Susceptibility of different hepatitis B virus isolates to interferon-alpha in a mouse model based on hydrodynamic injection.

Jingjiao Song,Jun Wu,Baoju Wang,Sheng Li,Kathrin Gibbert,Dongliang Yang,Ulf Dittmer,Mengji Lu,Yun Zhou,Xin Zheng,Wang-Shick Ryu

doi:10.1371/journal.pone.0090977

Jingjiao Song, Jun Wu + Show 9 more

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https://doi.org/10.1371/journal.pone.0090977

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Abstract

Interferon alpha (IFN-α) is commonly used for the treatment of chronic hepatitis B (CHB) patients. Many factors including viral genetics may determine the outcome of IFN-α therapy. In this study, we tested whether the expression of IFN-α directly in the liver inhibits HBV gene expression and replication using a HBV hydrodynamic injection (HI) mouse model. Two replication-competent clones from different HBV isolates that belonging to HBV genotype A and B based on a pAAV vector (pAAV-HBV-A and pAAV-HBV-B) were compared for their susceptibility to IFN-α. HBV clones were injected into mice either alone or in combination with a murine (m) IFN-α expression plasmid (pmIFN-α). HBsAg and HBeAg concentrations and HBV DNA levels in mice differed after injection of these two HBV clones. Co-application of pmIFN-α together with the two distinct isolates resulted in markedly different kinetics of decline of HBsAg, HBeAg, and HBV DNA levels in the mice. Immunohistochemical staining of liver sections with anti-HBc showed that mIFN-α application completely inhibited the expression of HBcAg in mice inoculated with pAAV-HBV-B, whereas the expression of HBcAg was only reduced in mice with pAAV-HBV-A. Consistently, mice injected with pAAV-HBV-B and pmIFN-α showed higher expression levels of the IFN-stimulated genes (ISGs) ISG15, OAS, PKR as well as proinflammatory cytokine IL-6 in the liver. In addition, expression levels of anti-inflammatory cytokine IL-10 was down-regulated significantly in liver of the mice injected with pAAV-HBV-B and pmIFN-α. Our data demonstrate that IFN-α exerts antiviral activity in HBV mouse model, but different HBV isolates may have diverse susceptibility to IFN-α.

Highlights

Hepatitis B virus (HBV) is a DNA virus causing chronic infections of the human liver [1]
Identification of pAAV-HBV-B To compare the susceptibility of different HBV isolates to IFN-a in the hydrodynamic injection (HI) mouse model, a new replication-competent clone belonging to HBV genotype B named pAAV-HBV-B containing 1.3 fold genome of HBV genotype B was constructed
It is worth pointing out that the peak mIFN-a concentration and the decline was identical if pAAV-HBV-A and pAAV-HBV-B infection clones were co-applied

Summary

Introduction

Hepatitis B virus (HBV) is a DNA virus causing chronic infections of the human liver [1]. Inhibition of HBV infection can be achieved by suppressing viral replication. IFN-alpha (IFN-a) and nucleoside/ nucleotide analogs [4,5,6] are mainly used for therapies of chronic hepatitis B (CHB). In contrast to nucleoside analogs, IFN-a is able to enhance host immune responses and promote cellular immune responses, mediating inhibition of HBV replication and gene expression [7,8]. Several previous studies have suggested that IFN-a therapy may have long-term beneficial effects in terms of viral clearance, prevention of HCC and prolonging survival in patients with CHB [10,11]. Compared to nucleoside/nucleotide analogs, the advantage of IFN-a therapy includes a more durable response, with the benefit of lacking emergence of drug resistant HBV mutants during the course of treatment. HBsAg loss associated with standard IFN-a therapy has been reported in European studies, with the loss of HBsAg within 1 year of treatment in 5-10% of recipients [12]

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