The Role of Immune Cells in Chronic HBV Infection

The interactive role of microRNA and other non-coding RNA in hepatitis B (HBV) associated fibrogenesis

One of the outstanding features of chronic hepatitis B infection (CHB) is its strong association with liver fibrosis. CHB induced inflammation and injury trigger multiple biochemical and physical changes that include the promotion of a wide range of cytokines, chemokines and growth factors that activate hepatic stellate cells (HSCs) CHB induced activation of hepatic stellate cells (HSCs) is regarded as a central event in fibrogenesis to directly promote the synthesis of myofibroblasts and the expression of a range of materials to repair injured liver tissue. Fibrogenesis is modulated by the mainstream epigenetic machinery, as well as by non-coding RNA (ncRNA) that are often referred to as an ancillary epigenetic response to fine tune gene expression. Although extensive research has explained the regulatory role of ncRNA in liver fibrogenesis, most of this research relates to non-CHB etiologies. This review paper outlines the complex interactive regulatory role of microRNA (miRNA) and their interaction with long non-coding RNA (lncRNA), circular RNA (circRNA) and the mainstream epigenetic machinery in CHB induced liver fibrosis. The paper also illustrates some of the difficulties involved in translating candidate ncRNA into approved drugs or diagnostic tools. In conclusion, the important regulatory role of ncRNA in CHB induced liver fibrosis warrants further investigation to exploit their undoubted potential as diagnostic and therapeutic agents.

Metabolic Reprograming of Macrophages: A New Direction in Traditional Chinese Medicine for Treating Liver Failure

Acute liver failure (ALF) is a fulminant clinical syndrome that usually leads to multiple organ failure and high mortality. Macrophages play a crucial role in the initiation, development, and recovery of ALF. Targeting macrophages through immunotherapy holds significant promise as a therapeutic strategy. These cells exhibit remarkable plasticity, enabling them to differentiate into various subtypes based on changes in their surrounding microenvironment. M1-type macrophages are associated with a pro-inflammatory phenotype and primarily rely predominantly on glycolysis. In contrast, M2-type macrophages, which are characterized by anti-inflammatory phenotype, predominantly obtain their energy from oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO). Shifting macrophage metabolism from glycolysis to OXPHOS inhibits M1 macrophage activation and promotes M2 macrophage activation, thereby exerting anti-inflammatory and reparative effects. This study elucidates the relationship between macrophage activation and glucose metabolism reprograming from an immunometabolism perspective. A comprehensive literature review revealed that several signaling pathways may regulate macrophage polarization through energy metabolism, including phosphatidyl-inositol 3-kinase/protein kinase B (PI3K/AKT), mammalian target of rapamycin (mTOR)/hypoxia-inducible factor 1α (HIF-1α), nuclear factor-κB (NF-κB), and AMP-activated protein kinase (AMPK), which exhibit crosstalk with one another. Additionally, we systematically reviewed several traditional Chinese medicine (TCM) monomers that can modulate glucose metabolism reprograming and influence the polarization states of M1 and M2 macrophages. This review aimed to provide valuable insights that could contribute to the development of new therapies or drugs for ALF.

Genomic instabilities in hepatocellular carcinoma: biomarkers and application in immunotherapies

Hepatocellular carcinoma (HCC) is one of the deadliest cancers. For patients with advanced HCC, liver function decompensation often occurs, which leads to poor tolerance to chemotherapies and other aggressive treatments. Therefore, it remains critical to develop effective therapeutic strategies for HCC. Etiological factors for HCC are complex and multifaceted, including hepatitis virus infection, alcohol, drug abuse, chronic metabolic abnormalities, and others. Thus, HCC has been categorized as a "genomically unstable" cancer due to the typical manifestation of chromosome breakage and aneuploidy, and oxidative DNA damage. In recent years, immunotherapy has provided a new option for cancer treatments, and the degree of genomic instability positively correlates with immunotherapy efficacies. This article reviews the endogenous and exogenous causes that affect the genomic stability of liver cells; it also updates the current biomarkers and their detection methods for genomic instabilities and relevant applications in cancer immunotherapies. Including genomic instability biomarkers in consideration of cancer treatment options shall increase the patients' well-being.

The seroepidemiology of isolated core antibody against hepatitis B among Taiwanese adults - A large hospital-based study

BACKGROUND/PURPOSE

This study aims to investigate the prevalence of isolated core antibodies against hepatitis B (IAHBc) in different birth cohorts using a large medical record database.

METHODS

Hepatitis B viral serological test data were collected from a chart cloud database at a medical center in Taiwan between January 2006 and December 2018. The data collected included birth year, sex, hepatitis B viral markers (HBsAg, anti-HBs or anti-HBc), and hepatitis B vaccination records. Enrolled patients were grouped according to their birth year into three categories: ≤ 1986, 1987-1992, and ≥ 1993, which correspond to no neonatal hepatitis B immunization, plasma-derived HB vaccine (PDHBV), and recombinant hepatitis B vaccine (RHBV), respectively. Prevalence of hepatitis B viral seromarkers, including IAHBc, was calculated by sex, age groups, and birth cohorts. Those who underwent repeated hepatitis B serology tests were included for further analysis to follow up their serostatus.

RESULTS

A total of 117,335 adults with complete hepatitis B serologic data were analyzed. Among them, 6641 individuals (5.7 %) were found to have IAHBc. The prevalence of IAHBc was 11.4 %, 0.8 %, and 0.3 % among those born before 1986, between 1987 and 1992, and after 1992, respectively. Among the 690 subjects with repeated blood tests and complete hepatitis B serologic data, 551 cases (79.9 %) remained IAHBc. The other cases included resolved infection status (13.9 %), seronegativity for three HB seromarkers (3 %), and carrier of hepatitis B virus (2.3 %).

CONCLUSION

The management of individuals with IAHBc should be tailored to their age, vaccination status, and risk factors for occult hepatitis B viral infection.

Mafosfamide Boosts GMI-HBVac against HBV via Treg Depletion in HBV-Infected Mice

Chronic hepatitis B infection remains a significant worldwide health burden, placing persons at risk for hepatocellular cancer and hepatic fibrosis. Chronic hepatitis B virus (CHB) infection is characterized by elevated levels of immunosuppressive regulatory T cells (Tregs), which can inhibit the function of effector T cells and lead to an insufficient immune clearance response against HBV. Theoretically, suppression of Treg cell functionality and percentage could increase anti-HBV reactivity in CHB-infected patients, although this has not yet been explored. We attempted to enhance our previously established anti-CHB protocol utilizing the GM-CSF+IFN-α+rHBVvac regimen (GMI-HBVac) by incorporating mafosfamide (MAF), which has been utilized in anticancer therapy in the past. Intravenous administration of MAF to rAAV8-1.3HBV-infected mice resulted in a dose-dependent reduction of Tregs in the blood, rebounding to pretreatment levels 10 days later. To assess the potential benefit of adding MAF to the anti-CHB protocol, 2 μg/mL MAF was combined with the GMI-HBVac as an anti-Treg treatment in an HBV-infected animal model. When rAAV8-1.3HBV-infected mice were immunized with MAF+GMI-HBVac, peripheral blood Tregs decreased significantly, leading to dendritic cell activation, HBV-specific T cell proliferation, and the upregulation of IFN-gamma-producing CD8⁺T cells. In addition, MAF+GMI-HBVac vaccination stimulated T cell infiltration in HBV-infected livers. These effects may contribute to an enhanced immune response and the clearance of HBV-associated antigens, including serum HBsAg, serum HBcAg, and HBcAg⁺ hepatocytes. Overall, this is the first indication that MAF can act as an adjuvant with GMI-HBVac to deplete Tregs in mice with an established CHB infection. This unique therapeutic vaccine regimen produced a functional cure, as revealed by the remarkable clearance of HBsAg.

LAG3+ erythroid progenitor cells inhibit HBsAg seroclearance during finite pegylated interferon treatment through LAG3 and TGF-β

HBsAg seroclearance, the ideal aim of anti-hepatitis B virus (HBV) treatment, cannot be achieved easily. Anemia is another common issue for chronic hepatitis B (CHB) patients, which leads to elevation of erythroid progenitor cells (EPCs) and immune suppression in cancer. This study investigated the role of EPCs in HBsAg seroclearance following pegylated interferon-α (PEG-IFN) treatment. CD45+EPC accumulation in CHB patients and an AAV/HBV mice model was found in the circulation and liver by flow cytometry and immunofluorescence tests. Wright-Giemsa staining showed that these pathological CD45+EPCs presented elevated erythroid cells with relative immature morphologies and atypical cells compared with the control cells. CD45+EPCs were associated with immune tolerance and decreased HBsAg seroclearance during finite PEG-IFN treatment. CD45+EPCs suppressed antigen non-specific T cell activation and HBV-specific CD8+T cells, partially through transforming growth factor β (TGF-β). RNA-seq revealed that CD45+EPCs in patients with CHB presented a distinct gene expression profile compared with CD45-EPCs and CD45+EPCs from cord blood. Notably, CD45+EPCs from patients with CHB expressed high level of Lymphocyte-activation gene 3 (LAG3), an immune checkpoint molecule, and were then defined as LAG3+EPCs. LAG3+EPCs diminished the function of antigen presenting cells through LAG3, which was another mechanism by which LAG3+EPCs' suppressed HBV-specific CD8+T cells. Anti-LAG3 and anti-TGF-β combination treatment decreased serum HBeAg, HBV DNA levels and HBsAg level, as well as HBsAg-expression in hepatocytes during PEG-IFN treatment in the AAV/HBV mice model. Conclusions: LAG3+EPCs inhibited the efficacy of PEG-IFN treatment on HBsAg seroclearance induced by LAG3 and TGF-β. Anti-LAG3, anti-TGF-β and PEG-IFN combination treatment might facilitate HBV clearance.

Insights into the impact of hepatitis B virus on hepatic stellate cell activation

During chronic hepatitis B virus (HBV) infection, hepatic fibrosis is a serious pathological condition caused by virus-induced liver damage. The activation of hepatic stellate cells (HSCs) is a central event in the occurrence and progression of liver fibrosis. Although accumulating evidence has shown that HBV directly stimulates HSC activation, whether the virus infects and replicates in HSCs remains controversial. Inflammation is one of the obvious characteristics of chronic HBV infection, and it has been demonstrated that persistent inflammation has a predominant role in triggering and maintaining liver fibrosis. In particular, the regulation of HSC activation by HBV-related hepatocytes via various inflammatory modulators, including TGF-β and CTGF, in a paracrine manner has been reported. In addition to these inflammation-related molecules, several inflammatory cells are essential for the progression of HBV-associated liver fibrosis. Monocytes, macrophages, Th17 cells, NK cells, as well as NKT cells, participate in the modulation of HBV-related liver fibrosis by interacting with HSCs. This review summarizes current findings on the effects of HBV and the relevant molecular mechanisms involved in HSC activation. Because HSC activation is essential for liver fibrosis, targeting HSCs is an attractive therapeutic strategy to prevent and reverse hepatic fibrosis induced by HBV infection. Video abstract.

Optimized Cationic Lipid-assisted Nanoparticle for Delivering CpG Oligodeoxynucleotides to Treat Hepatitis B Virus Infection

PURPOSE

Hepatitis B virus (HBV) infection is such a global health problem that hundreds of millions of people are HBV carriers. Current anti-viral agents can inhibit HBV replication, but can hardly eradicate HBV. Cytosine-phosphate-guanosine (CpG) oligodeoxynucleotides (ODNs) are an adjuvant that can activate plasmacytoid dendritic cells (pDCs) and conventional dendritic cells (cDCs) to induce therapeutic immunity for HBV eradication. However, efficient delivery of CpG ODNs into pDCs and cDCs remains a challenge. In this study, we constructed a series of cationic lipid-assisted nanoparticles (CLANs) using different cationic lipids to screen an optimal nanoparticle for delivering CpG ODNs into pDCs and cDCs.

METHODS

We constructed different CLAN_CpG using six cationic lipids and analyzed the cellular uptake of different CLAN_CpG by pDCs and cDCs in vitro and in vivo, and further analyzed the efficiency of different CLAN_CpG for activating pDCs and cDCs in both wild type mice and HBV-carrier mice.

RESULTS

We found that CLAN fabricated with 1,2-Dioleoyl-3-trimethylammonium propane (DOTAP) showed the highest efficiency for delivering CpG ODNs into pDCs and cDCs, resulting in strong therapeutic immunity in HBV-carrier mice. By using CLAN_CpG as an immune adjuvant in combination with the injection of recombinant hepatitis B surface antigen (rHBsAg), HBV was successfully eradicated and the chronic liver inflammation in HBV-carrier mice was reduced.

CONCLUSION

We screened an optimized CLAN fabricated with DOTAP for efficient delivery of CpG ODNs to pDCs and cDCs, which can act as a therapeutic vaccine adjuvant for treating HBV infection.

Prospects for NK-based immunotherapy of chronic HBV infection

Effective and long-term treatment is required for controlling chronic Hepatitis B Virus (HBV) infection. Natural killer (NK) cells are antiviral innate lymphocytes and represent an essential arm of current immunotherapy. In chronic HBV (CHB), NK cells display altered changes in phenotypes and functions, but preserve antiviral activity, especially for cytolytic activity. On the other hand, NK cells might also cause liver injury in the disease. NK -based immunotherapy, including adoptive NK cell therapy and NK -based checkpoint inhibition, could potentially exploit the antiviral aspect of NK cells for controlling CHB infection while preventing liver tissue damage. Here, we review recent progress in NK cell biology under the context of CHB infection, and discuss potential NK -based immunotherapy strategies for the disease.

Clinical Predictors of Functional Cure in Children 1-6 Years-old with Chronic Hepatitis B

BACKGROUND AND AIMS

Hepatitis B surface antigen (HBsAg) clearance is significantly more common in children with chronic hepatitis B (CHB) than in adults; however, the possible influencing factors related to HBsAg loss have yet to be found. This study aimed to explore the efficacy of long-term interferon (IFN)α therapy in treating children with CHB and analyzed the factors influencing functional cure after treatment.

METHODS

A total of 236 children aged 1-6 years and diagnosed with CHB via liver biopsy were included in the study, all receiving IFNα treatment (IFNα-2b monotherapy, IFNα-2b followed by lamivudine [LAM] or IFNα-2b combined with LAM) and followed up for 144 weeks. A comprehensive analysis was conducted on clinical data, including biochemical items, serum markers of hepatitis B virus (HBV) and immunological indexes, and logistic regression analysis was used to screen the influencing factors related to HBsAg loss.

RESULTS

The cumulative loss rates of HBsAg were 79.5%, 62.1% and 42.1% at 144 weeks after the start of treatment in the 1-3 years-old group, 3-5 years-old group and 5-7 years-old group, respectively (p<0.05). IFNα-2b combined with LAM treatment displayed the highest HBsAg loss rates compared with monotherapy and sequential treatment (p=0.011). Younger baseline age and lower HBsAg levels were independent factors for the prediction of HBsAg loss (p<0.05). The baseline PreS1 and hepatitis B core antibody levels in the HBsAg loss group were lower than those in the HBsAg non-loss group. In addition, the PreS1 level was positively corelated with the level of HBsAg, HBV DNA and liver inflammation.

CONCLUSIONS

Long-term treatment with IFNα was effective in achieving HBsAg loss in CHB children aged 1-6 years-old. Age less than 3 years-old and lower HBsAg levels are independent predictors of functional cure in children with CHB.

Circulating IL-1β, IL-17, and IP-10 as Potential Predictors of Hepatitis B Virus Infection Prognosis

Circulating cytokines and chemokines play critical roles in hepatitis B virus (HBV) infection. Here, we explored the effects of proinflammatory and anti-inflammatory effector molecules on HBV progression, e antigen seroconversion, and liver function. Our results showed that circulating interleukin (IL)-17 may be helpful in HBV spontaneous clearance [odds ratio (OR) = 1.468, 95%confidence interval (CI) = 1.080–1.995, P = 0.014] and protective against HBV-related hepatoma development (OR = 0.933, 95%CI = 0.910–0.957, P < 0.001). IL-1β negatively affected HBV clearance (OR = 0.052, 95%CI = 0.005–0.534, P = 0.013). In patients with chronic hepatitis B, interferon-γ-inducible protein-10 (IP-10) levels significantly increased in the group of abnormal liver function (P = 0.006). Furthermore, positive correlations of IP-10 with alanine aminotransferase and aspartate aminotransferase levels were observed (r_s = 0.546 and 0.644, respectively; P < 0.001). In conclusion, inflammatory cytokines and chemokines may be a “double-edged sword” for HBV clearance and progression. Further exploration of the roles of IL-17, IL-1β, and IP-10 in chronic HBV infection is needed.

Comparative expression of pro-inflammatory and apoptotic biosignatures in chronic HBV-infected patients with and without liver cirrhosis

The interplay of immune mediators is paramount to optimal host anti-viral immune responses, especially against chronic hepatitis B virus (HBV) infection. Here, we investigated the dynamic changes in host immune responses in chronic HBV-infected individuals with and without liver cirrhosis by examining the signatures of apoptosis and plasma levels of pro-inflammatory cytokines, chemokines, and cytotoxic proteins. A total of 40 chronic HBV patients with and without liver cirrhosis were studied for plasma levels of immune mediators, and signatures of apoptosis in peripheral blood mononuclear cells (PBMCs). The intracellular concentrations of reactive oxygen species (ROS) in patients with chronic HBV with liver cirrhosis was relatively higher as compared to chronic HBV patients. The onset of apoptosis was sustained due to ongoing liver inflammation in concert with plasma TNF-α and IL-6 levels. Plasma VEGF was upregulated among chronic HBV patients with liver cirrhosis, whereas CCL2, CCL5 and granzyme B levels were down-regulated. High levels of ROS, IL-6 and TNF-α correlated with ongoing inflammation among chronic HBV patients with liver cirrhosis, which likely attributed to the expression of biosignatures of apoptosis and activation in immune cells.

TLR3 Mediates Senescence and Immunosurveillance of Hepatic Stellate Cells

Background: Activation of hepatic stellate cells (HSCs) is an important driver of liver fibrosis, which is a health problem of global concern, and there is no effective solution for it at the present. Senescent activated HSCs are preferentially killed by natural killer cells (NK cells) to promote the regression of hepatic fibrosis. Objectives: The purpose of this study was to investigate the effect of polyinosinic-polycytidylic acid (poly I:C) on HSCs’ senescence, a trigger for NK cell-induced cytotoxicity. Methods: The senescence of HSCs was assessed by western blot, qRT-PCR, and flow cytometry, and NK cell cytotoxicity was assessed in a co-culture of NK cells with poly I:C-treated HSCs by measuring CD107a expression. Results: The expression of p16, p21, SA-β-gal, MICA/MICB, and ULBP2 increased in poly I:C-treated HSCs, rendering them significantly susceptible to NK cell cytotoxicity. Conclusions: Poly I:C induces cellular senescence in HSCs and triggers NK cell immunosurveillance, suggesting that the role of poly I:C in HSC senescence may promote fibrosis regression.

Immunopathology of Chronic Hepatitis B Infection: Role of Innate and Adaptive Immune Response in Disease Progression

More than 250 million people are living with chronic hepatitis B despite the availability of highly effective vaccines and oral antivirals. Although innate and adaptive immune cells play crucial roles in controlling hepatitis B virus (HBV) infection, they are also accountable for inflammation and subsequently cause liver pathologies. During the initial phase of HBV infection, innate immunity is triggered leading to antiviral cytokines production, followed by activation and intrahepatic recruitment of the adaptive immune system resulting in successful virus elimination. In chronic HBV infection, significant alterations in both innate and adaptive immunity including expansion of regulatory cells, overexpression of co-inhibitory receptors, presence of abundant inflammatory mediators, and modifications in immune cell derived exosome release and function occurs, which overpower antiviral response leading to persistent viral infection and subsequent immune pathologies associated with disease progression towards fibrosis, cirrhosis, and hepatocellular carcinoma. In this review, we discuss the current knowledge of innate and adaptive immune cells transformations that are associated with immunopathogenesis and disease outcome in CHB patients.

HMGB1: An overview of its roles in the pathogenesis of liver disease

High-mobility group box 1 (HMGB1) is an abundant architectural chromosomal protein that has multiple biologic functions: gene transcription, DNA replication, DNA-damage repair, and cell signaling for inflammation. HMGB1 can be released passively by necrotic cells or secreted actively by activated immune cells into the extracellular milieu after injury. Extracellular HMGB1 acts as a damage-associated molecular pattern to initiate the innate inflammatory response to infection and injury by communicating with neighboring cells through binding to specific cell-surface receptors, including Toll-like receptors (TLRs) and the receptor for advanced glycation end products (RAGE). Numerous studies have suggested HMGB1 to act as a key protein mediating the pathogenesis of chronic and acute liver diseases, including nonalcoholic fatty liver disease, hepatocellular carcinoma, and hepatic ischemia/reperfusion injury. Here, we provide a detailed review that focuses on the role of HMGB1 and HMGB1-mediated inflammatory signaling pathways in the pathogenesis of liver diseases.

The unique characteristic in peripheral immune cells in patients with advanced hepatocellular carcinoma

BACKGROUND/PURPOSE

Recent progress in cancer immunology provides more insight in immune evasion of cancer cells. Cancer cells may achieve immune evasion through several ways including ineffective antigen presentation, T cell checkpoint utilization, immunosuppressive cytokines secretion and immunosuppressive cells recruitment. However, few literatures mentioned about the change of peripheral blood immune cells in advanced hepatocellular carcinoma (HCC) patients. To answer this question, we initiated a pilot study through detailed flow cytometry.

METHODS

We enrolled patients with advanced HCC patients who had informed consent to the collection of their peripheral blood. We also recruited healthy individuals for the control group. Using flow cytometry, we analyzed lymphocyte subclasses and the PD-1 or PD-L1 positivity of immune cells in peripheral blood from HCC patients and healthy individuals.

RESULTS

Twenty-four HCC patients were enrolled and twenty healthy individuals were enrolled. Most of the HCC patients were HBV carrier (58.3%), and the mean age was 61 years old. Among 55 immune cell parameters we examined in peripheral blood, 16 were significantly different between advanced HCC patients and healthy individuals by univariate analysis. Multivariate analysis was then conducted by fitting logistic regression model and showed that CD69^-CD25^- Naïve CD4αβT cell percentage and dendritic cell percentage can reasonably predict the advanced HCC status from peripheral blood. By our regression model, the adjusted generalized R2 = 0.918 and the estimated area under the Receiver Operating Characteristic (ROC) curve was 0.99.

CONCLUSION

CD69^-CD25^- Naïve CD4αβT cell percentage and dendritic cell percentage in peripheral blood are highly correlated with the advanced HCC status. The change may result from immune evasion initiated by hepatocellular carcinoma cells and further investigation is warranted. Validation study is ongoing and this mechanism may be utilized to treat advanced HCC patient in the future.

Association among cytokine profiles of innate and adaptive immune responses and clinical-virological features in untreated patients with chronic hepatitis B

Background

Complete clearance of intracellular viruses depends on effector cells of innate and adaptive immune systems. This study aimed to identify the relationships among antiviral cytokines produced by natural killer (NK) and T cells and clinical-virological characteristics in untreated chronic hepatitis B (CHB) patients.

Methods

We measured antiviral cytokines interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and interleukin-2 (IL-2) produced by T, NK and natural killer T (NKT) cells, respectively, in a cohort with chronic hepatitis B virus (HBV) infection (CHB). We also correlated these cytokines with clinical-virological characteristics using a linear regression model.

Results

levels of IFN-γ⁺ and TNF-α⁺ CD4⁺ and CD8⁺ T cells were significantly higher in immune active (IA) phase than in other phases. Immune tolerant (IT) patients showed the lowest expression of IFN-γ by NK and NKT cells, and TNF-α by NK cells. IFN-γ⁺, TNF-α⁺ and IL-2⁺ CD4⁺ and CD8⁺ T cells frequencies were similar between IA and gray zone (GZ) phases. Principal component analysis based on cytokines confirmed that most IT patients significantly differed from inactive carriers (IC) and IA patients, while GZ patients were widely scattered. Multivariate analysis showed both T and NK cells producing IFN-γ and TNF-α, but not IL-2, had significant association with serum alanine aminotransferase (ALT). Moreover, IFN-γ⁺ NKT cells were associated with HBV DNA, while IFN-γ⁺ CD4⁺ and CD8⁺ T cells were correlated with age.

Conclusion

HBV clinical phases are characterized by distinct cytokine signatures, which showed relationship to viral features in these untreated CHB patients.

Hepatitis B e Antigen Induces NKG2A+ Natural Killer Cell Dysfunction via Regulatory T Cell-Derived Interleukin 10 in Chronic Hepatitis B Virus Infection

Although persistent hepatitis B virus (HBV) infection is associated with natural killer (NK) cell dysfunction, it remains obscure whether HBV viral antigens are responsible for NK cell dysfunction in patients with chronic hepatitis B (CHB) infection. In this study, we found that the percentage of NK cells expressing the inhibitory receptor, NKG2A, was increased in CHB patients, and NKG2A blockade restored NK cell function. Furthermore, in CHB patients, the frequency of NK cells expressing NKG2A positively correlated with the number of regulatory T cells (Tregs) and production of interleukin-10 (IL-10) in these Tregs. Moreover, exposure of peripheral blood mononuclear cells (PBMCs) isolated from healthy controls to sera from CHB patients resulted in increased proportion of NKG2A⁺ NK cells; IL-10 blockade reduced the frequency of NKG2A⁺ NK cells while increasing the percentage of IFN-γ⁺ NK cells. In addition, stimulation of NK cells and Tregs from healthy controls with CHB sera together with anti-IL-10 antibody increased IFN-γ production in the culture supernatant. The frequencies of NKG2A⁺ NK cells and IL-10⁺ Tregs, along with serum levels of alanine transferase and HBV DNA, were significantly increased in CHB patients positive for the Hepatitis B e antigen (HBeAg, a marker of viral replication) when compared to HBeAg-negative CHB patients. Importantly, exposure of PBMCs from healthy controls to HBeAg resulted in increased IL-10 production but reduced levels of TNF and IFN-γ, and IL-10 blockade rescued the generation of TNF and IFN-γ in this assay. The reduced production of TNF and IFN-γ was also observed in NK cells and Tregs from healthy controls that were stimulated with HBeAg, while IL-10 blockade increased the secretion of these two cytokines. We conclude that HBeAg induces IL-10 production in Tregs, thereby leading to increased expression of NKG2A on NK cells, which contributes to NK cell dysfunction during CHB infection. These data suggest that HBeAg is associated with NK cell dysfunction in CHB.

Anti-HBV activity of retinoid drugs in vitro versus in vivo

We describe here the anti-HBV activity of natural and synthetic retinoids in primary human hepatocytes (PHHs). The most potent compounds inhibited HBsAg, HBeAg, viral RNA and DNA production by HBV infected cells with EC₅₀ values ranging from 0.4 to 2.6 μM. The activity was independent of PHH donor and HBV genotype used in testing. 13-cis retinoic acid (Accutane) was selected for further evaluation in the PXB chimeric mouse model of HBV infection at doses allowing to achieve Accutane peak serum concentrations near its antiviral EC₉₀ and exposures ∼5-fold higher than a typical clinical dose. While these supraclinical exposures of 100 mg/kg/day were well-tolerated by regular Balb/c mice, PXB mice were more sensitive and even a lower those of 60 mg/kg/day led to significant weight loss. Despite dosing at this maximal tolerated dose for 28 days, Accutane failed to show any anti-HBV activity. RAR target engagement was verified using transcriptome analysis of liver samples from treated versus vehicle groups. However, gene expression changes in PXB liver samples were vastly muted when compared to the in vitro PHH system. When comparing transcriptional changes associated with the conditioning of fresh hepatocytes toward enabling HBV infection, we also observed a large number of changes. Noticeably, a significant number of genes that were up- or down-regulated by the conditioning process were down- or up-regulated by HBV infected PHH treatment with Accutane, respectively. While the lack of efficacy in the PXB model may have many explanations, the observed, opposing transcriptional changes upon conditioning PHH and treating these cultured, HBV-infected PHH with Accutane allow for the possibility that the PHH system may yield artificial anti-HBV hits.

Expression of autophagy-modulating genes in peripheral blood mononuclear cells from familial clustering patients with chronic hepatitis B virus infection

We previously found that genetic factors are associated with a familial predisposition for developing liver cirrhosis and hepatocellular carcinoma during chronic hepatitis B virus (HBV) infection. Autophagy has been shown to play a role in HBV replication and the course of disease. More than 190 host genes have been identified that modify the process of autophagy, but which of these genes are involved in chronicity of HBV infection and how this occurs remains unclear. Chronic hepatitis B (CHB) patients were recruited to investigate the expression of autophagy-modulating genes in peripheral blood mononuclear cells (PBMCs). mRNA prepared from PBMCs from members of two families with clustering HBV infection, including 11 CHB patients and nine healthy spouses, was hybridized to high-density oligonucleotide arrays. Immunoblot analysis was used to determine the level of autophagy. Of the 192 autophagy-modulating genes, 18 were found to be differently expressed. Of these, 11 displayed decreased expression in CHB patients, while seven displayed increased expression compared to those in healthy controls. Functional analysis showed that these genes are closely involved in initiation, nucleation, elongation of phagophores, formation of autophagosomes, transportation to lysosomes, and the process of degradation. Western blot analysis revealed inhibited autophagy in PBMCs based on decreased lipidation of LC3II. A differential expression profile of autophagy-modulating genes was observed, and decreased autophagy in PBMCs could be closely associated with chronicity of HBV infection, suggesting a novel strategy for the treatment of patients with chronic HBV infection.

5'-triphosphate siRNA targeting HBx elicits a potent anti-HBV immune response in pAAV-HBV transfected mice

RNA with 5'-triphosphate (3p-RNA) is recognized by RNA sensor RIG-I (retinoic acid-inducible gene I protein). Previously, we reported that small interfering RNA targeting HBx (3p-siHBx) could confer potent anti-hepatitis B virus (HBV) efficacy via HBx silencing and RIG-I activation. However, the characteristics of innate and adaptive immunity especially exhaustion profiles in the liver microenvironment in response to 3p-siHBx therapy have not been fully elucidated. Here, we observed that 3p-siHBx more significantly inhibited HBV replication in vivo. 3p-siHBx enhanced natural killer (NK) cell activation with KLRG1 and CD69 upregulation and interferon (IFN)-γ secretion. 3p-siHBx significantly reversed the exhaustion phenotype of CD8⁺ T cells, and augmented CD8⁺ T cell activation and function. Importantly, 3p-siHBx disrupted the differentiation of myeloid-derived suppressor cells (MDSC) and regulatory T cells (Treg), accompanied by the reduction of the immunosuppressive cytokines interleukin (IL)-10 and transforming growth factor (TGF)-β. 3p-siHBx also enhanced dendritic cell maturation. Further investigation showed that RIG-I was involved in 3p-siHBx-induced IFN-α, IFN-β, and IFN-λ production. Moreover, RIG-I activation in HBV⁺ hepatocytes would improve the recruitment of CD8⁺ T cells and NK cells. These results reveal that 3p-siHBx therapy can improve the immune microenvironment in HBV-carrier liver and inhibit HBV replication, indicating the potential utility of RIG-I ligands as molecular adjuvants for viral vaccines or candidate drugs.

DNA Vectors Generating Engineered Exosomes Potential CTL Vaccine Candidates Against AIDS, Hepatitis B, and Tumors

Eukaryotic cells constitutively produce nanovesicles of 50-150 nm of diameter, referred to as exosomes, upon release of the contents of multivesicular bodies (MVBs). We recently characterized a novel, exosome-based way to induce cytotoxic T lymphocyte (CTL) immunization against full-length antigens. It is based on DNA vectors expressing products of fusion between the exosome-anchoring protein Nef mutant (Nef^mut) with the antigen of interest. The strong efficiency of Nef^mut to accumulate in MVBs results in the production of exosomes incorporating huge amounts of the desired antigen. When translated in animals, the injection of Nef^mut-based DNA vectors generates engineered exosomes whose internalization in antigen-presenting cells induces cross-priming and antigen-specific CTL immunity. Here, we describe the molecular strategies we followed to produce DNA vectors aimed at generating immunogenic exosomes potentially useful to elicit a CTL immune response against antigens expressed by the etiologic agents of major chronic viral infections, i.e., HIV-1, HBV, and the novel tumor-associated antigen HOXB7. Unique methods intended to counteract intrinsic RNA instability and nuclear localization of the antigens have been developed. The success we met with the production of these engineered exosomes opens the way towards pre-clinic experimentations devoted to the optimization of new vaccine candidates against major infectious and tumor pathologies.

Seroprevalence of hepatitis B virus in Taiwan 30 years after the commencement of the national vaccination program

Background

In this study, the long-term efficacy of hepatitis B virus (HBV) vaccination was assessed using seroprevalence and an age–period–cohort (APC) model of HBV seromarkers among university entrants 30 years after the introduction of the national neonatal HBV vaccination program in Taiwan.

Methods

In total, data of 17,611 university entrants who underwent university entrance health examinations between 2005 and 2016 were included. The seroprevalence of the HBV surface antigen (HBsAg) and the levels of the antibody against the HBV surface antigen (anti-HBs) in each year group and sex were calculated. The levels of the antibody against the HBV core antigen were examined only for 2012 and 2016. The APC model was used to analyze the HBV carrier rates.

Results

The chronic HBV infection (HBsAg positivity) rate decreased from 9.7% in university students born before June 1974 to <1.0% in students born after 1992. The prevalence of anti-HBs positivity declined, particularly between the 1984–1988 cohort (78.2%–53.2%) and the 1990–1994 cohort (60.6%–44.4%). Our APC model revealed that the chronic HBV carrier rate among the student population was affected significantly by age, period, and cohort (P < 0.001).

Conclusions

HBV vaccination is one of the most effective strategies for preventing HBV infection. However, for complete eradication of HBV infection, the development of strategies that detect vaccination failure more effectively than current strategies do and early implementation of appropriate treatments are both necessary.

Delivery of Tapasin-modified CTL epitope peptide via cytoplasmic transduction peptide induces CTLs by JAK/STAT signaling pathway in vivo

Hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTLs) play a vital role in viral control and clearance. Recent studies have elucidated that Tapasin, an endoplasmic reticulum chaperone, is a well-known molecule that appears to be essential in peptide-loading process. The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway plays an important role in immune response regulation and cytokines secretion. We have previously verified that fusion protein CTP-HBcAg18-27-Tapasin could facilitate the maturation of bone marrow derived dendritic cells and enhance specific CTLs responses in vitro, which might be associated with the activation of JAK/STAT signaling pathway. To further explore whether JAK/STAT signaling pathway participated in specific immune responses mediated by CTP-HBcAg18-27-Tapasin, we suppressed the JAK/STAT pathway with pharmacological inhibitor (AG490) in vivo. Our studies showed that the number of IFN-γ+-CD8+ T cells was decreased significantly compared with other groups after being blocked by AG490. The percentage of IFN-γ+-CD4+ T cells and IL-2-CD4+ T cells was also decreased. Moreover, lower expression levels of Jak2, Tyk2, STAT1, and STAT4 were detected in AG490 group. In addition, the secretion levels of Th1-like cytokines were decreased and a weaker specific T-cell response was observed in AG490 group. Furthermore, the levels of HBV DNA and HBsAg in serum and expression levels of HBsAg and HBcAg in liver tissues were elevated after this pathway was inhibited in HBV transgenic mice. These results demonstrate that the JAK/STAT signaling pathway participates in Th1-oriented immune response induced by CTP-HBcAg18-27-Tapasin and this might provide a theoretical basis for HBV immunotherapy.

Distribution of peripheral dendritic cells in patients with HBV infection or spleen and kidney deficiency

Spleen and kidney deficiency syndrome (SKD), a Traditional Chinese Medicine (TCM) syndrome, is the fundamental mechanisms of TCM. We aim to investigate the distribution of peripheral dendritic cells (DCs) in HBV patients with SKD or non-SKD. Peripheral venous blood from patients with HBV infection and healthy volunteers was collected to extract PBMC, and flow cytometry assay was used to measure the distribution of DCs subsets, including myeloid dendritic cells (mDCs) and plasmacytoid dendritic cells (pDCs). For the number of pDCs, it was higher in control group and non-SKD group, compared with HBV infection group and SKD group, respectively. For the number of mDCs, it was higher in control group and the non-SKD group compared to SKD group, while in control group it was higher than both HBeAg positive group and negative group. The number of pDCs in control group and chronic hepatitis B group were higher than HBVcarrier group, and it was higher in control group than both immune tolerance group and inactive group, while in immune clearance group it was higher than immune tolerance group and inactve group. The number of mDCs in control group and immune clearance group were higher than that of immune tolerance group. There was an obvious correlation between TCM syndromes and immune function in HBV infected patients, the number of pDCs and mDCs of the SKD group was lower than that in non-SKD group. These results provide a new insight into scientific evidence that TCM probably be based.

Clinical significance of expression of TLR3 and TLR4 in liver tissue of patients with chronic hepatitis B

AIM

To investigate the correlation of the expression of Toll-like receptors 3 and 4 (TLR3, TLR4) with liver inflammation and liver fibrosis degree in the liver tissue of patients with chronic hepatitis B (CHB).

METHODS

One hundred and fifty-six CHB liver tissues obtained by liver biopsy were subjected to immunohistochemical staining for TLR3 and TLR4. Ten normal liver tissues served as controls. Then, immunohistochemical staining was quantified, and its correlation liver inflammatory activity and liver fibrosis degree was analyzed statistically.

RESULTS

TLR3 was strongly expressed in liver tissue of patients with CHB, mainly in the cytoplasm of liver cells and occasionally in the nucleus. The expression of TLR3 in liver tissue had a significant positive correlation with inflammation grade (r_s = 0.528, P < 0.01), and there was a significant linear relationship between them (χ² = 16.679, P < 0.01). The expression of TLR3 was also correlated with liver fibrosis degree (r_s = 0.510, P < 0.01), and there was a significant linear relationship between them (χ² = 16.654, P < 0.01). TLR4 was obviously expressed in liver cells, mainly in the cytoplasm and occasionally on cell membrane The expression of TLR4 had a significant positive correlation of liver fibrosis degree (r_s = 0.354, P < 0.01), and there was a significant linear relationship between them (χ² = 10.124, P < 0.05).

CONCLUSION

High expression of TLR3 and TRL4 is positively correlated with liver inflammation and liver fibrosis degree in CHB patients, suggesting that they might participate in the pathogenesis of CHB.

Identification of pro-inflammatory CD205+ macrophages in livers of hepatitis B virus transgenic mice and patients with chronic hepatitis B

Hepatic macrophages play a central role in disease pathogenesis during hepatitis B virus (HBV) infection. Our previous study found that CD205⁺ macrophages in the liver of hepatitis B surface antigen transgenic (HBs-Tg) mice increased significantly compared with those in wild-type mice, and these increased CD205⁺ macrophages were involved in CpG-oligodeoxynucleotide-induced liver injury in HBs-Tg mice. Here, we analysed the phenotype and function of CD205⁺ macrophages derived from the liver of HBs-Tg mice and patients with chronic hepatitis B (CHB). We found that HBs-Tg mice-derived hepatic macrophages produced larger amounts of pro-inflammatory cytokines, including IL-6, IL-12, TNF-α, and of the anti-inflammatory cytokine IL-10 after stimulation with CpG-oligodeoxynucleotides or commensal bacteria DNA than B6 mice-derived hepatic macrophages. Furthermore, hepatic CD205⁺ macrophages from HBs-Tg mice showed an activated phenotype and expressed higher levels of inflammatory cytokine genes, chemokine genes, and phagocytosis-related genes than hepatic CD205⁻ macrophages. In addition, CD205⁺ macrophages displayed an inflammatory phenotype and were increased in the liver of patients with CHB compared with those in healthy controls. Our data suggest that hepatic CD205⁺ macrophages are a unique pro-inflammatory subset observed during HBV infection. Thus, development of intervention targeting these cells is warranted for immunotherapy of HBV-induced liver diseases.

Symbiotic chemo- and immuno-therapy for hepatitis B and C viruses

Hepatitis B and C viruses (HBV and HCV), both cause serious chronic infections leading to fatal liver diseases. The prototype therapy for both HBV and HCV was based on IFN-α with or without ribavirin. The advent of direct-acting antivirals (DAA) for both HBV and HCV has remarkably improved the standard of treatment for both infections. While HCV can be eliminated following combination DAA therapy, HBV persists even after treatment, requiring life-long therapy with DAAs. Treatment with DAAs is also associated with high cost, the development of resistance and side effects. There is ample published evidence that both HBV and HCV can be eliminated from infected host cells through non-cytolytic immune mechanisms. We need to identify the mechanisms behind this successful elimination of replicating viruses and develop them into novel immunotherapeutic regimens. Moreover, a synergy of, chemo- and immuno-therapeutic strategies will be necessary to eradicate HBV or HCV from a host.