciences and Social Care, Brunel University, UB8 3PH London, United Kingdom.
| | - Pei Gang Wang
- HKU-Pasteur Research Centre, University of Hong Kong, Hong Kong Special Administrative Region, China.
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95
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The helical domains of the stem region of dengue virus envelope protein are involved in both virus assembly and entry. J Virol 2011; 85:5159-71. [PMID: 21367896 DOI: 10.1128/jvi.02099-10] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The envelope (E) of dengue virus (DENV) is a determinant of tropism and virulence. At the C terminus of E protein, there is a stem region containing two amphipathic α-helical domains (EH1 and EH2) and a stretch of conserved sequences in between. The crystal structure of E protein at the postfusion state suggested the involvement of the stem during the fusion; however, the critical domains or residues involved remain unknown. Site-directed mutagenesis was carried out to replace each of the stem residues at the hydrophobic face with an alanine or proline in a DENV serotype 4 (DENV4) precursor membrane (prM)/E expression construct. Most of the 15 proline mutations at either EH1 or EH2 severely affected the assembly of virus-like particles (VLPs). Radioimmunoprecipitation and membrane flotation assays revealed that EH1 mutations primarily affect prM-E heterodimerization and EH2 mutations affect the membrane binding of the stem. Introducing four proline mutations at either EH1 or EH2 into a DENV2 replicon packaging system greatly affects assembly and entry. Moreover, introducing these mutations into a DENV2 infectious clone confirmed the impairment in assembly and infectivity. Sequencing analysis of adaptive mutations in passage 5 viruses revealed a change to a leucine or wild-type residue at the original site, suggesting the importance of maintaining the helical structure. Collectively, these findings suggest that the EH1 and EH2 domains are involved in both assembly and entry steps of the DENV replication cycle; this feature, together with the high degree of sequence conservation, suggests that the stem region is a potential target of antiviral strategies.
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96
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The unique transmembrane hairpin of flavivirus fusion protein E is essential for membrane fusion. J Virol 2011; 85:4377-85. [PMID: 21325407 DOI: 10.1128/jvi.02458-10] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The fusion of enveloped viruses with cellular membranes is mediated by proteins that are anchored in the lipid bilayer of the virus and capable of triggered conformational changes necessary for driving fusion. The flavivirus envelope protein E is the only known viral fusion protein with a double membrane anchor, consisting of two antiparallel transmembrane helices (TM1 and TM2). TM1 functions as a stop-transfer sequence and TM2 as an internal signal sequence for the first nonstructural protein during polyprotein processing. The possible role of this peculiar C-terminal helical hairpin in membrane fusion has not been investigated so far. We addressed this question by studying TM mutants of tick-borne encephalitis virus (TBEV) recombinant subviral particles (RSPs), an established model system for flavivirus membrane fusion. The engineered mutations included the deletion of TM2, the replacement of both TM domains (TMDs) by those of the related Japanese encephalitis virus (JEV), and the use of chimeric TBEV-JEV membrane anchors. Using these mutant RSPs, we provide evidence that TM2 is not just a remnant of polyprotein processing but, together with TM1, plays an active role in fusion. None of the TM mutations, including the deletion of TM2, affected early steps of the fusion process, but TM interactions apparently contribute to the stability of the postfusion E trimer and the completion of the merger of the membranes. Our data provide evidence for both intratrimer and intertrimer interactions mediated by the TMDs of E and thus extend the existing models of flavivirus membrane fusion.
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97
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Hsieh SC, Zou G, Tsai WY, Qing M, Chang GJ, Shi PY, Wang WK. The C-terminal helical domain of dengue virus precursor membrane protein is involved in virus assembly and entry. Virology 2010; 410:170-80. [PMID: 21129763 DOI: 10.1016/j.virol.2010.11.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 09/04/2010] [Accepted: 11/06/2010] [Indexed: 11/15/2022]
Abstract
The role of the α-helical domain (MH) of dengue virus (DENV) precursor membrane protein in replication was investigated by site-directed mutagenesis. Proline substitutions of three residues (120, 123 and 127) at the C-terminus, but not those at the N-terminus of MH domain, reduced the virus-like particles of DENV1, DENV2 and DENV4 detected in supernatants. In a DENV2 replicon trans-packaging system, these three mutations suppressed particles detected; two of them (I123P and V127P) also affected viral entry. In the context of DENV2 genome-length RNA, all three mutations reduced virion assembly and virus spreading in cell culture. Analysis of revertants showed that mutation A120P could partially support viral infection cycle; in contrast, mutations I123P and V127P were lethal, and adaptations of I123P→I123L and V127P→V127L were required to restore the viral infection cycle. These findings demonstrate that the C-terminus of the MH domain is involved in both assembly and entry of DENV.
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Affiliation(s)
- Szu-Chia Hsieh
- Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
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98
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Neutralization of West Nile virus by cross-linking of its surface proteins with Fab fragments of the human monoclonal antibody CR4354. Proc Natl Acad Sci U S A 2010; 107:18950-5. [PMID: 20956322 PMCID: PMC2973864 DOI: 10.1073/pnas.1011036107] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Many flaviviruses are significant human pathogens, with the humoral immune response playing an essential role in restricting infection and disease. CR4354, a human monoclonal antibody isolated from a patient, neutralizes West Nile virus (WNV) infection at a postattachment stage in the viral life-cycle. Here, we determined the structure of WNV complexed with Fab fragments of CR4354 using cryoelectron microscopy. The outer glycoprotein shell of a mature WNV particle is formed by 30 rafts of three homodimers of the viral surface protein E. CR4354 binds to a discontinuous epitope formed by protein segments from two neighboring E molecules, but does not cause any detectable structural disturbance on the viral surface. The epitope occurs at two independent positions within an icosahedral asymmetric unit, resulting in 120 binding sites on the viral surface. The cross-linking of the six E monomers within one raft by four CR4354 Fab fragments suggests that the antibody neutralizes WNV by blocking the pH-induced rearrangement of the E protein required for virus fusion with the endosomal membrane.
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99
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Vieyres G, Thomas X, Descamps V, Duverlie G, Patel AH, Dubuisson J. Characterization of the envelope glycoproteins associated with infectious hepatitis C virus. J Virol 2010; 84:10159-68. [PMID: 20668082 PMCID: PMC2937754 DOI: 10.1128/jvi.01180-10] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 07/16/2010] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C is caused by an enveloped virus whose entry is mediated by two glycoproteins, namely, E1 and E2, which have been shown to assemble as a noncovalent heterodimer. Despite extensive research in the field of such an important human pathogen, hepatitis C virus (HCV) glycoproteins have only been studied so far in heterologous expression systems, and their organization at the surfaces of infectious virions has not yet been described. Here, we characterized the envelope glycoproteins associated with cell-cultured infectious virions and compared them with their prebudding counterparts. Viral particles were analyzed by ultracentrifugation, and the envelope glycoproteins were characterized by coimmunoprecipitation and receptor pulldown assays. Furthermore, their oligomeric state was determined by sedimentation through sucrose gradients and by separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions. In sucrose gradient analyses, HCV envelope glycoproteins were associated with fractions containing the most infectious viral particles. Importantly, besides maturation of some of their glycans, HCV envelope glycoproteins showed a dramatic change in their oligomeric state after incorporation into the viral particle. Indeed, virion-associated E1 and E2 envelope glycoproteins formed large covalent complexes stabilized by disulfide bridges, whereas the intracellular forms of these proteins assembled as noncovalent heterodimers. Furthermore, the virion-associated glycoprotein complexes were recognized by the large extracellular loop of CD81 as well as conformation-sensitive antibodies, indicating that these proteins are in a functional conformation. Overall, our study fills a gap in the description of HCV outer morphology and should guide further investigations into virus entry and assembly.
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Affiliation(s)
- Gabrielle Vieyres
- Institut Pasteur de Lille, Center for Infection & Immunity of Lille (CIIL), F-59019 Lille, France; Inserm U1019, F-59019 Lille, France; CNRS UMR8204, F-59021 Lille, France; and Université Lille Nord de France, F-59000 Lille, France, Unité de Virologie Clinique, EA4294 Université de Picardie Jules Verne, Centre Hospitalier Universitaire d'Amiens, Amiens, France, the Medical Research Council—University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Xavier Thomas
- Institut Pasteur de Lille, Center for Infection & Immunity of Lille (CIIL), F-59019 Lille, France; Inserm U1019, F-59019 Lille, France; CNRS UMR8204, F-59021 Lille, France; and Université Lille Nord de France, F-59000 Lille, France, Unité de Virologie Clinique, EA4294 Université de Picardie Jules Verne, Centre Hospitalier Universitaire d'Amiens, Amiens, France, the Medical Research Council—University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Véronique Descamps
- Institut Pasteur de Lille, Center for Infection & Immunity of Lille (CIIL), F-59019 Lille, France; Inserm U1019, F-59019 Lille, France; CNRS UMR8204, F-59021 Lille, France; and Université Lille Nord de France, F-59000 Lille, France, Unité de Virologie Clinique, EA4294 Université de Picardie Jules Verne, Centre Hospitalier Universitaire d'Amiens, Amiens, France, the Medical Research Council—University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Gilles Duverlie
- Institut Pasteur de Lille, Center for Infection & Immunity of Lille (CIIL), F-59019 Lille, France; Inserm U1019, F-59019 Lille, France; CNRS UMR8204, F-59021 Lille, France; and Université Lille Nord de France, F-59000 Lille, France, Unité de Virologie Clinique, EA4294 Université de Picardie Jules Verne, Centre Hospitalier Universitaire d'Amiens, Amiens, France, the Medical Research Council—University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Arvind H. Patel
- Institut Pasteur de Lille, Center for Infection & Immunity of Lille (CIIL), F-59019 Lille, France; Inserm U1019, F-59019 Lille, France; CNRS UMR8204, F-59021 Lille, France; and Université Lille Nord de France, F-59000 Lille, France, Unité de Virologie Clinique, EA4294 Université de Picardie Jules Verne, Centre Hospitalier Universitaire d'Amiens, Amiens, France, the Medical Research Council—University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Jean Dubuisson
- Institut Pasteur de Lille, Center for Infection & Immunity of Lille (CIIL), F-59019 Lille, France; Inserm U1019, F-59019 Lille, France; CNRS UMR8204, F-59021 Lille, France; and Université Lille Nord de France, F-59000 Lille, France, Unité de Virologie Clinique, EA4294 Université de Picardie Jules Verne, Centre Hospitalier Universitaire d'Amiens, Amiens, France, the Medical Research Council—University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
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Ohtaki N, Takahashi H, Kaneko K, Gomi Y, Ishikawa T, Higashi Y, Kurata T, Sata T, Kojima A. Immunogenicity and efficacy of two types of West Nile virus-like particles different in size and maturation as a second-generation vaccine candidate. Vaccine 2010; 28:6588-96. [DOI: 10.1016/j.vaccine.2010.07.055] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 06/14/2010] [Accepted: 07/18/2010] [Indexed: 11/16/2022]
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