scholarly journals Natural Killer Cell Function and Dysfunction in Hepatitis C Virus Infection

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Kayla A. Holder ◽  
Rodney S. Russell ◽  
Michael D. Grant
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Natural Killer ◽  
Nk Cell ◽  
Hcv Infection ◽  
Host Immune System ◽  
Chronic Hcv Infection ◽  
Chronic Hcv

Viruses must continually adapt against dynamic innate and adaptive responses of the host immune system to establish chronic infection. Only a small minority (~20%) of those exposed to hepatitis C virus (HCV) spontaneously clear infection, leaving approximately 200 million people worldwide chronically infected with HCV. A number of recent research studies suggest that establishment and maintenance of chronic HCV infection involve natural killer (NK) cell dysfunction. This relationship is illustratedin vitroby disruption of typical NK cell responses including both cell-mediated cytotoxicity and cytokine production. Expression of a number of activating NK cell receptorsin vivois also affected in chronic HCV infection. Thus, directin vivoandin vitroevidence of compromised NK function in chronic HCV infection in conjunction with significant epidemiological associations between the outcome of HCV infection and certain combinations of NK cell regulatory receptor and class I human histocompatibility linked antigen (HLA) genotypes indicate that NK cells are important in the immune response against HCV infection. In this review, we highlight evidence suggesting that selective impairment of NK cell activity is related to establishment of chronic HCV infection.

scholarly journals Clinical Significance of In Vitro Replication–Enhancing Mutations of the Hepatitis C Virus (HCV) Replicon in Patients with Chronic HCV Infection

2005 ◽  
Vol 192 (10) ◽  
pp. 1710-1719 ◽  
Author(s):  
Christoph Sarrazin ◽  
Ulrike Mihm ◽  
Eva Herrmann ◽  
Christoph Welsch ◽  
Mario Albrecht ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Clinical Significance ◽  
Hcv Infection ◽  
In Vitro Replication ◽  
Chronic Hcv Infection ◽  
Chronic Hcv

scholarly journals Characterization of Resistance to the Nonnucleoside NS5B Inhibitor Filibuvir in Hepatitis C Virus-Infected Patients

2011 ◽  
Vol 56 (3) ◽  
pp. 1331-1341 ◽  
Author(s):  
Philip J. F. Troke ◽  
Marilyn Lewis ◽  
Paul Simpson ◽  
Katrina Gore ◽  
Jennifer Hammond ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Amino Acid ◽  
Site Directed Mutagenesis ◽  
Phenotypic Resistance ◽  
Number Of Patients ◽  
Chronic Hcv ◽  
Selection Of

ABSTRACTFilibuvir (PF-00868554) is an investigational nonnucleoside inhibitor of the hepatitis C virus (HCV) nonstructural 5B (NS5B) RNA-dependent RNA polymerase currently in development for treating chronic HCV infection. The aim of this study was to characterize the selection of filibuvir-resistant variants in HCV-infected individuals receiving filibuvir as short (3- to 10-day) monotherapy. We identified amino acid M423 as the primary site of mutation arising upon filibuvir dosing. Through bulk cloning of clinical NS5B sequences into a transient-replicon system, and supported by site-directed mutagenesis of the Con1 replicon, we confirmed that mutations M423I/T/V mediate phenotypic resistance. Selection in patients of an NS5B mutation at M423 was associated with a reduced replicative capacityin vitrorelative to the pretherapy sequence; consistent with this, reversion to wild-type M423 was observed in the majority of patients following therapy cessation. Mutations at NS5B residues R422 and M426 were detected in a small number of patients at baseline or the end of therapy and also mediate reductions in filibuvir susceptibility, suggesting these are rare but clinically relevant alternative resistance pathways. Amino acid variants at position M423 in HCV NS5B polymerase are the preferred pathway for selection of viral resistance to filibuvirin vivo.

Circulating and inducible IL-32α in chronic hepatitis C virus infection

2019 ◽  
Vol 2 (1) ◽  
pp. 23-30
Author(s):  
Mark Collister ◽  
Julia Rempel ◽  
Jiaqi Yang ◽  
Kelly Kaita ◽  
Zach Raizman ◽  
...  
Keyword(s):  
Chronic Hepatitis ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Chronic Hepatitis C ◽  
Mononuclear Cells ◽  
Peripheral Blood Mononuclear ◽  
Chronic Hepatitis C Virus ◽  
Chronic Hcv

Background: Interleukin 32 (IL-32) is a recently described pro-inflammatory cytokine implicated in chronic hepatitis C virus (HCV)-related inflammation and fibrosis. IL-32α is the most abundant IL-32 isoform. Methods: Circulating IL-32α levels were documented in patients with chronic HCV infections ( n = 31) and compared with individuals who spontaneously resolved HCV infection ( n = 14) and HCV-naive controls ( n = 20). In addition, peripheral blood mononuclear cells (PBMC) from the chronic HCV ( n = 12) and HCV-naive ( n = 9) cohorts were investigated for responses to HCV core and non-structural (NS)3 protein induced IL-32α production. Finally, correlations between IL-32α levels, hepatic fibrosis and subsequent responses to interferon-based therapy were documented in patients with chronic HCV. Results: Circulating IL-32α levels in patients with chronic HCV were similar to those of spontaneously resolved and HCV-naive controls. HCV protein induced IL-32α responses were similar in chronic HCV patients and HCV-naive controls. In patients with chronic HCV, serum IL-32α levels correlated with worsening METAVIR fibrosis (F) scores from F0 to F3 ( r = 0.596, P < 0.001) as did NS3 induced IL-32α responses ( r = 0.837, P < 0.05). However, these correlations were not sustained with the inclusion of IL-32α levels at F4 scores, suggesting events at F4 interfere with IL-32α synthesis or release. In chronic HCV patients who underwent treatment ( n = 28), baseline in vivo and in vitro induced IL-32α concentrations were not predictive of therapeutic outcomes. Conclusions: IL-32α activity is associated with worsening fibrosis scores in non-cirrhotic, chronic HCV patients.

IgM and IgA antibodies generated against hepatitis C virus core antigen in patients with acute and chronic HCV infection

1994 ◽  
Vol 39 (9) ◽  
pp. 2022-2031 ◽  
Author(s):  
Shinjiro Sato ◽  
Shigetoshi Fujiyama ◽  
Motohiko Tanaka ◽  
Masafumi Goto ◽  
Yuko Taura ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hcv Infection ◽  
Core Antigen ◽  
Virus Core ◽  
Iga Antibodies ◽  
Chronic Hcv Infection ◽  
Chronic Hcv

scholarly journals Pharmacokinetics, Safety, and Antiviral Effects of Hypericin, a Derivative of St. John's Wort Plant, in Patients with Chronic Hepatitis C Virus Infection

2001 ◽  
Vol 45 (2) ◽  
pp. 517-524 ◽  
Author(s):  
Jeffrey M. Jacobson ◽  
Lawrence Feinman ◽  
Leonard Liebes ◽  
Nancy Ostrow ◽  
Victoria Koslowski ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Hcv Infection ◽  
Hcv Rna ◽  
Pharmacokinetic Data ◽  
Serious Adverse Events ◽  
Dosing Schedule ◽  
Diarrhea Virus ◽  
Chronic Hcv Infection ◽  
Chronic Hcv

ABSTRACT Hypericin is a natural derivative of the common St. Johns wort plant, Hypericum perforatum. It has in vitro activity against several viruses, including bovine diarrhea virus, a pestivirus with structural similarities to hepatitis C virus (HCV). We conducted a phase I dose escalation study to determine the safety and antiviral activity of hypericin in patients with chronic HCV infection. The first 12 patients received an 8-week course of 0.05 mg of hypericin per kg of body weight orally once a day; 7 patients received an 8-week course of 0.10 mg/kg orally once a day. At the end of the 8-week period of treatment, no subject had a change of plasma HCV RNA level of more than 1.0 log10. Five of 12 subjects receiving the 0.05-mg/kg/day dosing schedule and 6 of 7 subjects receiving the 0.10-mg/kg/day dosing schedule developed phototoxic reactions. No other serious adverse events associated with hypericin use occurred. The pharmacokinetic data revealed a long elimination half-life (mean values of 36.1 and 33.8 h, respectively, for the doses of 0.05 and 0.1 mg/kg) and mean area under the curve determinations of 1.5 and 3.1 μg/ml × hr, respectively. In sum, hypericin given orally in doses of 0.05 and 0.10 mg/kg/d caused considerable phototoxicity and had no detectable anti-HCV activity in patients with chronic HCV infection.

scholarly journals Replication of Hepatitis C Virus (HCV) RNA in Mouse Embryonic Fibroblasts: Protein Kinase R (PKR)-Dependent and PKR-Independent Mechanisms for Controlling HCV RNA Replication and Mediating Interferon Activities

2006 ◽  
Vol 80 (15) ◽  
pp. 7364-7374 ◽  
Author(s):  
Kyung-Soo Chang ◽  
Zhaohui Cai ◽  
Chen Zhang ◽  
Ganes C. Sen ◽  
Bryan R. G. Williams ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Replication ◽  
Hcv Infection ◽  
Hcv Rna ◽  
Protein Kinase R ◽  
Mouse Embryonic Fibroblasts ◽  
Embryonic Fibroblasts ◽  
Chronic Hcv Infection ◽  
Chronic Hcv

ABSTRACT Hepatitis C virus (HCV) infection causes chronic hepatitis and is currently treated with alpha interferon (IFN-α)-based therapies. The underlying mechanisms of chronic HCV infection and IFN-based therapies, however, have not been defined. Protein kinase R (PKR) was implicated in the control of HCV replication and mediation of IFN-induced antiviral response. In this report, we demonstrate that a subgenomic RNA replicon of genotype 2a HCV replicated efficiently in mouse embryonic fibroblasts (MEFs), as determined by cell colony formation efficiency and the detection of HCV proteins and both positive- and negative-strand RNAs. Additionally, the subgenomic HCV RNA was found to replicate more efficiently in the PKR knockout (PKR−/−) MEF than in the wild-type (PKR+/+) MEF. The knockdown expression of PKR by specific small interfering RNAs significantly enhanced the level of HCV RNA replication, suggesting that PKR is involved in the control of HCV RNA replication. The level of ISG56 (p56) was induced by HCV RNA replication, indicating the activation of PKR-independent antiviral pathways. Furthermore, IFN-α/β inhibited HCV RNA replication in PKR−/− MEFs as efficiently as in PKR+/+ MEFs. These findings demonstrate that PKR-independent antiviral pathways play important roles in controlling HCV replication and mediating IFN-induced antiviral effect. Our findings also provide a foundation for the development of transgenic mouse models of HCV replication and set a stage to further define the roles of cellular genes in the establishment of chronic HCV infection and the mediation of intracellular innate antiviral response by using MEFs derived from diverse gene knockout animals.

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