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He Y, Zhong L, Yan H, Virata ML, Deng L, Mishra AK, Struble E, Scott D, Zhang P. In vitro enhancement of Zika virus infection by preexisting West Nile virus antibodies in human plasma-derived immunoglobulins revealed after P2 binding site-specific enrichment. Microbiol Spectr 2024; 12:e0075824. [PMID: 38687079 DOI: 10.1128/spectrum.00758-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 04/14/2024] [Indexed: 05/02/2024] Open
Abstract
Human immunoglobulin preparations contain a diverse range of polyclonal antibodies that reflect past immune responses against pathogens encountered by the blood donor population. In this study, we examined a panel of intravenous immunoglobulins (IGIVs) manufactured over the past two decades (1998-2020) for their capacity to neutralize or enhance Zika virus (ZIKV) infection in vitro. These IGIVs were selected specifically based on their production dates in relation to the occurrences of two flavivirus outbreaks in the U.S.: the West Nile virus (WNV) outbreak in 1999 and the ZIKV outbreak in 2015. As demonstrated by enzyme-linked immunosorbent assay (ELISA) experiments, IGIVs made before the ZIKV outbreak already harbored antibodies that bind to various peptides across the envelope protein of ZIKV because of the WNV outbreak. Using phage display, the most dominant binding site was mapped precisely to the P2 peptide between residues 211 and 230 within domain II, where BF1176-56, an anti-ZIKV monoclonal antibody, also binds. When tested in permissive Vero E6 cells for ZIKV neutralization, the IGIVs, even after undergoing rigorous enrichment for P2 binding specificity, failed, as did BF1176-56. Meanwhile, BF1176-56 enhanced ZIKV infection in both FcγRII-expressing K562 cells and human peripheral blood mononuclear cells. However, for enhancement by the IGIVs to be detected in these cells, a substantial increase in their P2 binding specificity was required, thus linking the P2 site with ZIKV enhancement in vitro. Our findings warrant further study of the significance of elevated levels of anti-WNV antibodies in IGIVs, considering that various mechanisms operating in vivo may modulate ZIKV infection outcomes.IMPORTANCEWe investigated the capacity of intravenous immunoglobulins manufactured previously over two decades (1998-2020) to neutralize or enhance Zika virus infection in vitro. West Nile virus antibodies in IGIVs could not neutralize Zika virus initially; however, once the IGIVs were concentrated further, they enhanced its infection. These findings lay the groundwork for exploring how preexisting WNV antibodies in IGIVs could impact Zika infection, both in vitro and in vivo. Our observations are historically significant, since we tested a panel of IGIV lots that were carefully selected based on their production dates which covered two major flavivirus outbreaks in the U.S.: the WNV outbreak in 1999 and the ZIKV outbreak in 2015. These findings will facilitate our understanding of the interplay among closely related viral pathogens, particularly from a historical perspective regarding large blood donor populations. They should remain relevant for future outbreaks of emerging flaviviruses that may potentially affect vulnerable populations.
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Affiliation(s)
- Yong He
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Lilin Zhong
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Hailing Yan
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Maria Luisa Virata
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Lu Deng
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Ashish K Mishra
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Evi Struble
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Dorothy Scott
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
| | - Pei Zhang
- Division of Plasma Derivatives, Office of Plasma Protein Therapeutics CMC, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, Maryland, USA
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Hegazy GE, Abu-Serie MM, Abou-Elela GM, Ghozlan H, Sabry SA, Soliman NA, Teleb M, Abdel-Fattah YR. Bioprocess development for biosurfactant production by Natrialba sp. M6 with effective direct virucidal and anti-replicative potential against HCV and HSV. Sci Rep 2022; 12:16577. [PMID: 36195643 PMCID: PMC9531635 DOI: 10.1038/s41598-022-20091-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 09/08/2022] [Indexed: 11/09/2022] Open
Abstract
Halophilic archaea is considered an promising natural source of many important metabolites. This study focused on one of the surface-active biomolecules named biosurfactants produced by haloarchaeon Natrialba sp. M6. The production trend was optimized and the product was partially purified and identified using GC-Mass spectrometry. Sequential optimization approaches, Plackett-Burman (PB) and Box-Behnken Designs (BBD) were applied to maximize the biosurfactants production from M6 strain by using 14 factors; pH, NaCl, agitation and glycerol; the most significant factors that influenced the biosurfactant production were used for Response Surface Methodology (RSM). The final optimal production conditions were agitation (150 rpm), glycerol (3%), NaCl (20.8%), pH (12) and cultivation temperature (37°C). GC-Mass spectrometry for the recovered extract revealed the presence of a diverse group of bipolar nature, hydrophobic hydrocarbon chain and charged function group. The majority of these compounds are fatty acids. Based on results of GC-MS, compositional analysis content and Zetasizer, it was proposed that the extracted biosurfactant produced by haloarchaeon Natrialba sp. M6 could be a cationic lipoprotein. The antiviral activity of such biosurfactant was investigated against hepatitis C (HCV) and herpes simplex (HSV1) viruses at its maximum safe doses (20 μg/mL and 8 μg/mL, respectively). Its mode of antiviral action was declared to be primarily via deactivating viral envelopes thus preventing viral entry. Moreover, this biosurfactant inhibited RNA polymerase- and DNA polymerase-mediated viral replication at IC50 of 2.28 and 4.39 μg/mL, respectively also. Molecular docking studies showed that surfactin resided well and was bound to the specified motif with low and accepted binding energies (ΔG = - 5.629, - 6.997 kcal/mol) respectively. Therefore, such biosurfactant could be presented as a natural safe and effective novel antiviral agent.
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Affiliation(s)
- Ghada E Hegazy
- National Institute of Oceanography & Fisheries, NIOF-Egypt, Qaitbay Sq, El-Anfousy, Alexandria, 11865, Egypt.
| | - Marwa M Abu-Serie
- Medical Biotechnology Department, Genetic Engineering & Biotechnology Research Institute (GEBRI), City of Scientific Research & Technological Applications, Alexandria, Egypt
| | - G M Abou-Elela
- National Institute of Oceanography & Fisheries, NIOF-Egypt, Qaitbay Sq, El-Anfousy, Alexandria, 11865, Egypt
| | - Hanan Ghozlan
- Botany & Microbiology Department, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Soraya A Sabry
- Botany & Microbiology Department, Faculty of Science, Alexandria University, Alexandria, Egypt
| | - Nadia A Soliman
- Bioprocess Development Department, Genetic Engineering & Biotechnology Research Institute (GEBRI), City of Scientific Research & Technological Applications, New Borg El-Arab City, Universities & Research Institutes Zone, Alexandria, 21934, Egypt
| | - Mohamed Teleb
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Yasser R Abdel-Fattah
- Bioprocess Development Department, Genetic Engineering & Biotechnology Research Institute (GEBRI), City of Scientific Research & Technological Applications, New Borg El-Arab City, Universities & Research Institutes Zone, Alexandria, 21934, Egypt.
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Structural insights into hepatitis C virus receptor binding and entry. Nature 2021; 598:521-525. [PMID: 34526719 PMCID: PMC8542614 DOI: 10.1038/s41586-021-03913-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/13/2021] [Indexed: 02/08/2023]
Abstract
Hepatitis C virus (HCV) infection is a causal agent of chronic liver disease, cirrhosis and hepatocellular carcinoma in humans, and afflicts more than 70 million people worldwide. The HCV envelope glycoproteins E1 and E2 are responsible for the binding of the virus to the host cell, but the exact entry process remains undetermined1. The majority of broadly neutralizing antibodies block interaction between HCV E2 and the large extracellular loop (LEL) of the cellular receptor CD81 (CD81-LEL)2. Here we show that low pH enhances the binding of CD81-LEL to E2, and we determine the crystal structure of E2 in complex with an antigen-binding fragment (2A12) and CD81-LEL (E2-2A12-CD81-LEL); E2 in complex with 2A12 (E2-2A12); and CD81-LEL alone. After binding CD81, residues 418-422 in E2 are displaced, which allows for the extension of an internal loop consisting of residues 520-539. Docking of the E2-CD81-LEL complex onto a membrane-embedded, full-length CD81 places the residues Tyr529 and Trp531 of E2 proximal to the membrane. Liposome flotation assays show that low pH and CD81-LEL increase the interaction of E2 with membranes, whereas structure-based mutants of Tyr529, Trp531 and Ile422 in the amino terminus of E2 abolish membrane binding. These data support a model in which acidification and receptor binding result in a conformational change in E2 in preparation for membrane fusion.
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A conserved epitope III on hepatitis C virus E2 protein has alternate conformations facilitating cell binding or virus neutralization. Proc Natl Acad Sci U S A 2021; 118:2104242118. [PMID: 34260404 PMCID: PMC8285954 DOI: 10.1073/pnas.2104242118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Epitope III, a highly conserved amino acid motif of 524APTYSW529 on the hepatitis C virus (HCV) E2 glycoprotein, resides in the critical loop that binds to the host receptor CD81, thus making it one of the most important antibody targets for blocking HCV infections. Here, we have determined the X-ray crystal structure of epitope III at a 2.0-Å resolution when it was captured by a site-specific neutralizing antibody, monoclonal antibody 1H8 (mAb1H8). The snapshot of this complex revealed that epitope III has a relatively rigid structure when confined in the binding grooves of mAb1H8, which confers the residue specificity at both ends of the epitope. Such a high shape complementarity is reminiscent of the "lock and key" mode of action, which is reinforced by the incompatibility of an antibody binding with an epitope bearing specific mutations. By subtly positioning the side chains on the three residues of Tyr527, Ser528, and Trp529 while preserving the spatial rigidity of the rest, epitope III in this cocrystal complex adopts a unique conformation that is different from previously described E2 structures. With further analyses of molecular docking and phage display-based peptide interactions, we recognized that it is the arrangements of two separate sets of residues within epitope III that create these discrete conformations for the epitope to interact selectively with either mAb1H8 or CD81. These observations thus raise the possibility that local epitope III conformational dynamics, in conjunction with sequence variations, may act as a regulatory mechanism to coordinate "mAb1H8-like" antibody-mediated immune defenses with CD81-initiated HCV infections.
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Vasiliauskaite I, Owsianka A, England P, Khan AG, Cole S, Bankwitz D, Foung SKH, Pietschmann T, Marcotrigiano J, Rey FA, Patel AH, Krey T. Conformational Flexibility in the Immunoglobulin-Like Domain of the Hepatitis C Virus Glycoprotein E2. mBio 2017; 8:e00382-17. [PMID: 28512091 PMCID: PMC5433095 DOI: 10.1128/mbio.00382-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 04/24/2017] [Indexed: 12/16/2022] Open
Abstract
The hepatitis C virus (HCV) glycoprotein E2 is the major target of neutralizing antibodies and is therefore highly relevant for vaccine design. Its structure features a central immunoglobulin (Ig)-like β-sandwich that contributes to the binding site for the cellular receptor CD81. We show that a synthetic peptide corresponding to a β-strand of this Ig-like domain forms an α-helix in complex with the anti-E2 antibody DAO5, demonstrating an inside-out flip of hydrophobic residues and a secondary structure change in the composite CD81 binding site. A detailed interaction analysis of DAO5 and cross-competing neutralizing antibodies with soluble E2 revealed that the Ig-like domain is trapped by different antibodies in at least two distinct conformations. DAO5 specifically captures retrovirus particles bearing HCV glycoproteins (HCVpp) and infectious cell culture-derived HCV particles (HCVcc). Infection of cells by DAO5-captured HCVpp can be blocked by a cross-competing neutralizing antibody, indicating that a single virus particle simultaneously displays E2 molecules in more than one conformation on its surface. Such conformational plasticity of the HCV E2 receptor binding site has important implications for immunogen design.IMPORTANCE Recent advances in the treatment of hepatitis C virus (HCV) infection with direct-acting antiviral drugs have enabled the control of this major human pathogen. However, due to their high costs and limited accessibility in combination with the lack of awareness of the mostly asymptomatic infection, there is an unchanged urgent need for an effective vaccine. The viral glycoprotein E2 contains regions that are crucial for virus entry into the host cell, and antibodies that bind to these regions can neutralize infection. One of the major targets of neutralizing antibodies is the central immunoglobulin (Ig)-like domain within E2. We show here that this Ig-like domain is conformationally flexible at the surface of infectious HCV particles and pseudoparticles. Our study provides novel insights into the interactions of HCV E2 with the humoral immune system that should aid future vaccine development.
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Affiliation(s)
- Ieva Vasiliauskaite
- Unité de Virologie Structurale, Department Virologie, Institut Pasteur, Paris, France
- CNRS UMR 3569, Paris, France
| | - Ania Owsianka
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Patrick England
- Plate-Forme de Biophysique Moléculaire, Institut Pasteur, Paris, France
- CNRS UMR 3528, Paris, France
| | - Abdul Ghafoor Khan
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Sarah Cole
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Dorothea Bankwitz
- Institute for Experimental Virology, Centre for Experimental and Clinical Infection Research, Twincore, Hannover, Germany
| | - Steven K H Foung
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
| | - Thomas Pietschmann
- Institute for Experimental Virology, Centre for Experimental and Clinical Infection Research, Twincore, Hannover, Germany
- German Center for Infection Research, Hannover-Braunschweig Site, Germany
| | - Joseph Marcotrigiano
- Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Felix A Rey
- Unité de Virologie Structurale, Department Virologie, Institut Pasteur, Paris, France
- CNRS UMR 3569, Paris, France
| | - Arvind H Patel
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Thomas Krey
- Unité de Virologie Structurale, Department Virologie, Institut Pasteur, Paris, France
- CNRS UMR 3569, Paris, France
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research, Hannover-Braunschweig Site, Germany
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Chang CC, Hsu HJ, Yen JH, Lo SY, Liou JW. A Sequence in the loop domain of hepatitis C virus E2 protein identified in silico as crucial for the selective binding to human CD81. PLoS One 2017; 12:e0177383. [PMID: 28481946 PMCID: PMC5421814 DOI: 10.1371/journal.pone.0177383] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/26/2017] [Indexed: 12/15/2022] Open
Abstract
Hepatitis C virus (HCV) is a species-specific pathogenic virus that infects only humans and chimpanzees. Previous studies have indicated that interactions between the HCV E2 protein and CD81 on host cells are required for HCV infection. To determine the crucial factors for species-specific interactions at the molecular level, this study employed in silico molecular docking involving molecular dynamic simulations of the binding of HCV E2 onto human and rat CD81s. In vitro experiments including surface plasmon resonance measurements and cellular binding assays were applied for simple validations of the in silico results. The in silico studies identified two binding regions on the HCV E2 loop domain, namely E2-site1 and E2-site2, as being crucial for the interactions with CD81s, with the E2-site2 as the determinant factor for human-specific binding. Free energy calculations indicated that the E2/CD81 binding process might follow a two-step model involving (i) the electrostatic interaction-driven initial binding of human-specific E2-site2, followed by (ii) changes in the E2 orientation to facilitate the hydrophobic and van der Waals interaction-driven binding of E2-site1. The sequence of the human-specific, stronger-binding E2-site2 could serve as a candidate template for the future development of HCV-inhibiting peptide drugs.
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Affiliation(s)
- Chun-Chun Chang
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.,Department of Laboratory Medicine, Tzu Chi Medical Center, Hualien, Taiwan
| | - Hao-Jen Hsu
- Department of Life Sciences, Tzu Chi University, Hualien, Taiwan
| | - Jui-Hung Yen
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien, Taiwan
| | - Shih-Yen Lo
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Je-Wen Liou
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan.,Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan
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A view of the E2-CD81 interface at the binding site of a neutralizing antibody against hepatitis C virus. J Virol 2014; 89:492-501. [PMID: 25339761 DOI: 10.1128/jvi.01661-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Hepatitis C virus (HCV) glycoprotein E2 is considered a major target for generating neutralizing antibodies against HCV, primarily due to its role of engaging host entry factors, such as CD81, a key cell surface protein associated with HCV entry. Based on a series of biochemical analyses in combination with molecular docking, we present a description of a potential binding interface formed between the E2 protein and CD81. The virus side of this interface includes a hydrophobic helix motif comprised of residues W(437)LAGLF(442), which encompasses the binding site of a neutralizing monoclonal antibody, mAb41. The helical conformation of this motif provides a structural framework for the positioning of residues F442 and Y443, serving as contact points for the interaction with CD81. The cell side of this interface likewise involves a surface-exposed hydrophobic helix, namely, the D-helix of CD81, which coincides with the binding site of 1D6, a monoclonal anti-CD81 antibody known to block HCV entry. Our illustration of this virus-host interface suggests an important role played by the W(437)LAGLF(442) helix of the E2 protein in the hydrophobic interaction with the D-helix of CD81, thereby facilitating our understanding of the mechanism for antibody-mediated neutralization of HCV. IMPORTANCE Characterization of the interface established between a virus and host cells can provide important information that may be used for the control of virus infections. The interface that enables hepatitis C virus (HCV) to infect human liver cells has not been well understood because of the number of cell surface proteins, factors, and conditions found to be associated with the infection process. Based on a series of biochemical analyses in combination with molecular docking, we present such an interface, consisting of two hydrophobic helical structures, from the HCV E2 surface glycoprotein and the CD81 protein, a major host cell receptor recognized by all HCV strains. Our study reveals the critical role played by hydrophobic interactions in the formation of this virus-host interface, thereby contributing to our understanding of the mechanism for antibody-mediated neutralization of HCV.
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Discrete conformations of epitope II on the hepatitis C virus E2 protein for antibody-mediated neutralization and nonneutralization. Proc Natl Acad Sci U S A 2014; 111:10690-5. [PMID: 25002515 PMCID: PMC4115556 DOI: 10.1073/pnas.1411317111] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The X-ray crystal structure of epitope II on the E2 protein of hepatitis C virus, in complex with nonneutralizing antibody mAb#12, has been solved at 2.90-Å resolution. The spatial arrangement of the essential components of epitope II (ie, the C-terminal α-helix and the N-terminal loop) was found to deviate significantly from that observed in those corresponding complexes with neutralizing antibodies. The distinct conformations are mediated largely by the flexibility of a highly conserved glycine residue that connects these components. Thus, it is the particular tertiary structure of epitope II, which is presented in a spatial and temporal manner, that determines the specificity of antibody recognition and, consequently, the outcome of neutralization or nonneutralization.
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Unexpected structural features of the hepatitis C virus envelope protein 2 ectodomain. J Virol 2014; 88:10280-8. [PMID: 24991010 DOI: 10.1128/jvi.00874-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hepatitis C virus (HCV), a member of the family Flaviviridae, is a leading cause of chronic liver disease and cancer. Recent advances in HCV therapeutics have resulted in improved cure rates, but an HCV vaccine is not available and is urgently needed to control the global pandemic. Vaccine development has been hampered by the lack of high-resolution structural information for the two HCV envelope glycoproteins, E1 and E2. Recently, Kong and coworkers (Science 342:1090-1094, 2013, doi:10.1126/science.1243876) and Khan and coworkers (Nature 509[7500]:381-384, 2014, doi:10.1038/nature13117) independently determined the structure of the HCV E2 ectodomain core with some unexpected and informative results. The HCV E2 ectodomain core features a globular architecture with antiparallel β-sheets forming a central β sandwich. The residues comprising the epitopes of several neutralizing and nonneutralizing human monoclonal antibodies were also determined, which is an essential step toward obtaining a fine map of the human humoral response to HCV. Also clarified were the regions of E2 that directly bind CD81, an important HCV cellular receptor. While it has been widely assumed that HCV E2 is a class II viral fusion protein (VFP), the newly determined structure suggests that the HCV E2 ectodomain shares structural and functional similarities only with domain III of class II VFPs. The new structural determinations suggest that the HCV glycoproteins use a different mechanism than that used by class II fusion proteins for cell fusion.
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Kato N, Sejima H, Ueda Y, Mori K, Satoh S, Dansako H, Ikeda M. Genetic characterization of hepatitis C virus in long-term RNA replication using Li23 cell culture systems. PLoS One 2014; 9:e91156. [PMID: 24625789 PMCID: PMC3953375 DOI: 10.1371/journal.pone.0091156] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 02/10/2014] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The most distinguishing genetic feature of hepatitis C virus (HCV) is its remarkable diversity and variation. To understand this feature, we previously performed genetic analysis of HCV in the long-term culture of human hepatoma HuH-7-derived HCV RNA-replicating cell lines. On the other hand, we newly established HCV RNA-replicating cell lines using human hepatoma Li23 cells, which were distinct from HuH-7 cells. METHODOLOGY/PRINCIPAL FINDINGS Li23-derived HCV RNA-replicating cells were cultured for 4 years. We performed genetic analysis of HCVs recovered from these cells at 0, 2, and 4 years in culture. Most analysis was performed in two separate parts: one part covered from the 5'-terminus to NS2, which is mostly nonessential for RNA replication, and the other part covered from NS3 to NS5B, which is essential for RNA replication. Genetic mutations in both regions accumulated in a time-dependent manner, and the mutation rates in the 5'-terminus-NS2 and NS3-NS5B regions were 4.0-9.0×10(-3) and 2.7-4.0×10(-3) base substitutions/site/year, respectively. These results suggest that the variation in the NS3-NS5B regions is affected by the pressure of RNA replication. Several in-frame deletions (3-105 nucleotides) were detected in the structural regions of HCV RNAs obtained from 2-year or 4-year cultured cells. Phylogenetic tree analyses clearly showed that the genetic diversity of HCV was expanded in a time-dependent manner. The GC content of HCV RNA was significantly increased in a time-dependent manner, as previously observed in HuH-7-derived cell systems. This phenomenon was partially due to the alterations in codon usages for codon optimization in human cells. Furthermore, we demonstrated that these long-term cultured cells were useful as a source for the selection of HCV clones showing resistance to anti-HCV agents. CONCLUSIONS/SIGNIFICANCE Long-term cultured HCV RNA-replicating cells are useful for the analysis of evolutionary dynamics and variations of HCV and for drug-resistance analysis.
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Affiliation(s)
- Nobuyuki Kato
- Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Shikata-cho, Okayama, Japan
- * E-mail:
| | - Hiroe Sejima
- Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Shikata-cho, Okayama, Japan
| | - Youki Ueda
- Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Shikata-cho, Okayama, Japan
| | - Kyoko Mori
- Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Shikata-cho, Okayama, Japan
| | - Shinya Satoh
- Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Shikata-cho, Okayama, Japan
| | - Hiromichi Dansako
- Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Shikata-cho, Okayama, Japan
| | - Masanori Ikeda
- Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Shikata-cho, Okayama, Japan
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