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Si J, Li J, Zhang L, Zhang W, Yao J, Li T, Wang W, Zhu W, Allain JP, Fu Y, Li C. A signal amplification system on a lateral flow immunoassay detecting for hepatitis e-antigen in human blood samples. J Med Virol 2019; 91:1301-1306. [PMID: 30851129 DOI: 10.1002/jmv.25452] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 03/04/2019] [Accepted: 03/06/2019] [Indexed: 01/11/2023]
Abstract
Hepatitis B e-antigen (HBeAg) is the secretory form of the nucleocapsid of the hepatitis B virus (HBV), which is a marker of viral replication. In this study, a novel signal amplification system (SAS) based on the lateral flow immunoassay (LFIA) was used for rapid detection of HBeAg in blood samples from patients or blood donors. In this assay, the detection antibody was conjugated with gold nanoparticles (GNPs), and the capture antibody was labeled with biotin. The presence of targeting antigen HBeAg in blood sample would act as a bridge with biotinylated captured antibody and GNP-conjugated detection antibody to form the dendritic nanoparticle complex. The dendritic complexes in the sample solution were migrated and immobilized on the testing line of strip coated with antibiotin antibodies. Signal intensity was massively amplified by the SAS, which was positively correlated with the concentration of targeting antigen in the blood sample and was assessed by eyes or strip scanner. The SAS worked only when targeting antigens were present in the sample. By using this SAS-LFIA, we were able to detect a very low concentration of HBeAg (9 ng/mL), which was 27-fold sensitive than that by conventional LFIA (cLFIA). A number of 420 blood samples were detested by this novel SAS-LFIA, the results were in accordance with those of enzyme-linked immunosorbent assay (ELISA) completely, while the cLFIA missed an HBeAg-positive sample. In conclusion, the novel SAS has high specificity and sensitivity, which can be used to replace the conventional rapid test and ELISA in clinical diagnosis.
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Affiliation(s)
- Jinhong Si
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Jinfeng Li
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China.,Shenzhen Key Laboratory of Molecular Epidemiology, Center for Disease Control and Prevention (CDC), Shenzhen, China
| | - Ling Zhang
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Weiyun Zhang
- Laboratory Department, Military General Hospital of Guangzhou, Guangzhou, China
| | - Jinxiu Yao
- Laboratory Department, Yangjiang People's Hospital, Yangjiang, Guangdong, China
| | - Tingting Li
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Wenjing Wang
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China
| | - Weihang Zhu
- Department of Blood Donation Screening, Shenzhen Blood Center, Shenzhen, China
| | - Jean-Pierre Allain
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China.,Emeritus Professor, University of Cambridge, Cambridge, UK
| | - Yongshui Fu
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China.,Insitutue of Clinical Transfusion, Guangzhou Blood Center, Guangzhou, China
| | - Chengyao Li
- Department of Transfusion Medicine, School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, China.,School of Public Health, Southern Medical University, Guangzhou, China
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2
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Monoclonal antibodies: Principles and applications of immmunodiagnosis and immunotherapy for hepatitis C virus. World J Hepatol 2015. [PMID: 26464752 DOI: 10.4254/wjh.v7.i22.2369.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Hepatitis C virus (HCV) is a major health problem worldwide. Early detection of the infection will help better management of the infected cases. The monoclonal antibodies (mAb) of mice are predominantly used for the immunodiagnosis of several viral, bacterial, and parasitic antigens. Serological detection of HCV antigens and antibodies provide simple and rapid methods of detection but lack sensitivity specially in the window phase between the infection and antibody development. Human mAb are used in the immunotherapy of several blood malignancies, such as lymphoma and leukemia, as well as for autoimmune diseases. In this review article, we will discuss methods of mouse and human monoclonal antibody production. We will demonstrate the role of mouse mAb in the detection of HCV antigens as rapid and sensitive immunodiagnostic assays for the detection of HCV, which is a major health problem throughout the world, particularly in Egypt. We will discuss the value of HCV-neutralizing antibodies and their roles in the immunotherapy of HCV infections and in HCV vaccine development. We will also discuss the different mechanisms by which the virus escape the effect of neutralizing mAb. Finally, we will discuss available and new trends to produce antibodies, such as egg yolk-based antibodies (IgY), production in transgenic plants, and the synthetic antibody mimics approach.
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3
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Campo DS, Dimitrova Z, Yokosawa J, Hoang D, Perez NO, Ramachandran S, Khudyakov Y. Hepatitis C virus antigenic convergence. Sci Rep 2012; 2:267. [PMID: 22355779 PMCID: PMC3279735 DOI: 10.1038/srep00267] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 01/20/2012] [Indexed: 12/13/2022] Open
Abstract
Vaccine development against hepatitis C virus (HCV) is hindered by poor understanding of factors defining cross-immunoreactivity among heterogeneous epitopes. Using synthetic peptides and mouse immunization as a model, we conducted a quantitative analysis of cross-immunoreactivity among variants of the HCV hypervariable region 1 (HVR1). Analysis of 26,883 immunological reactions among pairs of peptides showed that the distribution of cross-immunoreactivity among HVR1 variants was skewed, with antibodies against a few variants reacting with all tested peptides. The HVR1 cross-immunoreactivity was accurately modeled based on amino acid sequence alone. The tested peptides were mapped in the HVR1 sequence space, which was visualized as a network of 11,319 sequences. The HVR1 variants with a greater network centrality showed a broader cross-immunoreactivity. The entire sequence space is explored by each HCV genotype and subtype. These findings indicate that HVR1 antigenic diversity is extensively convergent and effectively limited, suggesting significant implications for vaccine development.
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Affiliation(s)
- David S. Campo
- Molecular Epidemiology & Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, USA, 30329
| | - Zoya Dimitrova
- Molecular Epidemiology & Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, USA, 30329
| | - Jonny Yokosawa
- Molecular Epidemiology & Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, USA, 30329
- Laboratório de Virologia, Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Uberlândia, Brazil
| | - Duc Hoang
- Molecular Epidemiology & Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, USA, 30329
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | - Nestor O. Perez
- Molecular Epidemiology & Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, USA, 30329
- Probiomed S.A., Tenancingo, Mexico
| | - Sumathi Ramachandran
- Molecular Epidemiology & Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, USA, 30329
| | - Yury Khudyakov
- Molecular Epidemiology & Bioinformatics Laboratory, Division of Viral Hepatitis, Centers for Disease Control and Prevention, Atlanta, USA, 30329
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4
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Helle F, Duverlie G, Dubuisson J. The hepatitis C virus glycan shield and evasion of the humoral immune response. Viruses 2011; 3:1909-32. [PMID: 22069522 PMCID: PMC3205388 DOI: 10.3390/v3101909] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 09/28/2011] [Accepted: 10/01/2011] [Indexed: 12/14/2022] Open
Abstract
Despite the induction of effective immune responses, 80% of hepatitis C virus (HCV)-infected individuals progress from acute to chronic hepatitis. In contrast to the cellular immune response, the role of the humoral immune response in HCV clearance is still subject to debate. Indeed, HCV escapes neutralizing antibodies in chronically infected patients and reinfection has been described in human and chimpanzee. Studies of antibody-mediated HCV neutralization have long been hampered by the lack of cell-culture-derived virus and the absence of a small animal model. However, the development of surrogate models and recent progress in HCV propagation in vitro now enable robust neutralization assays to be performed. These advances are beginning to shed some light on the mechanisms of HCV neutralization. This review summarizes the current state of knowledge of the viral targets of anti-HCV-neutralizing antibodies and the mechanisms that enable HCV to evade the humoral immune response. The recent description of the HCV glycan shield that reduces the immunogenicity of envelope proteins and masks conserved neutralizing epitopes at their surface constitutes the major focus of this review.
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Affiliation(s)
- François Helle
- Laboratory of Virology, EA4294, Jules Verne University of Picardie, Amiens 80000, France; E-Mail:
| | - Gilles Duverlie
- Laboratory of Virology, EA4294, Jules Verne University of Picardie, Amiens 80000, France; E-Mail:
- Virology Department, Amiens University Hospital Center, South Hospital, Amiens 80000, France
| | - Jean Dubuisson
- Inserm U1019, CNRS UMR8204, Center for Infection and Immunity of Lille (CIIL), Institut Pasteur de Lille, Université Lille Nord de France, Lille 59021, France; E-Mail:
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5
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Uhde-Holzem K, Schlösser V, Viazov S, Fischer R, Commandeur U. Immunogenic properties of chimeric potato virus X particles displaying the hepatitis C virus hypervariable region I peptide R9. J Virol Methods 2010; 166:12-20. [PMID: 20138085 DOI: 10.1016/j.jviromet.2010.01.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 01/20/2010] [Accepted: 01/25/2010] [Indexed: 12/11/2022]
Abstract
The immunogenic properties of chimeric potato virus X (PVX) particles engineered to display the synthetic R9 peptide have been evaluated. The R9 peptide is a consensus sequence derived from diverse variants of the hypervariable region 1 from the hepatitis C virus (HCV) envelope protein E2. Two different constructs were designed, with the R9 peptide expressed either as an indirect fusion via the ribosomal skip 2A (PVX(R9-2A)CP) sequence or as a direct PVX coat protein fusion (PVX(R9)CP). Systemic infection of Nicotiana benthamiana plants was only achieved with PVX(R9-2A)CP constructs, and the presence of the R9 peptide was detected in extracts from these plants by ELISA, Western blot and electron microscopy using specific anti-R9 antibodies. The virus particles were recovered at yields of up to 125mg/kg from leaf material. BALB/c mice immunized with purified PVX(R9-2A)CP particles developed specific anti-R9 IgG titers of up to 1:50,000. Monoclonal anti-R9 antibodies were obtained from the spleen of a mouse immunized with PVX(R9-2A)CP particles and characterized by Western blot and electron microscopy. Sera from patients infected chronically with HCV were found to react specifically with PVX(R9-2A)CP particles in 35% of cases.
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Affiliation(s)
- Kerstin Uhde-Holzem
- Institute for Molecular Biotechnology (Biology VII), RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
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6
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Hua RH, Wu DL, Tong GZ, Wang YF, Tian ZJ, Zhou YJ. [Identification of mimotope peptides which bind to the SARS-CoV spike protein specific monoclonal antibody 2C5 with phage-displayed peptides library]. SHENG WU GONG CHENG XUE BAO = CHINESE JOURNAL OF BIOTECHNOLOGY 2010; 22:701-6. [PMID: 17037189 PMCID: PMC7147893 DOI: 10.1016/s1872-2075(06)60051-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
This article aims to identify the epitope corresponding to SARS-CoV spike protein specific neutralizing monoclonal antibody (MAb) 2C5. The antibody was used as the target and three rounds of bio-panning were conducted with a phage-displayed peptide library. After the third panning, 20 phage-plaque clones were randomly picked and analyzed for the binding ability with the MAb 2C5 by ELISA. The displayed sequence analysis demonstrated that among the 20 phage clones, eight clones displayed the same seven-peptide TPEQQFT. All these eight phage-clones showed strongest binding activity with 2C5 in the phage ELISA analysis. Furthermore, phages displaying peptide TPEQQFT could specifically inhibit the binding of MAb 2C5 with SARS-CoV spike protein. The results demonstrated that TPEQQFT is a mimic epitope peptide containing neutralizing MAb 2C5. This study may provide information for further structural and functional analyses of spike protein and vaccine development for severe acute respiratory syndrome.
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Affiliation(s)
- Rong-Hong Hua
- Notional Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural of Science
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7
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Keck ZY, Machida K, Lai MMC, Ball JK, Patel AH, Foung SKH. Therapeutic control of hepatitis C virus: the role of neutralizing monoclonal antibodies. Curr Top Microbiol Immunol 2008; 317:1-38. [PMID: 17990788 DOI: 10.1007/978-3-540-72146-8_1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Liver failure associated with hepatitis C virus (HCV) accounts for a substantial portion of liver transplantation. Although current therapy helps some patients with chronic HCV infection, adverse side effects and a high relapse rate are major problems. These problems are compounded in liver transplant recipients as reinfection occurs shortly after transplantation. One approach to control reinfection is the combined use of specific antivirals together with HCV-specific antibodies. Indeed, a number of human and mouse monoclonal antibodies to conformational and linear epitopes on HCV envelope proteins are potential candidates, since they have high virus neutralization potency and are directed to epitopes conserved across diverse HCV genotypes. However, a greater understanding of the factors contributing to virus escape and the role of lipoproteins in masking virion surface domains involved in virus entry will be required to help define those protective determinants most likely to give broad protection. An approach to immune escape is potentially caused by viral infection of immune cells leading to the induction hypermutation of the immunoglobulin gene in B cells. These effects may contribute to HCV persistence and B cell lymphoproliferative diseases.
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Affiliation(s)
- Z Y Keck
- Department of Pathology, Stanford Medical School Blood Center, Palo Alto, CA 94304, USA
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8
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Helle F, Goffard A, Morel V, Duverlie G, McKeating J, Keck ZY, Foung S, Penin F, Dubuisson J, Voisset C. The neutralizing activity of anti-hepatitis C virus antibodies is modulated by specific glycans on the E2 envelope protein. J Virol 2007; 81:8101-11. [PMID: 17522218 PMCID: PMC1951279 DOI: 10.1128/jvi.00127-07] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Hepatitis C virus (HCV) envelope glycoproteins are highly glycosylated, with up to 5 and 11 N-linked glycans on E1 and E2, respectively. Most of the glycosylation sites on HCV envelope glycoproteins are conserved, and some of the glycans associated with these proteins have been shown to play an essential role in protein folding and HCV entry. Such a high level of glycosylation suggests that these glycans can limit the immunogenicity of HCV envelope proteins and restrict the binding of some antibodies to their epitopes. Here, we investigated whether these glycans can modulate the neutralizing activity of anti-HCV antibodies. HCV pseudoparticles (HCVpp) bearing wild-type glycoproteins or mutants at individual glycosylation sites were evaluated for their sensitivity to neutralization by antibodies from the sera of infected patients and anti-E2 monoclonal antibodies. While we did not find any evidence that N-linked glycans of E1 contribute to the masking of neutralizing epitopes, our data demonstrate that at least three glycans on E2 (denoted E2N1, E2N6, and E2N11) reduce the sensitivity of HCVpp to antibody neutralization. Importantly, these three glycans also reduced the access of CD81 to its E2 binding site, as shown by using a soluble form of the extracellular loop of CD81 in inhibition of entry. These data suggest that glycans E2N1, E2N6, and E2N11 are close to the binding site of CD81 and modulate both CD81 and neutralizing antibody binding to E2. In conclusion, this work indicates that HCV glycans contribute to the evasion of HCV from the humoral immune response.
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Affiliation(s)
- François Helle
- Institut de Biologie de Lille (UMR8161), CNRS, Université Lille I and II and Institut Pasteur de Lille, Lille, France
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9
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Grollo L, Torresi J, Drummer H, Zeng W, Williamson N, Jackson DC. Exploiting Information Inherent in Binding Sites of Virus-Specific Antibodies: Design of An HCV Vaccine Candidate Cross-Reactive with Multiple Genotypes. Antivir Ther 2006. [DOI: 10.1177/135965350601100809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background/Aims The role of antibody in hepatitis C virus (HCV) infection remains unclear although many reports attest to its role in viral clearance. Here we describe epitopes that are recognized by antibody present in the serum of infected patients and show that such epitopes can induce neutralizing antibodies. Methods Human serum containing hyperimmune anti-HCV IgG was used to extract epitopes from a library of synthetic peptides that encompassed the sequences of the E1 and E2 proteins of HCV genotype 1a H77. Peptides that were bound by IgG were identified by mass spectrometry. Assembly of these epitopes with a helper T cell determinant was then carried out in order to construct candidate epitope-based vaccines. Results Three distinct antigenic sites were defined in the E1E2 glycoproteins by epitopes identified by antibody present in infected individuals. Four of the peptide epitopes identified are conserved in at least three HCV genotypes and are bound by antibody present in the sera of chronically infected and convalescent individuals. Synthetic vaccines based on these epitopes elicited antibodies that are capable of (i) capturing HCV virions from the serum of viraemic patients and (ii) inhibiting HCV pseudovirus particle entry into Huh7 cells. Conclusions This approach exploits the information inherent in the binding sites of virus-specific antibodies and represents a novel method for the design of synthetic epitope-based vaccines.
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Affiliation(s)
- Lara Grollo
- Cooperative Research Centre for Vaccine Technology, Department of Microbiology & Immunology, The University of Melbourne, Parkville, VIC, Australia
| | - Joseph Torresi
- Department of Medicine and Center for Clinical Research Excellence, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Heidi Drummer
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, VIC, Australia
| | - Weiguang Zeng
- Cooperative Research Centre for Vaccine Technology, Department of Microbiology & Immunology, The University of Melbourne, Parkville, VIC, Australia
| | - Nicholas Williamson
- Cooperative Research Centre for Vaccine Technology, Department of Microbiology & Immunology, The University of Melbourne, Parkville, VIC, Australia
| | - David C Jackson
- Cooperative Research Centre for Vaccine Technology, Department of Microbiology & Immunology, The University of Melbourne, Parkville, VIC, Australia
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10
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Abstract
Hepatitis C virus (HCV) exists in different forms in the circulation of infected people: lipoprotein bound and lipoprotein free, enveloped and nonenveloped. Viral particles with the highest infectivity are associated with lipoproteins, whereas lipoprotein-free virions are poorly infectious. The detection of HCV's envelope proteins E1 and E2 in lipoprotein-associated virions has been challenging. Because lipoproteins are readily endocytosed, some forms of HCV might utilize their association with lipoproteins rather than E1 and E2 for cell attachment and internalization. However, vaccination of chimpanzees with recombinant envelope proteins protected the animals from hepatitis C infection, suggesting an important role for E1 and E2 in cell entry. It seems possible that different forms of HCV use different receptors to attach to and enter cells. The putative receptors and the assays used for their validation are discussed in this review.
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11
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Yan J, Ling S, Liu H, Zhang H, Song X, Xiu B, Chen K, Wang G, Zhu C. Induction of strong cytotoxic T-lymphocyte responses to hepatitis C virus with recombinant poly-epitope in BALB/c mice. Viral Immunol 2006; 19:64-73. [PMID: 16553551 DOI: 10.1089/vim.2006.19.64] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- J Yan
- Department of Vaccine Engineering, Beijing Institute of Basic Medical Sciences, Beijing, China
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12
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Nielsen SU, Bassendine MF, Burt AD, Martin C, Pumeechockchai W, Toms GL. Association between hepatitis C virus and very-low-density lipoprotein (VLDL)/LDL analyzed in iodixanol density gradients. J Virol 2006; 80:2418-28. [PMID: 16474148 PMCID: PMC1395398 DOI: 10.1128/jvi.80.5.2418-2428.2006] [Citation(s) in RCA: 256] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hepatitis C virus (HCV) RNA circulates in the blood of persistently infected patients in lipoviroparticles (LVPs), which are heterogeneous in density and associated with host lipoproteins and antibodies. The variability and lability of these virus-host complexes on fractionation has hindered our understanding of the structure of LVP and determination of the physicochemical properties of the HCV virion. In this study, HCV from an antibody-negative immunodeficient patient was analyzed using three fractionation techniques, NaBr gradients, isotonic iodixanol, and sucrose gradient centrifugation. Iodixanol gradients were shown to best preserve host lipoprotein-virus complexes, and all HCV RNA was found at densities below 1.13 g/ml, with the majority at low density, < or =1.08 g/ml. Immunoprecipitation with polyclonal antibodies against human ApoB and ApoE precipitated 91.8% and 95.0% of HCV with low density, respectively, suggesting that host lipoprotein is closely associated with HCV in a particle resembling VLDL. Immunoprecipitation with antibodies against glycoprotein E2 precipitated 25% of HCV with low density, providing evidence for the presence of E2 in LVPs. Treatment of serum with 0.5% deoxycholic acid in the absence of salt produced HCV with a density of 1.12 g/ml and a sedimentation coefficient of 215S. The diameters of these particles were calculated as 54 nm. Treatment of serum with 0.18% NP-40 produced HCV with a density of 1.18 g/ml, a sedimentation coefficient of 180S, and a diameter of 42 nm. Immunoprecipitation analysis showed that ApoB remained associated with HCV after treatment of serum with deoxycholic acid or NP-40, whereas ApoE was removed from HCV with these detergents.
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Affiliation(s)
- Søren U Nielsen
- Liver Research Group, School of Clinical Medical Sciences, University of Newcastle, England.
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13
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Owsianka A, Tarr AW, Juttla VS, Lavillette D, Bartosch B, Cosset FL, Ball JK, Patel AH. Monoclonal antibody AP33 defines a broadly neutralizing epitope on the hepatitis C virus E2 envelope glycoprotein. J Virol 2005; 79:11095-104. [PMID: 16103160 PMCID: PMC1193588 DOI: 10.1128/jvi.79.17.11095-11104.2005] [Citation(s) in RCA: 234] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Accepted: 06/01/2005] [Indexed: 02/03/2023] Open
Abstract
Hepatitis C virus (HCV) remains a significant threat to the general health of the world's population, and there is a pressing need for the development of new treatments and preventative vaccines. Here, we describe the generation of retrovirus-based pseudoparticles (HCVpp) incorporating a panel of full-length E1E2 clones representative of the major genotypes 1 through 6, and their application to assess the reactivity and neutralizing capability of antisera and monoclonal antibodies raised against portions of the HCV E2 envelope protein. Rabbit antisera raised against either the first hypervariable region or ectodomain of E2 showed limited and strain specific neutralization. By contrast, the monoclonal antibody (MAb) AP33 demonstrated potent neutralization of infectivity against HCVpp carrying E1E2 representative of all genotypes tested. The concentration of AP33 required to achieve 50% inhibition of infection by HCVpp of diverse genotypes ranged from 0.6 to 32 mug/ml. The epitope recognized by MAb AP33 is linear and highly conserved across different genotypes of HCV. Thus, identification of a broadly neutralizing antibody that recognizes a linear epitope is likely to be of significant benefit to future vaccine and therapeutic antibody development.
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Affiliation(s)
- Ania Owsianka
- MRC Virology Unit, Institute of Virology, University of Glasgow, UK
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14
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Li C, Allain JP. Chimeric monoclonal antibodies to hypervariable region 1 of hepatitis C virus. J Gen Virol 2005; 86:1709-1716. [PMID: 15914849 DOI: 10.1099/vir.0.80912-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Two chimeric monoclonal antibodies (cAbs), 2P24 and 15H4, to hypervariable region 1 (HVR1) of hepatitis C virus (HCV) were constructed by grafting the variable regions of murine monoclonal antibodies (mAbs) 2P24 and 15H4 to a human IgG1 kappa constant region. Two cAb-producing cell lines were adapted to serum-free media. Both cAb 2P24 and cAb 15H4 cell lines produced 3-5 microg antibodies ml(-1) after 3-5 days culture. cAbs retained binding characteristics similar to those observed in the original mAbs. There was no clear difference in affinity between binding of cAbs and mAbs to seven HVR1 peptides. Mixtures of biotinylated cAbs or mAbs reacted with 32 (86 %) and 31 (84 %) of 37 HVR1 peptides, respectively, but not with non-HVR1 control peptides. HCV from 16 out of 18 (89 %) random HCV-containing plasmas was captured by the mixture of biotinylated cAbs. The capture from IgG-depleted plasmas suggested that cAbs captured mainly free rather than complexed HCV, irrespective of genotype. A mixture of the two cAbs inhibited HCV binding to Molt-4 cells in a dose-dependent manner. These cAbs may be useful for prevention of nosocomial HCV infection and passive immunization to prevent HCV reinfection after liver transplantation.
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Affiliation(s)
- Chengyao Li
- National Blood Service, Division of Transfusion Medicine, East Anglia Blood Centre, Long Road, Cambridge CB2 2PT, UK
| | - Jean-Pierre Allain
- Department of Haematology, Division of Transfusion Medicine, East Anglia Blood Centre, Long Road, Cambridge CB2 2PT, UK
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15
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Kurihara C, Tsuzuki Y, Hokari R, Nakashima H, Mataki N, Kuroki M, Kawaguchi A, Nagao S, Kondo T, Miura S. A highly hydrophobic domain within hypervariable region 1 may be related to the entry of hepatitis C virus into cultured human hepatoma cells. J Med Virol 2004; 74:546-55. [PMID: 15484277 DOI: 10.1002/jmv.20213] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Interaction of the envelope glycoprotein of hepatitis C virus (HCV) with a cellular receptor(s) is thought to be essential for the initial steps of HCV infection. However, the mechanisms of HCV infection remain unclear. The aim of the present study was to determine the features of HCV that enable efficient entry of the virus into human hepatocytes. Variations of hypervariable region 1 (HVR1) sequences in HCV inocula and in infected human hepatoblastoma HepG2 cells were examined. Immunofluorescence of inoculated HepG2 cells with anti-HCV core antibodies demonstrated that HCV structural proteins were expressed in the cytoplasm, and their entry into HepG2 cells was confirmed. When the HVR1 amino acid sequences were compared, HVR1 quasispecies in the inoculated cells showed more uniformity than those of the inocula. Although there were no statistically significant differences between the two groups, hydrophobic residues were observed more frequently in the HVR1 amino acids from inoculated cells than in the HVR1 amino acids from the inocula. Results of hydropathy analysis revealed that highly hydrophobic domains exist in the middle of HVR1 in the inoculated cells in 7 of 10 patients. The results suggest that limited HCV populations are able to enter HepG2 cells and that the highly hydrophobic domain existing within the HVR1 may play an important role in the entry of HCV into cells.
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Affiliation(s)
- Chie Kurihara
- Second Department of Internal Medicine, National Defense Medical College, Saitama, Japan
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16
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Abstract
Hepatitis C virus (HCV) infects over 170 million people worldwide. Chronic infection occurs in 50-80% of cases and eventually leads to cirrhosis and hepatocellular carcinoma. The HCV lifecycle is only partly understood owing to the lack of a productive cell culture system. Several molecules have been implicated in the receptor complex at the surface of target cells, but the mode of HCV entry remains unknown. Persistent infection appears to be due to weak CD4+and CD8+ T-cell responses during acute infection, which fail to control viral replication. When chronic infection is established, HCV does not appear to be cytopathic. Liver lesions appear to result from locally driven immune responses, which are mainly non-specific. Local inflammation triggers fibrogenesis, in which hepatic stellate cells play a major role. Cirrhosis is facilitated by external factors, such as chronic alcohol consumption and viral co-infections. Patients with cirrhosis are at high risk of developing hepatocellular carcinoma. The role of HCV proteins in hepatocarcinogenesis is unknown. Further progress in our understanding of HCV infection and pathogenesis awaits the advent of new model systems and technologies.
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Affiliation(s)
- Jean-Michel Pawlotsky
- Department of Virology (EA 3489), Hôpital Henri Mondor, Université Paris XII, 51 avenue du Maréchal de Lattre de Tassigny, 94010 Créteil, France.
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17
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Zhang XX, Deng Q, Zhang SY, Liu J, Cai Q, Lu ZM, Wang Y. Broadly cross-reactive mimotope of hypervariable region 1 of hepatitis C virus derived from DNA shuffling and screened by phage display library. J Med Virol 2004; 71:511-7. [PMID: 14556263 DOI: 10.1002/jmv.10521] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The hypervariable region 1 (HVR1) is the target of neutralizing antibodies but with isolate specificity. The aim of this study was to obtain immunogenic mimotopes of HVR1, which can react broadly with different HVR1 antibodies and could be one of the candidate immunogens in an effective vaccine against HCV. Thirty-one HVR1 cDNA fragments were digested by DNase I into a pool of random fragments and reassembled by repeated cycles of annealing in the presence of DNA polymerase to their original size. The shuffled HVR1 was then inserted into the gene III phagemid vector pCANTAB-5E and displayed on the surface of the phage. Eight individual phages were selected after four rounds of biopanning against anti-HVR1. ELISA was carried out on immobilized purified phages, respectively, to detect their reactivity with a panel of sera. DNA sequences of the inserts were analyzed and compared with the consensus sequences defined by Puntoriero et al. [(1998) EMBO J 17:3521-3533]. The reactivity of the eight selected clones to the 30 sera were from 53.3 to 80%. Among these, phage 13 (ETYVSGGSAARNAYGLTSLFTVGPAQK, aa 384-410) reacted most broadly. None of the selected sequences encoded for peptides corresponded to known HVR1 from original viral isolates. The two high reactive phages had the similar amino acid sequences with the consensus, which might play a particular role in determining the frequency of reactivity. In conclusion, this study has used effectively DNA shuffling combined with phage display technology to identify broadly cross-reactive mimotopes recognized by human polyclonal antibodies. Mimotope 13 and 23 appeared to be most reactive immunologically and could be candidate immunogens. Efforts are now underway to identify their neutralizing antibodies by immunization of animals.
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Affiliation(s)
- Xin-Xin Zhang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China
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18
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von Wagner M, Lee JH, Rüster B, Kronenberger B, Sarrazin C, Roth WK, Zeuzem S. Dynamics of hepatitis C virus quasispecies turnover during interferon-alpha treatment. J Viral Hepat 2003; 10:413-22. [PMID: 14633173 DOI: 10.1046/j.1365-2893.2003.00457.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Interferon-alpha (IFN) has been shown to accelerate the evolution of hepatitis C virus (HCV) variants (quasispecies) in nonresponder patients. Different sensitivities of HCV variants to IFN are discussed as a possible mechanism. In the present study, quasispecies were investigated in detail by a newly established and validated direct solid-phase sequencing of the hypervariable region 1 (HVR1), during the initial 3 months of IFN therapy. According to single strand conformation polymorphism (SSCP) analysis, 14 of 26 (54%) virologic nonresponders with quasispecies evolution were identified. Six representative patients with SSCP changes were selected for frequent HVR1 sequencing. Pre-existing variants were identified by cloning and sequencing of the pretreatment serum HCV sample. In one patient the major type was substituted by a minor variant within 3 days of treatment while in the majority of patients the pretreatment major type did not decline before days 26-57 of treatment. Total serum HCV RNA levels remained constant in all patients. In conclusion, although quasispecies evolution during IFN therapy is common, it occurs after a wide range of time intervals after initiation of therapy. Thus, nonresponse to IFN cannot exclusively be explained by changes in the quasispecies.
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Affiliation(s)
- M von Wagner
- Innere Medizin II, Universitätskliniken des Saarlandes, Homburg/Saar, Germany
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19
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Frasca L, Scottà C, Del Porto P, Nicosia A, Pasquazzi C, Versace I, Masci AM, Racioppi L, Piccolella E. Antibody-selected mimics of hepatitis C virus hypervariable region 1 activate both primary and memory Th lymphocytes. Hepatology 2003; 38:653-63. [PMID: 12939592 DOI: 10.1053/jhep.2003.50387] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An ideal strategy that leads to a vaccine aimed at controlling viral escape may be that of preventing the replication of escape mutants by eliciting a T- and B-cell repertoire directed against many viral variants. The hypervariable region 1 (HVR1) of the putative envelope 2 protein that presents B and T epitopes shown to induce protective immunity against hepatitis C virus (HCV), might be suitable for this purpose if its immunogenicity can be improved by generating mimics that induce broad, highly cross-reactive, anti-HVR1 responses. Recently we described a successful approach to select HVR1 mimics (mimotopes) incorporating the variability found in a great number of viral variants. In this report we explore whether these mimotopes, designed to mimic B-cell epitopes, also mimic helper T-cell epitopes. The first interesting observation is that mimotopes selected for their reactivity to HVR1-specific antibodies of infected patients also do express HVR1 T-cell epitopes, suggesting that similar constraints govern HVR1-specific humoral and cellular immune responses. Moreover, some HVR1 mimotopes stimulate a multispecific CD4(+) T-cell repertoire that effectively cross-reacts with HVR1 native sequences. This may significantly limit effects as a T-cell receptor (TCR) antagonist frequently exerted by natural HVR1-variants on HVR1-specific T-cell responses. In conclusion, these data lend strong support to using HVR1 mimotopes in vaccines designed to prevent replication of escape mutants.
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Affiliation(s)
- Loredana Frasca
- Department of Cellular and Developmental Biology, La Sapienza University, Rome, Italy
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20
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Xiu BS, Ling SG, Song XG, Zhang HQ, Chen K, Zhu CX. Cross-reactivity of hypervariable region 1 chimera of hepatitis C virus. World J Gastroenterol 2003; 9:1256-60. [PMID: 12800235 PMCID: PMC4611795 DOI: 10.3748/wjg.v9.i6.1256] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2003] [Revised: 02/04/2003] [Accepted: 02/16/2003] [Indexed: 02/06/2023] Open
Abstract
AIM To analyze the amino acid sequences of hypervariable region 1 (HVR1) of HCV isolates in China and to construct a combinatorial chimeric HVR1 protein having a very broad high cross-reactivity. METHODS All of the published HVR1 sequences from China were collected and processed with a computer program. Several representative HVR1's sequences were formulated based on a consensus profile and homology within certain subdivision. A few reported HVR1 mimotope sequences were also included for a broader representation. All of them were cloned and expressed in E.coli. The cross-reactivity of the purified recombinant HVR1 antigens was tested by ELISA with a panel of sera from HCV infected patients in China. Some of them were further ligated together to form a combinatorial HVR1 chimera. RESULTS Altogether 12 HVR1(s) were selected and expressed in E.coli and purified to homogeneity. All of these purified antigens showed some cross-reactivity with sera in a 27 HCV positive panel. Recombinant HVR1s of No. 1, 2, 4, and 8# showing broad cross-reactivities and complementarity with each other, were selected for the ligation elements. The chimera containing these 4 HVR1s was highly expressed in E.coli. The purified chimeric antigen could react not only with all the HCV antibody positive sera in the panel but also with 90/91 sera of HCV -infected patients. CONCLUSION The chimeric antigen was shown to have a broad cross-reactivity. It may be helpful for solving the problem caused by high variability of HCV, and in the efforts for a novel vaccine against the virus.
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Affiliation(s)
- Bing-Shui Xiu
- Laboratory of Molecular Virology, Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, P.R.China
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21
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Mondelli MU, Cerino A, Meola A, Nicosia A. Variability or conservation of hepatitis C virus hypervariable region 1? Implications for immune responses. J Biosci 2003; 28:305-10. [PMID: 12734408 DOI: 10.1007/bf02970149] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The hypervariable region 1 (HVR1) of the E2 protein of hepatitis C virus (HCV) is highly heterogeneous in its primary sequence and is responsible for significant inter- and intra-individual variation of the infecting virus, which may represent an important pathogenetic mechanism leading to immune escape and persistent infection. A binding site for neutralizing antibodies (Ab) has also been allegedly identified in this region. Prospective studies of serological responses to synthetic oligopeptides derived from naturally-occurring HVR1 sequences showed promiscuous recognition of HVR1 variants in most patients via binding to C-terminal amino acid residues with conserved physicochemical properties. Monoclonal antibodies generated by immunization of mice with peptides derived from natural HVR1 sequences were shown to recognize several HVR1 variants in line with evidence gathered from studies using human sera. In addition, selected mAbs were able to bind HVR1 in the context of a complete soluble form of the E2 glycoprotein, indicating recognition of correctly folded sequences, and were shown to specifically capture circulating and recombinant HCV particles, suggesting that HVR1 is expressed on intact virus particles and therefore potentially able to interact with cellular receptor(s). These findings suggest that it is possible to induce a broadly reactive clonal immune response to multiple HCV variants and that this mechanism could be used in principle to induce protective immunity for a large repertoire of HCV variants.
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Affiliation(s)
- Mario U Mondelli
- Dipartimento di Malattie Infettive, IRCCS Policlinico San Matteo, and University of Pavia, Via Taramelli 5, 27100 Pavia, Italy.
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22
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Affiliation(s)
- Xavier Forns
- Liver Unit, Institut de Malalties Digestives, Hospital Clínic, Villaroel 170, Barcelona 08036, Spain.
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23
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Zhou YH, Takekoshi M, Maeda F, Ihara S, Esumi M. Recombinant antibody Fab against the hypervariable region 1 of hepatitis C virus blocks the virus adsorption to susceptible cells in vitro. Antiviral Res 2002; 56:51-9. [PMID: 12323399 DOI: 10.1016/s0166-3542(02)00092-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Antibodies against hypervariable region 1 (HVR1) of hepatitis C virus (HCV) are putatively considered to be neutralizing. We previously found that monoclonal antibodies (mAbs) (30F1 and 30F3) against the HVR1 of HCV neutralize HCV in vitro. To develop potentially therapeutic molecules against HCV, we cloned cDNAs of antibody Fab fragments from the mouse hybridoma cells secreting these two mAbs. Fab fragments produced in Escherichia coli were purified by a single step of nickel-chelate affinity chromatography via a hexa-histidine tag. The specificity of the Fabs was confirmed by competition ELISA, BIAcore analysis, and N-terminal amino acid sequencing. The binding constant for the interaction with HVR1 was 1.39 nM for Fab 30F1 and 3.96 nM for Fab 30F3. The HCV capture assay and inhibition of HCV adsorption test demonstrated that both Fabs had neutralizing activity. The data may be useful for designing immunological therapy of HCV.
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Affiliation(s)
- Yi-Hua Zhou
- Department of Pathology, Nihon University School of Medicine, 30-1, Ooyaguchikami-machi, Itabashi-ku, Tokyo 173-8610, Japan
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Scarselli E, Ansuini H, Cerino R, Roccasecca RM, Acali S, Filocamo G, Traboni C, Nicosia A, Cortese R, Vitelli A. The human scavenger receptor class B type I is a novel candidate receptor for the hepatitis C virus. EMBO J 2002; 21:5017-25. [PMID: 12356718 PMCID: PMC129051 DOI: 10.1093/emboj/cdf529] [Citation(s) in RCA: 868] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We discovered that the hepatitis C virus (HCV) envelope glycoprotein E2 binds to human hepatoma cell lines independently of the previously proposed HCV receptor CD81. Comparative binding studies using recombinant E2 from the most prevalent 1a and 1b genotypes revealed that E2 recognition by hepatoma cells is independent from the viral isolate, while E2-CD81 interaction is isolate specific. Binding of soluble E2 to human hepatoma cells was impaired by deletion of the hypervariable region 1 (HVR1), but the wild-type phenotype was recovered by introducing a compensatory mutation reported previously to rescue infectivity of an HVR1-deleted HCV infectious clone. We have identified the receptor responsible for E2 binding to human hepatic cells as the human scavenger receptor class B type I (SR-BI). E2-SR-BI interaction is very selective since neither mouse SR-BI nor the closely related human scavenger receptor CD36, were able to bind E2. Finally, E2 recognition by SR-BI was competed out in an isolate-specific manner both on the hepatoma cell line and on the human SR-BI-transfected cell line by an anti-HVR1 monoclonal antibody.
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MESH Headings
- Animals
- Antigens, CD/physiology
- CD36 Antigens/physiology
- CHO Cells
- Carcinoma, Hepatocellular
- Cloning, Molecular
- Cricetinae
- Flow Cytometry
- Hepacivirus/physiology
- Humans
- Leukemia, T-Cell
- Liver Neoplasms
- Membrane Proteins/physiology
- Receptors, Immunologic
- Receptors, Lipoprotein/physiology
- Receptors, Scavenger
- Receptors, Virus/physiology
- Recombinant Proteins/metabolism
- Scavenger Receptors, Class B
- Tetraspanin 28
- Tumor Cells, Cultured
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Affiliation(s)
- Elisa Scarselli
- Istituto di Ricerche di Biologia Molecolare P.Angeletti (IRBM), Via Pontina Km 30.600, 00040 Pomezia (Roma), Italy
Present address: Department of Biochemistry, 414 Wartik Laboratory, Pennsylvania State University, University Park, PA 16802, USA Corresponding author e-mail:
| | | | | | - Rosa Maria Roccasecca
- Istituto di Ricerche di Biologia Molecolare P.Angeletti (IRBM), Via Pontina Km 30.600, 00040 Pomezia (Roma), Italy
Present address: Department of Biochemistry, 414 Wartik Laboratory, Pennsylvania State University, University Park, PA 16802, USA Corresponding author e-mail:
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Peng XX, Wang SY, Zhang JY, Zhu H. Analysis of HCV-immunoglobulin isotype complexes provide new insights into antibody response to HCV. Scand J Immunol 2002; 56:94-100. [PMID: 12100476 DOI: 10.1046/j.1365-3083.2002.01112.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Hepatitis C virus (HCV) is known for its ability to establish persistent infection and cause chronic hepatitis in most infected individuals. The antibody response to HCV in HCV-circulating immune complexes (CIC) is unknown. In the present study, we have characterized distinct changes in patterns of HCV-immunoglobulin (Ig) constituents with disease category, viral mutation and clinical markers. The number of samples positive for single HCV-Ig, HCV-IgG and HCV-IgA, HCV-IgM and HCV-IgA, HCV-IgM and HCV-IgG, HCV-IgM, HCV-IgG and HCV-IgA in 47 samples tested were 8 (17%), 1 (2.1%), 9 (19.1%), 4 (8.5%) and 17 (36.2%), respectively. The occurrence of HCV-IgM and HCV-IgA in combination of two isotypes of HCV-Ig became predominant. These results show that defective IgG in HCV-CIC may contribute to long-term viremia. Further analysis indicated that the frequency of HCV RNA/IgA-CIC in the abnormal aspartic aminotransferase (AST) group was significantly higher than that of the normal AST group, and HCV RNA/IgA-CIC frequency in the abnormal alanine aminotransferase (ALT) group was slightly higher than that in the normal ALT group. IgA complexes may reflect the damage degree of liver function during the course of HCV infection. We also found that there were more mutations in supernatant than in other constituents from single-strand conformation polymorphism (SSCP) analysis. Our results suggest that Ig-complexed virions and free virions may have different biological consequences, with the latter being elusive to immunological elimination. The findings in this study may provide some new insights into antibody response to HCV.
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Affiliation(s)
- X X Peng
- The Key Laboratory of Education Ministry for Cell Biology and Tumor Cell Engineering, Department of Biology, School of Life Sciences, Xiamen University, Fujian, P. R. China.
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Triyatni M, Vergalla J, Davis AR, Hadlock KG, Foung SKH, Liang TJ. Structural features of envelope proteins on hepatitis C virus-like particles as determined by anti-envelope monoclonal antibodies and CD81 binding. Virology 2002; 298:124-32. [PMID: 12093180 DOI: 10.1006/viro.2002.1463] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The envelope glycoprotein E2 of hepatitis C virus (HCV) is a major component of the viral envelope. Knowledge of its topologic features and antigenic determinants in virions is crucial in understanding the viral binding sites to cellular receptor(s) and the induction of neutralizing antibodies. The lack of a robust cell culture system for virus propagation has hampered the characterization of E2 presented on the virion. Here we report the structural features of hepatitis C virus-like particles (HCV-LPs) of the 1a and 1b genotypes as determined by various mouse and human monoclonal anti-envelope antibodies. Our results show that the E2 protein of HCV-LPs reacts with human monoclonal antibodies recognizing conformational determinants. Monoclonal antibodies (mAbs) specific for the hypervariable region 1 (HVR-1) sequence reacted strongly with HCV-LPs, suggesting that the HVR-1 is exposed on the viral surface. Several mAbs recognized both HCV-LPs with equally high affinity, indicating that the corresponding epitopes [amino acids (aa) 192-217 of E1 and aa 412-423, aa 522-531, and aa 640-653 of E2] are conserved in both genotypes and exposed on the surface of the HCV-LP. The E2 and E1/E2 dimers of 1a bound strongly to the recombinant large extracellular loop (LEL) of CD81 (CD81-LEL) of human and African green monkey, while the HCV-LP of 1a bound weakly to human CD81-LEL. E1/E2 dimers and the HCV-LPs of 1b did not bind CD81-LEL, consistent with the notion that CD81 recognition by E2 is strain-specific and does not correlate with permissiveness of infection. A model of the topology and exposed antigenic determinants of the envelope proteins of HCV is proposed.
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Affiliation(s)
- Miriam Triyatni
- Liver Diseases Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
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