scholarly journals Adaptive Immune Response against Hepatitis C Virus

2020 ◽  
Vol 21 (16) ◽  
pp. 5644
Author(s):  
Janine Kemming ◽  
Robert Thimme ◽  
Christoph Neumann-Haefelin
Keyword(s):  
Immune Response ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Persistent Infection ◽  
Adaptive Immune Response ◽  
Hcv Infection ◽  
Viral Escape ◽  
Continuous Exposure ◽  
Adaptive Immune ◽  
Adaptive Immune Cells

A functional adaptive immune response is the major determinant for clearance of hepatitis C virus (HCV) infection. However, in the majority of patients, this response fails and persistent infection evolves. Here, we dissect the HCV-specific key players of adaptive immunity, namely B cells and T cells, and describe factors that affect infection outcome. Once chronic infection is established, continuous exposure to HCV antigens affects functionality, phenotype, transcriptional program, metabolism, and the epigenetics of the adaptive immune cells. In addition, viral escape mutations contribute to the failure of adaptive antiviral immunity. Direct-acting antivirals (DAA) can mediate HCV clearance in almost all patients with chronic HCV infection, however, defects in adaptive immune cell populations remain, only limited functional memory is obtained and reinfection of cured individuals is possible. Thus, to avoid potential reinfection and achieve global elimination of HCV infections, a prophylactic vaccine is needed. Recent vaccine trials could induce HCV-specific immunity but failed to protect from persistent infection. Thus, lessons from natural protection from persistent infection, DAA-mediated cure, and non-protective vaccination trials might lead the way to successful vaccination strategies in the future.

Acute infection with a single hepatitis C virus strain in dialysis patients: Analysis of adaptive immune response and viral variability

2009 ◽  
Vol 50 (4) ◽  
pp. 693-704 ◽  
Author(s):  
Lukas Weseslindtner ◽  
Christoph Neumann-Haefelin ◽  
Sergei Viazov ◽  
Anita Haberstroh ◽  
Josef Kletzmayr ◽  
...  
Keyword(s):  
Immune Response ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Strain ◽  
Acute Infection ◽  
Adaptive Immune Response ◽  
Dialysis Patients ◽  
Adaptive Immune

scholarly journals Hepatitis C virus enhances Rubicon expression, leading to autophagy inhibition and intracellular innate immune activation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yuto Shiode ◽  
Hayato Hikita ◽  
Satoshi Tanaka ◽  
Kumiko Shirai ◽  
Akira Doi ◽  
...  
Keyword(s):  
Immune Response ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Late Stage ◽  
Early Stage ◽  
Hcv Infection ◽  
Infected Cells ◽  
The Impact ◽  
Chronic Hepatitis C Patients

Abstract Autophagy, a degradation system, works to maintain cellular homeostasis. However, as the impact of Hepatitis C virus (HCV) infection on hepatocyte autophagy and its effect on HCV replication remain unclear, we examined them. HCV infection suppressed late-stage autophagy and increased Rubicon. siRNA-mediated knockdown of Rubicon promoted autophagy in HCV-infected cells. In Huh-7 cells harbouring the HCV replicon, Rubicon knockdown downregulated the expression of type 1 interferon (IFN)-related genes and upregulated HCV replication. Rubicon overexpression or administration of bafilomycin A1 or chloroquine, an inhibitor of late-stage autophagy, suppressed autophagy and activated the type 1 IFN pathway. On the other hand, Atg7 knockout suppressed early-stage autophagy and did not activate the type 1 IFN pathway. In livers of humanized liver chimeric mice, HCV infection increased Rubicon and enhanced type 1 IFN signalling. Elimination of HCV in the mice reduced the increase in Rubicon due to HCV infection. The expression levels of Rubicon and IFN-stimulated genes in chronic hepatitis C patients were higher than those in non-B, non-C hepatitis patients. HCV infection increased Rubicon and suppressed hepatocyte autophagy, leading to activation of the intracellular immune response. Rubicon induction is involved in HCV replication via activation of the intracellular immune response.

scholarly journals Priming of Antiviral CD8 T Cells without Effector Function by a Persistently Replicating Hepatitis C-Like Virus

2020 ◽  
Vol 94 (10) ◽  
Author(s):  
Alex S. Hartlage ◽  
Christopher M. Walker ◽  
Amit Kapoor
Keyword(s):  
T Cells ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
T Cell ◽  
Animal Models ◽  
Cd8 T Cells ◽  
Persistent Infection ◽  
Cd8 T Cell ◽  
Effector Function ◽  
Viral Escape

ABSTRACT Immune-competent animal models for the hepatitis C virus (HCV) are nonexistent, impeding studies of host-virus interactions and vaccine development. Experimental infection of laboratory rats with a rodent hepacivirus isolated from Rattus norvegicus (RHV) is a promising surrogate model due to its recapitulation of HCV-like chronicity. However, several aspects of rat RHV infection remain unclear, for instance, how RHV evades host adaptive immunity to establish persistent infection. Here, we analyzed the induction, differentiation, and functionality of RHV-specific CD8 T cell responses that are essential for protection against viral persistence. Virus-specific CD8 T cells targeting dominant and subdominant major histocompatibility complex class I epitopes proliferated considerably in liver after RHV infection. These populations endured long term yet never acquired antiviral effector functions or selected for viral escape mutations. This was accompanied by the persistent upregulation of programmed cell death-1 and absent memory cell formation, consistent with a dysfunctional phenotype. Remarkably, transient suppression of RHV viremia with a direct-acting antiviral led to the priming of CD8 T cells with partial effector function, driving the selection of a viral escape variant. These data demonstrate an intrinsic abnormality within CD8 T cells primed by rat RHV infection, an effect that is governed at least partially by the magnitude of early virus replication. Thus, this model could be useful in investigating mechanisms of CD8 T cell subversion, leading to the persistence of hepatotropic pathogens such as HCV. IMPORTANCE Development of vaccines against hepatitis C virus (HCV), a major cause of cirrhosis and cancer, has been stymied by a lack of animal models. The recent discovery of an HCV-like rodent hepacivirus (RHV) enabled the development of such a model in rats. This platform recapitulates HCV hepatotropism and viral chronicity necessary for vaccine testing. Currently, there are few descriptions of RHV-specific responses and why they fail to prevent persistent infection in this model. Here, we show that RHV-specific CD8 T cells, while induced early at high magnitude, do not develop into functional effectors capable of controlling virus. This defect was partially alleviated by short-term treatment with an HCV antiviral. Thus, like HCV, RHV triggers dysfunction of virus-specific CD8 T cells that are vital for infection resolution. Additional study of this evasion strategy and how to mitigate it could enhance our understanding of hepatotropic viral infections and lead to improved vaccines and therapeutics.

scholarly journals Hepatitis C Virus Attenuates Mitochondrial Lipid β-Oxidation by Downregulating Mitochondrial Trifunctional-Protein Expression

2015 ◽  
Vol 89 (8) ◽  
pp. 4092-4101 ◽  
Author(s):  
Yutaka Amako ◽  
Tsubasa Munakata ◽  
Michinori Kohara ◽  
Aleem Siddiqui ◽  
Chris Peers ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Persistent Infection ◽  
Liver Steatosis ◽  
Hcv Infection ◽  
Host Cells ◽  
Type I ◽  
Mrna Levels ◽  
Mitochondrial Lipid ◽  
Mitochondrial Trifunctional Protein

ABSTRACTThe course of hepatitis C virus (HCV) infection and disease progression involves alterations in lipid metabolism, leading to symptoms such as hypocholesterolemia and steatosis. Steatosis can be induced by multiple mechanisms, including increases in lipid biosynthesis and uptake, impaired lipoprotein secretion, and/or attenuation of lipid β-oxidation. However, little is known about the effects of HCV on lipid β-oxidation. A previous proteomics study revealed that HCV interacted with both the α- and β-subunits of the mitochondrial trifunctional protein (MTP), an enzyme complex which catalyzes the last 3 steps of mitochondrial lipid β-oxidation for cellular energy production. Here we show that in HCV-infected Huh7.5 cells, lipid β-oxidation was significantly attenuated. Consistently with this, MTP protein and mRNA levels were suppressed by HCV infection. A loss-of-function study showed that MTP depletion rendered cells less responsive to alpha interferon (IFN-α) treatment by impairing IFN-stimulated gene expression. These aspects of host-virus interaction explain how HCV alters host energy homeostasis and how it may also contribute to the establishment of persistent infection in the liver.IMPORTANCEHCV infection triggers metabolic alterations, which lead to significant disease outcomes, such as fatty liver (steatosis). This study revealed that HCV impairs mitochondrial lipid β-oxidation, which results in low lipid combustion. On the other hand, the HCV-induced defects in metabolic status played an important role in the control of the type I interferon system. Under the conditions of impaired lipid β-oxidation, host cells were less responsive to the ability of exogenously added IFN-α to suppress HCV replication. This suggests that interference with lipid β-oxidation may assist the virus in the establishment of a long-term, persistent infection. Further understanding of this aspect of virus-host interaction may lead to improvements in the current standard therapy.

[457] HCV INFECTION OF DENDRITIC CELLS AFFECTS THEIR FUNCTION LEADING TO AN IMPAIRED ADAPTIVE IMMUNE RESPONSE

2007 ◽  
Vol 46 ◽  
pp. S174
Author(s):  
I. Pachiadakis ◽  
S. Choksi ◽  
H. Cooksley ◽  
C. Sarrazzin ◽  
S. Zeuzem ◽  
...  
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Adaptive Immune Response ◽  
Hcv Infection ◽  
Adaptive Immune

scholarly journals Control of Heterologous Hepatitis C Virus Infection in Chimpanzees Is Associated with the Quality of Vaccine-Induced Peripheral T-Helper Immune Response

2004 ◽  
Vol 78 (1) ◽  
pp. 187-196 ◽  
Author(s):  
C. Rollier ◽  
E. Depla ◽  
J. A. R. Drexhage ◽  
E. J. Verschoor ◽  
B. E. Verstrepen ◽  
...  
Keyword(s):  
Immune Response ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Interleukin 2 ◽  
Hcv Infection ◽  
T Helper ◽  
Vaccine Strategy ◽  
Ns3 Protein ◽  
Ifn Γ

ABSTRACT Prophylactic hepatitis C virus (HCV) vaccine trials with human volunteers are pending. There is an important need for immunological end points which correlate with vaccine efficacy and which do not involve invasive procedures, such as liver biopsies. By using a multicomponent DNA priming-protein boosting vaccine strategy, naïve chimpanzees were immunized against HCV structural proteins (core, E1, and E2) as well as a nonstructural (NS3) protein. Following immunization, exposure to the heterologous HCV 1b J4 subtype resulted in a peak of plasma viremia which was lower in both immunized animals. Compared to the naïve infection control and nine additional historical controls which became chronic, vaccinee 2 (Vac2) rapidly resolved the infection, while the other (Vac1) clearly controlled HCV infection. Immunization induced antibodies, peptide-specific gamma interferon (IFN-γ), protein-specific lymphoproliferative responses, IFN-γ, interleukin-2 (IL-2), and IL-4 T-helper responses in both vaccinees. However, the specificities were markedly different: Vac2 developed responses which were lower in magnitude than those of Vac1 but which were biased towards Th1-type cytokine responses for E1 and NS3. This proof-of-principle study in chimpanzees revealed that immunization with a combination of nonstructural and structural antigens elicited T-cell responses associated with an alteration of the course of infection. Our findings provide data to support the concept that the quality of the response to conserved epitopes and the specific nature of the peripheral T-helper immune response are likely pivotal factors influencing the control and clearance of HCV infection.

scholarly journals Antiviral and Immunoregulatory Effects of Indoleamine-2,3-Dioxygenase in Hepatitis C Virus Infection

2015 ◽  
Vol 7 (5) ◽  
pp. 530-544 ◽  
Author(s):  
Quentin Lepiller ◽  
Eric Soulier ◽  
Qisheng Li ◽  
Mélanie Lambotin ◽  
Jochen Barths ◽  
...  
Keyword(s):  
Immune Response ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Inhibitory Effect ◽  
Hcv Infection ◽  
Antiviral Immune Response ◽  
Host Immune Responses ◽  
Indoleamine 2,3 Dioxygenase ◽  
Important Regulator ◽  
Innate Defence

In patients with hepatitis C virus (HCV) infection, enhanced activity of indoleamine-2,3-dioxygenase 1 (IDO) has been reported. IDO - a tryptophan-catabolizing enzyme - has been considered as both an innate defence mechanism and an important regulator of the immune response. The molecular mechanism of IDO induction in HCV infection and its role in the antiviral immune response remain unknown. Using primary human hepatocytes, we show that HCV infection stimulates IDO expression. IDO gene induction was transient and coincided with the expression of types I and III interferons (IFNs) and IFN-stimulated genes in HCV-infected hepatocytes. Overexpression of hepatic IDO prior to HCV infection markedly impaired HCV replication in hepatocytes, suggesting that IDO limits the spread of HCV within the liver. siRNA-mediated IDO knock-down revealed that IDO functions as an IFN-mediated anti-HCV effector. Hepatic IDO was most potently induced by IFN-γ, and ongoing HCV replication could significantly upregulate IDO expression. IRF1 (IFN-regulatory factor 1) and STAT1 (signal transducer and activator of transcription 1) regulated hepatic IDO expression. Hepatic IDO expression also had a significant inhibitory effect on CD4+ T-cell proliferation. Our data suggest that hepatic IDO plays a dual role during HCV infection by slowing down viral replication and also regulating host immune responses.

Sign in / Sign up

Export Citation Format

Share Document