Hepatitis C Virus E2 Has Three Immunogenic Domains Containing Conformational Epitopes with Distinct Properties and Biological Functions

ABSTRACT Mechanisms of virion attachment, interaction with its receptor, and cell entry are poorly understood for hepatitis C virus (HCV) because of a lack of an efficient and reliable in vitro system for virus propagation. Infectious HCV retroviral pseudotype particles (HCVpp) were recently shown to express native E1E2 glycoproteins, as defined in part by HCV human monoclonal antibodies (HMAbs) to conformational epitopes on E2, and some of these antibodies block HCVpp infection (A. Op De Beeck, C. Voisset, B. Bartosch, Y. Ciczora, L. Cocquerel, Z. Y. Keck, S. Foung, F. L. Cosset, and J. Dubuisson, J. Virol. 78:2994-3002, 2004). Why some HMAbs are neutralizing and others are nonneutralizing is looked at in this report by a series of studies to determine the expression of their epitopes on E2 associated with HCVpp and the role of antibody binding affinity. Antibody cross-competition defined three E2 immunogenic domains with neutralizing HMAbs restricted to two domains that were also able to block E2 interaction with CD81, a putative receptor for HCV. HCVpp immunoprecipitation showed that neutralizing and nonneutralizing domains are expressed on E2 associated with HCVpp, and affinity studies found moderate-to-high-affinity antibodies in all domains. These findings support the perspective that HCV-specific epitopes are responsible for functional steps in virus infection, with specific antibodies blocking distinct steps of virus attachment and entry, rather than the perspective that virus neutralization correlates with increased antibody binding to any virion surface site, independent of the epitope recognized by the antibody. Segregation of virus neutralization and sensitivity to low pH to specific regions supports a model of HCV E2 immunogenic domains similar to the antigenic structural and functional domains of other flavivirus envelope E glycoproteins.

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Suggested role of the Golgi apparatus and endoplasmic reticulum for crucial sites of hepatitis C virus replication in human lymphoblastoid cells infected in vitro

Journal of Medical Virology ◽

10.1002/jmv.10367 ◽

2003 ◽

Vol 70 (1) ◽

pp. 31-41 ◽

Cited By ~ 18

Author(s):

Annalucia Serafino ◽

Maria Beatrice Valli ◽

Federica Andreola ◽

Annalisa Crema ◽

Giampietro Ravagnan ◽

...

Keyword(s):

Endoplasmic Reticulum ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Golgi Apparatus ◽

Virus Replication ◽

Lymphoblastoid Cells

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In Vivo and In Vitro Potency of Polyphosphazene Immunoadjuvants with Hepatitis C Virus Antigen and the Role of Their Supramolecular Assembly

Molecular Pharmaceutics ◽

10.1021/acs.molpharmaceut.0c00487 ◽

2020 ◽

Cited By ~ 1

Author(s):

Alexander K. Andrianov ◽

Alexander Marin ◽

Ruixue Wang ◽

Ananda Chowdhury ◽

Pragati Agnihotri ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Supramolecular Assembly ◽

Virus Antigen

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Modeling hepatitis C virus kinetics during liver transplantation highlights the role of the liver in virus clearance

10.1101/2020.08.03.20167387 ◽

2020 ◽

Author(s):

Louis Shekhtman ◽

Miquel Navasa ◽

Natasha Sansone ◽

Gonzalo Crespo ◽

Gitanjali Subramanya ◽

...

Keyword(s):

Cell Culture ◽

Liver Transplantation ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Clearance Rate ◽

Culture Medium ◽

Viral Clearance ◽

Huh7 Cells

AbstractWhile the liver, specifically hepatocytes, are widely accepted as the main source for hepatitis C virus (HCV) production, the role of the liver/hepatocytes in the clearance of circulating HCV remains largely unknown. Here we evaluated the function of the liver/hepatocytes in clearing virus from the circulation by investigating viral clearance during liver transplantation and from culture medium in vitro. Frequent HCV kinetic data during liver transplantation were recorded from 5 individuals throughout the anhepatic (AH) phase and for 4 hours after reperfusion (RP), along with recordings of fluid balances. Using mathematical modeling, the serum viral clearance rate, c, was estimated. Analogously, we monitored the clearance rate of HCV at 37°C from culture medium in vitro in the absence and presence of chronically infected Huh7 human hepatoma cells. During the AH phase, in 3 transplant cases viral levels remained at pre-AH levels, while in the other 2 cases HCV declined (half-life, t1/2~1h). Immediately post-RP, virus declined in a biphasic manner in Cases 1-4 consisting of an extremely rapid (median t1/2=5min) decline followed by a slower decline (HCV t1/2=67min). In Case 5, HCV remained at the same level post-RP as at the end of AH. Declines in virus level were not explained by adjusting for dilution from IV fluid and blood products. Consistent with what was observed in the majority of patients in the anhepatic phase, the t1/2 of HCV in cell culture was much longer in the absence of chronically HCV-infected Huh7 cells. Therefore, kinetic and modeling results from both in vivo liver transplantation cases and in vitro cell culture studies suggest that the liver plays a major role in clearing HCV from the circulation.

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In vitro selection of RNA aptamers that bind the RNA-dependent RNA polymerase of hepatitis C virus: A possible role of GC-rich RNA motifs in NS5B binding

Virology ◽

10.1016/j.virol.2009.02.032 ◽

2009 ◽

Vol 388 (1) ◽

pp. 91-102 ◽

Cited By ~ 5

Author(s):

Hiroshi Kanamori ◽

Kazuhito Yuhashi ◽

Yasutoshi Uchiyama ◽

Tatsuhiko Kodama ◽

Shin Ohnishi

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Rna Polymerase ◽

In Vitro Selection ◽

Rna Aptamers ◽

Rna Dependent Rna Polymerase ◽

Rna Motifs ◽

Selection Of

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Role of molecular mimicry of hepatitis C virus protein with platelet GPIIIa in hepatitis C–related immunologic thrombocytopenia

Blood ◽

10.1182/blood-2008-09-181073 ◽

2009 ◽

Vol 113 (17) ◽

pp. 4086-4093 ◽

Cited By ~ 77

Author(s):

Wei Zhang ◽

Michael A. Nardi ◽

William Borkowsky ◽

Zongdong Li ◽

Simon Karpatkin

Keyword(s):

Platelet Count ◽

Hepatitis C Virus ◽

Hepatitis C ◽

Molecular Mimicry ◽

Virus Protein ◽

Drug Abusers ◽

Phage Peptide Library ◽

Hiv 1

Abstract Patients with HIV-1 immune-related thrombocytopenia (HIV-1–ITP) have a unique Ab against platelet GPIIIa49-66 capable of inducing oxidative platelet fragmentation in the absence of complement. HIV-1–seropositive drug abusers are more prone to develop immune thrombocytopenia than non–drug abusers and have a higher coinfection with hepatitis C virus (HCV) than non–drug abusers (90% vs 30%). Molecular mimicry was sought by screening a phage peptide library with anti–GPIIIa49-66 antibody as bait for peptides sharing homology sequences with HCV. Several phage peptide clones had 70% homology with HCV protein. Sera from dually infected thrombocytopenic patients with HCV and HIV-ITP reacted strongly with 4 nonconserved peptides from HCV core envelope 1. Reactivity correlated inversely with platelet count (r2 = 0.7, P < .01). Ab raised against peptide PHC09 in GPIIIa−/− mice induced thrombocytopenia in wild-type mice. Affinity-purified IgG against PHC09 induced oxidative platelet fragmentation in vitro. Drug abusers dually infected with HCV and HIV-1 had a greater incidence and severity of thrombocytopenia as well as titer of anti–GPIIIa49-66/PHC09 Ab. NZB/W F1 mice injected with recombinant core envelope 1 developed Ab versus PHC09 and significantly decreased their platelet count (P < .001). Thus, HCV core envelope 1 can induce thrombocytopenia by molecular mimicry with GPIIIa49-66.

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Anti-Hepatitis C Virus Activity and Toxicity of Type III Phosphatidylinositol-4-Kinase Beta Inhibitors

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00946-12 ◽

2012 ◽

Vol 56 (10) ◽

pp. 5149-5156 ◽

Cited By ~ 44

Author(s):

M. J. LaMarche ◽

J. Borawski ◽

A. Bose ◽

C. Capacci-Daniel ◽

R. Colvin ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Cellular Targets ◽

Type Iii ◽

Genotype 1A ◽

Cellular Target ◽

Phosphatidylinositol 4 ◽

Interfering Rna

ABSTRACTType III phosphatidylinositol-4-kinase beta (PI4KIIIβ) was previously implicated in hepatitis C virus (HCV) replication by small interfering RNA (siRNA) depletion and was therefore proposed as a novel cellular target for the treatment of hepatitis C. Medicinal chemistry efforts identified highly selective PI4KIIIβ inhibitors that potently inhibited the replication of genotype 1a and 1b HCV replicons and genotype 2a virusin vitro. Replicon cells required more than 5 weeks to reach low levels of 3- to 5-fold resistance, suggesting a high resistance barrier to these cellular targets. Extensivein vitroprofiling of the compounds revealed a role of PI4KIIIβ in lymphocyte proliferation. Previously proposed functions of PI4KIIIβ in insulin secretion and the regulation of several ion channels were not perturbed with these inhibitors. Moreover, PI4KIIIβ inhibitors were not generally cytotoxic as demonstrated across hundreds of cell lines and primary cells. However, an unexpected antiproliferative effect in lymphocytes precluded their further development for the treatment of hepatitis C.

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Metabolic Activation of the Anti-Hepatitis C Virus Nucleotide Prodrug PSI-352938

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00530-12 ◽

2012 ◽

Vol 56 (7) ◽

pp. 3767-3775 ◽

Cited By ~ 18

Author(s):

Congrong Niu ◽

Tatiana Tolstykh ◽

Haiying Bao ◽

Yeojin Park ◽

Darius Babusis ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Nucleoside Diphosphate Kinase ◽

Metabolic Activation ◽

Primary Hepatocytes ◽

Biochemical Assays ◽

Cyclic Phosphate ◽

Cyp Isoforms

ABSTRACTPSI-352938 is a novel cyclic phosphate prodrug of β-d-2′-deoxy-2′-α-fluoro-2′-β-C-methylguanosine-5′-monophosphate with potent anti-HCV activity. In order to inhibit the NS5B RNA-dependent RNA polymerase, PSI-352938 must be metabolized to the active triphosphate form, PSI-352666. Duringin vitroincubations with PSI-352938, significantly larger amounts of PSI-352666 were formed in primary hepatocytes than in clone A hepatitis C virus (HCV) replicon cells. Metabolism and biochemical assays were performed to define the molecular mechanism of PSI-352938 activation. The first step, removal of the isopropyl group on the 3′,5′-cyclic phosphate moiety, was found to be cytochrome P450 (CYP) 3A4 dependent, with other CYP isoforms unable to catalyze the reaction. The second step, opening of the cyclic phosphate ring, was catalyzed by phosphodiesterases (PDEs) 2A1, 5A, 9A, and 11A4, all known to be expressed in the liver. The role of these enzymes in the activation of PSI-352938 was confirmed in primary human hepatocytes, where prodrug activation was reduced by inhibitors of CYP3A4 and PDEs. The third step, removal of theO6-ethyl group on the nucleobase, was shown to be catalyzed by adenosine deaminase-like protein 1. The resulting monophosphate was consecutively phosphorylated to the diphosphate and to the triphosphate PSI-352666 by guanylate kinase 1 and nucleoside diphosphate kinase, respectively. In addition, formation of nucleoside metabolites was observed in primary hepatocytes, and ecto-5′-nucleotidase was able to dephosphorylate the monophosphate metabolites. Since CYP3A4 is highly expressed in the liver, the CYP3A4-dependent metabolism of PSI-352938 makes it an effective liver-targeted prodrug, in part accounting for the potent antiviral activity observed clinically.

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