Short- and long-term outcome of interferon therapy for chronic hepatitis B infection

Hepatitis B virus (HBV) infection is a serious clinical problem worldwide. Conventional interferon (IFN)-α has been approved for the treatment of chronic hepatitis B (CHB). Short-term studies have demonstrated that IFN-based therapy is moderately effective in inducing the loss of hepatitis e antigen (HBeAg) or seroconversion (30%-40%) in HBeAg-positive patients and also produces sustained HBV DNA suppression (20%-30%) in HBeAg-negative patients. Many studies have reported a correlation between the HBV genotype and response to IFN treatment. The highest response rate to IFN treatment was found in patients infected with HBV genotype A, followed by HBV genotypes B, C, and D. The long-term effect of IFN-α on CHB has not yet been elucidated. The ability of IFN-α treatment to prevent new cirrhosis, complications associated with cirrhosis, and development of hepatocellular carcinoma (HCC) is controversial. The beneficial effect of IFN-α treatment in reducing the development of HCC has mainly been observed in treatment responders who already have cirrhosis. These inconsistent findings may be attributed to the inevitable limitations of comparisons across studies, including differences in the baseline characteristics of the study and the moderate suppression of HBV replication by IFN-α relative to nucleoside/nucleos(t)ide analogs.     

HCV dsRNA-Activated Macrophages Inhibit HCV Replication in Hepatocytes

Background:

Macrophages play critical roles in innate immune response in the liver. Whether macrophages participate in liver innate immunity against HCV replication is poorly understood

Objectives:

The aim of this study was to investigate the role of macrophages in liver innate immunity against HCV replication.

Materials and Methods:

Freshly isolated monocytes were purified from peripheral blood of healthy adult donors. Macrophages refer to 7-day-cultured monocytes in vitro. A hepatoma cell line (Huh7) was infected with HCV JFH-1 to generate in vitro HCV infectious system. RT-PCR was used to determine HCV RNA and mRNA levels of genes expression. ELISA was used to measure the protein level of interferon-α (IFN-α) and western blot was used to determine protein expression level of Toll-like receptor 3 (TLR3).

Results:

HCV dsRNA induced the expression of type I IFN (IFN-α/β) in monocyte-derived macrophages. HCV dsRNA also induced the expression of TLR3 and IFN regulatory factor-7 (IRF-7), the key regulators of the IFN signaling pathway. When HCV JFH-1-infected Huh7 cells were co-cultured with macrophages activated with HCV dsRNA or incubated in media conditioned with supernatant (SN) from HCV dsRNA-activated macrophages, HCV replication was significantly suppressed. This macrophage SN action on HCV inhibition was mediated through type I IFN, which was evidenced by the observation that antibody to type I IFN receptor could neutralize the macrophages-mediated anti-HCV effect. The role of type I IFN in macrophages-mediated anti-HCV activity is further supported by the observation that HCV dsRNA-activated macrophages SN treatment induced the expression of several IFN-stimulated genes (ISGs), ISG15, ISG56, OAS-1, OAS-2, MxA and Viperin in HCV-infected Huh7 cells.

Conclusions:

Macrophages may play an important role in liver innate immunity against HCV replication through a type I IFN-dependent mechanism.     

TNF-Mediated Inhibition of Classical Swine Fever Virus Replication Is IRF1-, NF-κB- and JAK/STAT Signaling-Dependent

The sera from pigs infected with virulent classical swine fever virus (CSFV) contain substantial amounts of tumor necrosis factor (TNF), a prototype proinflammatory cytokine with pleiotropic activities. TNF limits the replication of CSFV in cell culture. In order to investigate the signaling involved in the antiviral activity of TNF, we employed small-molecule inhibitors to interfere specifically with JAK/STAT and NF-κB signaling pathways in near-to-primary endothelial PEDSV.15 cells. In addition, we knocked out selected factors of the interferon (IFN) induction and signaling pathways using CRISPR/Cas9. We found that the anti-CSFV effect of TNF was sensitive to JAK/STAT inhibitors, suggesting that TNF induces IFN signaling. Accordingly, we observed that the antiviral effect of TNF was dependent on intact type I IFN signaling as PEDSV.15 cells with the disrupted type I IFN receptor lost their capacity to limit the replication of CSFV after TNF treatment. Consequently, we examined whether TNF activates the type I IFN induction pathway. With genetically modified PEDSV.15 cells deficient in functional interferon regulatory factor 1 or 3 (IRF1 or IRF3), we observed that the anti-CSFV activity exhibited by TNF was dependent on IRF1, whereas IRF3 was dispensable. This was distinct from the lipopolysaccharide (LPS)-driven antiviral effect that relied on both IRF1 and IRF3. In agreement with the requirement of IRF1 to induce TNF- and LPS-mediated antiviral effects, intact IRF1 was also essential for TNF- and LPS-mediated induction of IFN-β mRNA, while the activation of NF-κB was not dependent on IRF1. Nevertheless, NF-κB activation was essential for the TNF-mediated antiviral effect. Finally, we observed that CSFV failed to counteract the TNF-mediated induction of the IFN-β mRNA in PEDSV.15 cells, suggesting that CSFV does not interfere with IRF1-dependent signaling. In summary, we report that the proinflammatory cytokine TNF limits the replication of CSFV in PEDSV.15 cells by specific induction of an IRF1-dependent antiviral type I IFN response.     

Murine Coronavirus Cell Type Dependent Interaction with the Type I Interferon Response

Coronaviruses infect many species of animal including humans, causing acute and chronic diseases of many organ systems. Murine coronavirus, mouse hepatitis virus (MHV) infection of the mouse, provides animal models for the study of central nervous system disease, including encephalitis and demyelinating diseases such as Multiple Sclerosis and for hepatitis. While there are many studies of the adaptive immune response to MHV, there has until recently been scant information on the type I interferon (IFN) response to MHV. The relationship between MHV and the IFN-α/β response is paradoxical. While the type I IFN response is a crucial aspect of host defense against MHV in its natural host, there is little if any induction of IFN following infection of mouse fibroblast cell lines in vitro. Furthermore, MHV is relatively resistant to the antiviral effects of IFN-α/β in mouse fibroblast cell lines and in human 293T cells. MHV can, under some circumstances, compromise the antiviral effects of IFN signaling. The nucleocapsid protein as well as the nsp1 and nsp3 proteins of MHV has been reported to have IFN antagonist activity. However, in primary cell types such as plasmacytoid dendritic cells (pDC) and macrophages, IFN is induced by MHV infection and an antiviral state is established. Other primary cell types such as neurons, astrocytes and hepatocytes fail to produce IFN following infection and, in vivo, likely depend on IFN produced by pDCs and macrophages for protection from MHV. Thus MHV induction of IFN-α/β and the ability to induce an antiviral state in response to interferon is extremely cell type dependent. IFN induced protection from MHV pathogenesis likely requires the orchestrated activities of several cell types, however, the cell types involved in limiting MHV replication may be different in the liver and in the immune privileged CNS.     

LRRFIP1 Inhibits Hepatitis C Virus Replication by Inducing Type I Interferon in Hepatocytes

Background:

Hepatitis C virus infection is one of the leading causes of end stage liver diseases. The innate immune response slows down viral replication by activating cytokines such as type I interferon (IFN-α/β), which trigger the synthesis of antiviral proteins and modulate the adaptive immune system. Recently, leucine-rich repeat (in Flightless I) interacting protein-1 (LRRFIP1) was reported contributing to the production of interferon-β in macrophages.

Objectives:

The aim of this study was to assess the role of LRRFIP1 in induction of IFN-β and inhibition of HCV infection in hepatocytes.

Materials and Methods:

Induction of IFN-β by LRRFIP1 in Huh7 and Huh7.5.1 was determined by real-time PCR and western blotting in vitro. Inhibition of HCV replication by LRRFIP1 overexpression in hepatocytes was assessed.

Results:

LRRFIP1 increased the expression of IFN-β in hepatocytes with or without HCV infection. Induction of IFN-β by LRRFIP1 was enhanced with the presence of hepatitis C virus. Overexpression of LRRFIP1 in hepatocytes inhibited HCV replication. However, HCV infection did not regulate intracellular expression of LRRFIP1.

Conclusions:

LRRFIP1 and its mediated production of type I interferon play a role in controlling HCV infection. The findings of this study provide new target for HCV treatment and contribute to development of anti-HCV drugs.     

IFN-λ1 Displays Various Levels of Antiviral Activity In Vitro in a Select Panel of RNA Viruses

Type III interferons (lambda IFNs) are a quite new, small family of three closely related cytokines with interferon-like activity. Attention to IFN-λ is mainly focused on direct antiviral activity in which, as with IFN-α, viral genome replication is inhibited without the participation of immune system cells. The heterodimeric receptor for lambda interferons is exposed mainly on epithelial cells, which limits its possible action on other cells, thus reducing the likelihood of developing undesirable side effects compared to type I IFN. In this study, we examined the antiviral potential of exogenous human IFN-λ1 in cellular models of viral infection. To study the protective effects of IFN-λ1, three administration schemes were used: ‘preventive’ (pretreatment); ‘preventive/therapeutic’ (pre/post); and ‘therapeutic’ (post). Three IFN-λ1 concentrations (from 10 to 500 ng/mL) were used. We have shown that human IFN-λ1 restricts SARS-CoV-2 replication in Vero cells with all three treatment schemes. In addition, we have shown a decrease in the viral loads of CHIKV and IVA with the ‘preventive’ and ‘preventive/therapeutic’ regimes. No significant antiviral effect of IFN-λ1 against AdV was detected. Our study highlights the potential for using IFN-λ as a broad-spectrum therapeutic agent against respiratory RNA viruses.     

DNA-dependent activator of interferon-regulatory factors inhibits hepatitis B virus replication

AIM: To investigate whether DNA-dependent activator of interferon-regulatory factors (DAI) inhibits hepatitis B virus (HBV) replication and what the mechanism is.METHODS: After the human hepatoma cell line Huh7 was cotransfected with DAI and HBV expressing plasmid, viral protein (HBV surface antigen and HBV e antigen) secretion was detected by enzyme-linked immunosorbent assay, and HBV RNA was analyzed by real-time polymerase chain reaction and Northern blotting, and viral DNA replicative intermediates were examined by Southern blotting. Interferon regulatory factor 3 (IRF3) phosphorylation and nuclear translocation were analyzed via Western blotting and immunofluorescence staining respectively. Nuclear factor-κB (NF-κB) activity induced by DAI was detected by immunofluorescence staining of P65 and dual luciferase reporter assay. Transwell co-culture experiment was performed in order to investigate whether the antiviral effects of DAI were dependent on the secreted cytokines.RESULTS: Viral protein secretion was significantly reduced by 57% (P < 0.05), and the level of total HBV RNA was reduced by 67% (P < 0.05). The viral core particle-associated DNA was also dramatically down-regulated in DAI-expressing Huh7 cells. Analysis of involved signaling pathways revealed that activation of NF-κB signaling was essential for DAI to elicit antiviral response in Huh7 cells. When the NF-κB signaling pathway was blocked by a NF-κB signaling suppressor (IκBα-SR), the anti-HBV activity of DAI was remarkably abrogated. The inhibitory effect of DAI was independent of IRF3 signaling and secreted cytokines.CONCLUSION: This study demonstrates that DAI can inhibit HBV replication and the inhibitory effect is associated with activation of NF-κB but independent of IRF3 and secreted cytokines.     

Pegylated Interferon α Therapy in Chronic Delta Hepatitis: A One-Center Experience

Background:

The only established therapy for chronic viral delta hepatitis, the most severe form of viral hepatitis is treatment with pegylated-interferon α (Peg IFN α).

Objectives:

In this study, we aimed to determine the efficacy of pegylated-interferon α 2a (Peg-IFN α 2a) and 2b (Peg IFN α 2b) in the treatment of patients infected with chronic delta hepatitis virus.

Patients and Methods:

The sample size was based on available patients potentially to be recruited. Data of 63 patients receiving either Peg IFN alpha 2a or Peg IFN alpha 2b were retrospectively assessed in the present cohort study performed in Turkey. Of 56 patients completed the study, 41 received Peg IFN α 2a and 15 received Peg IFN α 2b for 12 months. Patients were evaluated for biochemical and virological responses at the end of given treatment and six months after the treatment.

Results:

Stage of fibrosis was found high in both groups (85.4% vs. 86.7%), while cirrhosis was higher in the group of Peg IFN α 2b (53.3% vs. 34.1%). At the end of treatment, either hepatitis delta virus RNA (HDV RNA) alone or both HDV RNA and hepatitis b virus DNA (HBV DNA) had negative results in 32% of patients. Although HDV RNA negativity was sustained in 30.3% of patients, negativity of both HDV RNA and HBV DNA was decreased to 19.6% six months after completion of the treatment. HBV DNA became positive in one third of patients with response at six months after completion of the treatment (10.7% of all patients). HDV RNA negativity at month six was found as a predictor of positive response. No significant difference was found between Peg IFN α 2a and Peg IFN α 2b for virological response rate.

Conclusions:

Treatment with Peg IFN α achieved a sustained negativity of HDV RNA in about one third of patients. Duration of Peg IFN α therapy might be prolonged to at least 24 months or more to prevent the occurrence of Hepatitis B virus (HBV) relapse encountered six months after completion of the treatment.     

Saturated Fatty Acid Inhibits Viral Replication in Chronic Hepatitis B Virus Infection With Nonalcoholic Fatty Liver Disease by Toll-Like Receptor 4-Mediated Innate Immune Response

Background:

Chronic Hepatitis B (CHB) infection is common in patients with Non-Alcoholic Fatty Liver Disease (NAFLD). The replication level of Hepatitis B Virus (HBV) was inversely correlated with hepatic steatosis. Toll-Like Receptor (TLR) 4-mediated innate immunity plays a pivotal role in the occurrence of NAFLD and controls HBV replication.

Objectives:

This study aimed to investigate whether the TLR4-mediated innate immunity stimulates the pathogenesis of CHB in patients with NAFLD and to determine whether TLR4 plays a role in inhibiting HBV replication.

Materials and Methods:

The HBV transgenic mice were randomized into the HBV and HBV/NAFLD groups. HepG2.2.15 cells were treated with different concentrations (0 – 200 μM) of Stearic Acid (SA) to induce steatosis. The total RNA of the liver tissue was extracted for Real-Time Polymerase Chain Reaction (RT-PCR) detection, and immunohistochemistry or western blot was conducted for further validation. The Enzyme-Linked Immunosorbent Assay (ELISA) analysis was applied to evaluate the production of Interleukin 6 (IL-6), Tumor necrosis factor α (TNF-α) and Interferon β (IFN-β). Moreover, viral dynamics were analyzed using HBV DNA and HBV-related antigens (HBsAg and HBeAg).

Results:

Non-alcoholic fatty liver disease was induced in HBV-transgenic mice fed with High Fat Diet (HFD) for 8 - 24 weeks. Oil red-O staining positive droplets and the content of Triglyceride (TG) were increased in HepG2.2.15 cells treated with SA. TLR4, Myeloid differentiation factor 88 (MyD88), IL-6 and TNF-α expression levels were significantly higher in the HBV/NAFLD group and the steatotic HepG2.2.15 cells than those in their respective controls. Compared to the HBV group, significant reductions in serum levels of HBsAg, HBeAg, and HBV DNA titers occurred in the HBV/NAFLD group at 24 weeks, but the IFN-β level was remarkably increased. Similar data were also obtained from the steatoric HepG2.2.15 cells.

Conclusions:

Saturated Fatty Acids (SFAs) served as a potential ligand for TLR4 and activated TLR4 signaling pathway, which might be involved in the pathogenesis. Thus, SFAs can accelerate the mechanism of inhibiting HBV replication in CHB with NAFLD.     

Divergent susceptibilities of human herpesvirus 6 variants to type I interferons

Two distinct human herpesvirus 6 (HHV-6) variants infect humans. HHV-6B is the etiologic agent of roseola and is associated with life-threatening neurological diseases, such as encephalitis, as well as organ transplant failure. The epidemiology and disease association for HHV-6A remain ill-defined. Specific anti-HHV-6 drugs do not exist and classic antiherpes drugs have secondary effects that are often problematic for transplant patients. Clinical trials using IFN were also performed with inconclusive results. We investigated the efficacy of type I IFN (α/β) in controlling HHV-6 infection. We report that cells infected with laboratory strains and primary isolates of HHV-6B are resistant to IFN-α/β antiviral actions as a result of improper IFN-stimulated gene (ISGs) expression. In contrast, HHV-6A-infected cells were responsive to IFN-α/β with pronounced antiviral effects observed. Type II IFN (γ)-signaling was unaltered in cells infected by either variant. The HHV-6B immediate-early 1 (IE1) physically interacts with STAT2 and sequestrates it to the nucleus. As a consequence, IE1B prevents the binding of ISGF3 to IFN-responsive gene promoters, resulting in ISG silencing. In comparison, HHV-6A and its associated IE1 protein displayed marginal ISG inhibitory activity relative to HHV-6B. The ISG inhibitory domain of IE1B mapped to a 41 amino acid region absent from IE1A. Transfer of this IE1B region resulted in a gain of function that conferred ISG inhibitory activity to IE1A. Our work is unique in demonstrating type I IFN signaling defects in HHV-6B-infected cells and highlights a major biological difference between HHV-6 variants.     

Effects of antiviral therapy on preventing liver tumorigenesis and hepatocellular carcinoma recurrence

Chronic hepatitis B virus(HBV)infection is the key driving force of liver disease progression,resulting in the development of hepatic dysfunction,cirrhosis and hepatocellular carcinoma(HCC).The primary aim of therapy is to suppress or eliminate HBV replication to reduce the activity of hepatitis,thus reducing the risk of,or slowing the progression of,liver disease.Nucleos(t)ide analogues(Nucs)may result in rapid suppression of HBV replication with normalization of serum transaminases and restore liver function,thus increasing survival in patients with hepatic decompensation.Long-term Nuc therapy may result in histological improvement or reversal of advanced fibrosis and reduction in disease progression,including the development of HCC.The long-term benefits of a finite course of interferon(IFN)-αtherapy also include a sustained and cumulative response,as well as hepatitis B surface antigen seroclearance and reduction in the development of cirrhosis and/or HCC.Pegylated IFN and newer Nucs may achieve better long-term outcomes because of improved efficacy and a low risk of drug resistance.However,treatment outcomes are still far from satisfactory.Understanding the effects of anti-HBV treatment against HCC incidence and recurrence after hepatectomy or liver transplantation is required for further improvement of outcome.     

Prothymosin-α inhibits HIV-1 via Toll-like receptor 4-mediated type I interferon induction

Induction of type I interferons (IFN) is a central feature of innate immune responses to microbial pathogens and is mediated via Toll-like receptor (TLR)-dependent and -independent pathways. Prothymosin-α (ProTα), a small acidic protein produced and released by CD8⁺ T cells, inhibits HIV-1, although the mechanism for its antiviral activity was not known. We demonstrate that exogenous ProTα acts as a ligand for TLR4 and stimulates type I IFN production to potently suppress HIV-1 after entry into cells. These activities are induced by native and recombinant ProTα, retained by an acidic peptide derived from ProTα, and lost in the absence of TLR4. Furthermore, we demonstrate that ProTα accounts for some of the soluble postintegration HIV-1 inhibitory activity long ascribed to CD8⁺ cells. Thus, a protein produced by CD8⁺ T cells of the adaptive immune system can exert potent viral suppressive activity through an innate immune response. Understanding the mechanism of IFN induction by ProTα may provide therapeutic leads for IFN-sensitive viruses.     

Interferon β transduction of peripheral blood lymphocytes from HIV-infected donors increases Th1-type cytokine production and improves the proliferative response to recall antigens

We are developing a gene therapy method of HIV infection based on the constitutive low production of interferon (IFN) β. Peripheral blood lymphocytes (PBL) from HIV-infected patients at different clinical stages of infection were efficiently transduced with the HMB-H^bHuIFNβ retroviral vector. The constitutive low production of IFN-β in cultured PBL from HIV-infected patients resulted in a decreased viral production and an enhanced survival of CD4⁺ cells, and this protective effect was observed only in the PBL derived from donors having a CD4⁺ cell count above 200 per mm³. In IFN-β-transduced PBL from healthy and from HIV-infected donors, the production of the Th1-type cytokines IFN-γ and interleukin (IL)-12 was enhanced. In IFN-β-transduced PBL from HIV-infected donors, the production of IL-4, IL-6, IL-10, and tumor necrosis factor α was maintained at normal levels, contrary to the increased levels produced by the untransduced PBL. The proliferative response to recall antigens was partially restored in IFN-β-transduced PBL from donors with an impaired antigen response. Thus, in addition to inhibiting HIV replication, IFN-β transduction of PBL from HIV-infected donors improves several parameters of immune function.     

The Innate Immune Playbook for Restricting West Nile Virus Infection

West Nile virus (WNV) is an emerging mosquito-borne flavivirus that causes annual epidemics of encephalitic disease throughout the world. Despite the ongoing risk to public health, no approved vaccines or therapies exist for use in humans to prevent or combat WNV infection. The innate immune response is critical for controlling WNV replication, limiting virus-induced pathology, and programming protective humoral and cell-mediated immunity to WNV infection. The RIG-I like receptors, Toll-like receptors, and Nod-like receptors detect and respond to WNV by inducing a potent antiviral defense program, characterized by production of type I IFN, IL-1β and expression of antiviral effector genes. Recent research efforts have focused on uncovering the mechanisms of innate immune sensing, antiviral effector genes that inhibit WNV, and countermeasures employed by WNV to antagonize innate immune cellular defenses. In this review, we highlight the major research findings pertaining to innate immune regulation of WNV infection.     

Effect of spleen operation on antiviral treatment in hepatitis C virus-related cirrhotic patients

AIM: To investigate the impact of spleen operation (SO) on interferon-α (IFN-α)-based antiviral treatment in patients with hepatitis C virus (HCV)-related cirrhosis.METHODS: Studies were systematically identified by searching electronic databases including MEDLINE, Cochrane Library, Elsevier, and Embase up to September 30, 2013, and relevant clinical studies were reviewed. Sustained virological response (SVR) rate and adherence to therapy were taken as the endpoints of interest.RESULTS: A total of 603 patients from 16 studies were included in the systematic review. Of 372 patients who underwent SO followed by antiviral treatment, the total SVR rate was 39.5%. SVR was associated with HCV genotypes 2/3 (OR = 10.84; 95%CI: 5.47-21.47; P < 0.00001). IFN-α dose needed to be reduced in 29.4%, and IFN-α-based therapy was discontinued in 11.5% of patients. Analysis of controlled studies showed that SVRs were achieved in 34.1% of patients with SO and 31.1% of patients without SO. SO had no effect on the SVR rate in cirrhotic patients with genotype 1 HCV infection (OR = 1.28; 95%CI: 0.51-3.22; P = 0.60), but improved the SVR rate in patients with genotypes 2/3 infection, though the difference was not significant (OR = 0.36; 95%CI: 0.13-1.02; P = 0.05).CONCLUSION: SO combined with IFN-α-based antiviral therapy may be suitable in cirrhotic patients with genotypes 2/3 HCV infection, but not in those with genotype 1 infection.