Impact of HBeAg on the maturation and function of dendritic cells

Cytokine profiles and CD8+ T cells in the occurrence of acute and chronic hepatitis B

OBJECTIVE

We explore the expression of functional molecules on CD8+ T lymphocytes, cytokines concentration, and their correlation to occurrence of hepatitis B and hepatitis B virus (HBV) desoxyribose nucleic acid (DNA), hepatitis B surface antigen (HBsAg), hepatitis B envelope antigen (HBeAg), and alanine aminotransferase (ALT) in patients infected with HBV.

METHODS

This is a single center study. 32 patients with acute hepatitis B (AHB), 30 patients with immune tolerant (IT) phase chronic HBV infected, and 50 patients with chronic hepatitis B (CHB) were enrolled. The activation molecules (CD69) and the apoptosis-inducing molecules (CD178) on surface of CD8+ T lymphocytes were tested by the flow cytometry. Fms-like tyrosine kinase 3 ligand (Flt-3L), interleukin 17A (IL-17A), interferon γ (IFN-γ), and Interferon α2 (IFN-α2) were quantitated by Luminex assay. We use linear regression analysis to analyze their correlations to ALT, HBV DNA, HBsAg, and HBeAg.

RESULTS

The frequency of CD69+CD8+ T lymphocytes in CHB and AHB groups were increased significantly compared with IT group (4.19[3.01, 6.18]% and 4.45[2.93, 6.71]% vs. 3.02[2.17, 3.44]%; H=26.207, P=0.001; H=28.585, P=0.002), and the mean fluorescence intensity (MFI) of CD69 in AHB group was significantly higher than IT and CHB groups (27.35[24.88, 32.25] vs. 20.45[19.05, 27.75] and 23.40[16.78, 28.13]; H=25.832, P=0.005 and H=22.056, P=0.008). In IT group, HBsAg levels and HBV DNA loads were negatively correlated with CD69MFI (β=-0.025, t=-2.613, P=0.014; β=-0.021, t=-2.286, P=0.030), meanwhile, HBeAg was negatively related to the frequency of CD69+CD8+ T lymphocytes (β=-61.306, t=-2.116, P=0.043). In AHB group, IFN-α2 was positively related to the frequency of CD8+ T lymphocytes (β=6.798, t=2.629, P=0.016); however, in CHB group, IFN-α2 was negatively associated with frequency of CD8+ T lymphocytes (β=-14.534, t=-2.085, P=0.043). In CHB group, HBeAg was positively associated with frequency of CD69+CD8+ T lymphocytes (β=43.912, t=2.027, P=0.048). In AHB group, ALT was positively related to CD69MFI (β=35.042, t=2.896, P=0.007), but HBsAg was negatively related to CD178MFI (β=-0.137, t=-3.273, P=0.003).

CONCLUSIONS

The activation of CD8+ T lymphocytes was associated with the occurrence of AHB and CHB. However, due to the insufficient expression of functional molecules of CD8+ T lymphocytes and the depletion of CD8+ T lymphocytes, CHB patients were difficult to recover from HBV infection.

Innate and adaptive immune escape mechanisms of hepatitis B virus

Chronic hepatitis B virus (HBV) infection is an international health problem with extremely high mortality and morbidity rates. Although current clinical chronic hepatitis B (CHB) treatment strategies can partly inhibit and eliminate HBV, viral breakthrough may result due to non-adherence to treatment, the emergence of viral resistance, and a long treatment cycle. Persistent CHB infection arises as a consequence of complex interactions between the virus and the host innate and adaptive immune systems. Therefore, understanding the immune escape mechanisms involved in persistent HBV infection is important for designing novel CHB treatment strategies to clear HBV and achieve long-lasting immune control. This review details the immunological and biological characteristics and escape mechanisms of HBV and the novel immune-based therapies that are currently used for treating HBV.

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.

Association of cytokines with hepatitis B virus and its antigen

To investigate the characteristics of cytokines in patients with different HBV infection status and their correlation with HBV DNA, HBsAg, and HBeAg levels. Peripheral blood samples were collected from patients with chronic HBV infection in immune tolerance phase (IT), HBeAg-positive chronic hepatitis B (CHB), and acute hepatitis B (AHB) groups, and levels of cytokines were detected by Luminex technique, and analyzed by FLEXMAP 3D analyzer. The correlation between cytokines and HBV DNA load, HBsAg, HBeAg, and alanine aminotransferase (ALT) level in patients with chronic HBV infection was analyzed. In total 312 subjects (184 males and 128 females) were enrolled in the study. There were significant differences among IT, CHB, and AHB groups in Flt-3L value (P = .003; H = 12.312), IFN-γ (P = .001; H = 11.723), IL-10 (P = .001; H = 18.736), IL-17A ((P = .001; H = 12.735), and TGF-β1 (P = .001; Z = 48.571). IFN-α2 levels in CHB group were significantly higher than those in IT and AHB groups (15.24 vs 35.78 pg/mL, P = .000; Z = 3.727; 13.88 vs 35.78 pg/mL, P = .024; Z = -2.258. In CHB group, the levels of HBsAg and ALT were positively correlated with the levels of IL-10 (r = .173; P = .006; r = 0.176; P = .006, respectively), while HBeAg level was positively correlated with the IFN-α2 level (r = .153; P = .016). In AHB group, the HBsAg level was positively correlated with Flt-3L, IFN-α2, IL-10, and IL-6 (r = .402; P = .023; r = .436; P = .016; r = .524, P = .002; r = .405; P = .022, respectively). HBeAg level was positively correlated with IFN-γ and IL-17A levels (r = .400; P = .023; r = .373; P = .036, respectively), and ALT level was positively correlated with IL-6 levels (r = .367; P = .039). In either AHB or CHB group, HBV DNA load was only related to TGF-β level (r = .493; P = .004; r = -.218, P = 0.009 respectively). The correlation between Flt-3L and HBsAg (F = 7.422; P = .007); IL-17, IL-6, and HBeAg (F = 5.757; P = .017; F = 6.156; P = .014) were statistically significant. There was significant correlation between TGF-β2 and HBV DNA (F = 11.795; P = .001), and between ALT and HBsAg, HBV DNA (F = 26.089; P = .000; F = 4.724; P = .031). HBsAg, HBeAg, and HBV DNA were correlated with cytokines and ALT in patients with HBV infection. The level of IFN-α2 was significantly higher in patients with CHB. HBV DNA load was only correlated with the level of TGF-β in acute or CHB.

In vitro effects of 5 recombinant antigens of Eimeria maxima on maturation, differentiation, and immunogenic functions of dendritic cells derived from chicken spleen

Eimeria maxima possesses integral families of immunogenic constituents that promote differentiation of immune cells during host-parasite interactions. Dendritic cells (DCs) have an irreplaceable role in the modulation of the host immunity. However, the selection of superlative antigen with immune stimulatory efficacies on host DCs is lacking. In this study, 5 recombinant proteins of E. maxima (Em), including Em14-3-3, rhomboid family domain containing proteins (ROM) EmROM1 and EmROM2, microneme protein 2 (EmMIC2), and Em8 were identified to stimulate chicken splenic derived DCs in vitro. The cultured populations were incubated with recombinant proteins, and typical morphologies of stimulated DCs were obtained. DC-associated markers major histocompatibility complex class II, CD86, CD11c, and CD1.1, showed upregulatory expressions by flow cytometry assay. Immunofluorescence assay revealed that recombinant proteins could bind with the surface of chicken splenic derived DCs. Moreover, quantitative real-time PCR results showed that distinct gene expressions of Toll-like receptors and Wnt signaling pathway were upregulated after the coincubation of recombinant proteins with DCs. The ELISA results indicated that the DCs produced a significant higher level of interleukin (IL)-12 and interferon-γ secretions after incubation with recombinant proteins. While transforming growth factor-β was significantly increased with rEmROM1, rEmROM2, and rEmMIC2 as compared to control groups, and IL-10 did not show significant alteration. Taken together, these results concluded that among 5 potential recombinant antigens, rEm14-3-3 could promote immunogenic functions of chicken splenic derived DCs more efficiently, which might represent an effective molecule for inducing the host Th1-mediated immune response against Eimeria infection.

T Cells in Viral Infections: The Myriad Flavours of Antiviral Immunity

Viral diseases are a major cause of morbidity and mortality and result in a significant public health burden. T lymphocytes first identified in the chordate lineage and constitute a highly sophisticated branch of adaptive immune system. Apart from B cells, it is the only cell type that exhibits antigenic specificities; achieved by gene rearrangement. T cells are unique with respect to diversity of their subsets, which have distinct effector specificities, proliferative abilities, memory generation, and life span. T cells are impactful in viral infections by virtue of their capability to combat intracellular pathogens. The effector functions of T cells are mediated through cytokines/chemokines and by direct cytotoxicity of infected cells. T cell response can be beneficial or detrimental to host; prognosis depending on qualitative and quantitative differences in the response. Persistent viral infections are associated with functionally suboptimal, exhausted T cell responses, which are unable to clear virus. Specific subsets such as regulatory T cells (Tregs) dampen antiviral responses; thereby favouring viral persistence. However, Tregs protect the host from immunopathology by limiting perpetual inflammation. Certain other subsets such as Th17 cells may contribute to autoimmune component of viral infections. The importance of T cells is highlighted by the fact that modern vaccination and therapeutic approaches focus on modulating T cell frequencies and effector functions. This chapter emphasises the understanding how T cells influence outcomes of viral infections, modern vaccination and therapeutic strategies with thrust on T cell biology.

Predictors of sustained functional cure in hepatitis B envelope antigen-negative patients achieving hepatitis B surface antigen seroclearance with interferon-alpha-based therapy

Hepatitis B surface antigen (HBsAg) loss is considered a functional cure in chronic hepatitis B (CHB). However, the durability of HBsAg loss after stopping treatment remains unknown. This study aimed to assess the sustained functional cure achieved by interferon therapy in hepatitis B envelope antigen (HBeAg)-negative CHB patients. In this prospective study, 176 HBeAg-negative CHB patients with functional cure were enrolled for 12 weeks of cessation treatment, and treatment information and baseline data were collected. Hepatitis B virus (HBV) biomarkers and clinical biochemical indicators were evaluated every 3 months; liver imaging examinations were performed every 3-6 months during the 48-week follow-up. The sustained functional cure was evaluated. After the 48-week follow-up, the sustained functional cure rate was 86.63%. The cumulative rates of HBsAg reversion and HBV DNA reversion were 12.79% and 2.33%, respectively. Consolidation treatment ≥ 12 weeks after HBsAg loss achieved a significantly higher rate of sustained functional cure and significantly lower rate of HBsAg reversion than consolidation treatment < 12 weeks (76.19% vs 90.00%, P = 0.022 and 23.81% vs 9.23%, P = 0.014, respectively). Patients with hepatitis B surface antibody (HBsAb) had higher rate of sustained functional cure than patients achieving HBsAg loss but without HBsAb (89.86% vs 73.53%, P = 0.012). Consolidation treatment ≥ 12 weeks (odds ratio [OR] 16.478; 95% confidence interval [CI], 2.135-127.151; P = 0.007) and high HBsAb levels (OR 8.312; 95% CI, 1.824-37.881; P = 0.006) were independent predictors of sustained functional cure. Results suggested that 12 weeks of consolidation therapy after HBsAg clearance and elevated HBsAb levels help to improve functional cure.

Plasmacytoid Dendritic Cell Function and Cytokine Network Profiles in Patients with Acute or Chronic Hepatitis B Virus Infection

Background:

Plasmacytoid dendritic cells (pDCs) and cytokines play an important role in occurrence and recovery of hepatitis B virus (HBV) infection. The aim of this study was to explore the frequency and function of pDC and serum cytokine network profiles in patients with acute or chronic HBV infection.

Methods:

The healthy individuals (HI group), hepatitis B envelope antigen (HBeAg)-positive chronic HBV patients in immune tolerance (IT) phase (IT group), HBeAg-positive chronic HBV patients (CHB group), and acute HBV patients (AHB group) were enrolled in this study. The frequency of cluster of differentiation antigen 86 (CD86) + pDC and the counts of CD86 molecular expressed on surface of pDC were tested by flow cytometer. The quantitative determinations of cytokines, including Fms-like tyrosine kinase 3 ligand (Flt-3L), interferon (IFN)-α2, IFN-γ, interleukin (IL)-17A, IL-6, IL-10, transforming growth factor (TGF)-β1 and TGF-β2, were performed using Luminex multiplex technology.

Results:

In this study, there were 13 patients in HI group, 30 in IT group, 50 in CHB group, and 32 in AHB group. Compared with HI group, HBV infected group (including all patients in IT, CHB and AHB groups) had significantly higher counts of CD86 molecular expressed on the surface of pDC (4596.5 ± 896.5 vs. 7097.7 ± 3124.6; P < 0.001). The counts of CD86 molecular expressed on the surface of pDC in CHB group (7739.2 ± 4125.4) was significantly higher than that of IT group (6393.4 ± 1653.6, P = 0.043). Compared with IT group, the profile of cytokines of Flt-3L, IFN-γ, and IL-17A was decreased, IFN-α2 was significantly increased (P = 0.012) in CHB group. The contents of IL-10, TGF-β1, and TGF-β2 in AHB group were significantly increased compared with IT and CHB groups (all P < 0.05).

Conclusions:

This study demonstrated that the function of pDC was unaffected in HBV infection. The enhanced function of pDC and IFN-α2 might involve triggering the immune response from IT to hepatitis active phase in HBV infection. Acute patients mainly presented as down-regulation of the immune response by enhanced IL-10 and TGF-β.

Association of Cytokines with Alanine Aminotransferase, Hepatitis B Virus Surface Antigen and Hepatitis B Envelope Antigen Levels in Chronic Hepatitis B

Background

Cytokines play an important role in occurrence and recovery of hepatitis B virus (HBV) infection. The aim of this study was to investigate the changes of cytokines concentration and its correlation to alanine aminotransferase (ALT), HBV deoxyribonucleic acid (HBV-DNA), hepatitis B envelope antigen (HBeAg), and HBV surface antigen (HBsAg) in the development of chronic hepatitis B (CHB).

Methods

Thirteen healthy individuals (HI), 30 chronic HBV-infected patients in immune tolerant (IT) phase, and 55 CHB patients were enrolled between August 2015 and May 2017. The peripheral blood samples were collected from all individuals. The levels of interferon (IFN)-α2, interleukin (IL)-10, transforming growth factor (TGF)-β1, HBV-DNA, HBsAg, and HBeAg and liver function were measured. The quantitative determinations of cytokines levels, including IFN-α2, IL-10, and TGF-β1 were performed using Luminex multiplex technology. The correlation of cytokines to ALT, HBV-DNA, HBsAg, and HBeAg was analyzed by linear regression analysis.

Results

IFN-α2 levels were similar between HI and IT groups (15.35 [5.70, 67.65] pg/ml vs. 15.24 [4.07, 30.73] pg/ml, Z = -0.610, P = 0.542), while it elevated significantly in CHB group (35.29 [15.94, 70.15] pg/ml vs. 15.24 [4.07, 30.73] pg/ml; Z = -2.522, P = 0.012). Compared with HI group (3.73 [2.98, 11.92] pg/ml), IL-10 concentrations in IT group (5.02 [2.98, 10.11] pg/ml), and CHB group (7.48 [3.10, 18.00] pg/ml) slightly increased (χ² = 2.015, P = 0.365), and there was no significant difference between IT and CHB group (Z = -1.419, P = 0.156). The TGF-β1 levels among HI (3.59 ± 0.20 pg/ml), IT (3.62 ± 0.55 pg/ml), and CHB groups (3.64 ± 0.30 pg/ml) were similar (χ² = 2.739, P = 0.254). In all chronic HBV-infected patients (including patients in IT and CHB groups), the elevation of IFN-α2 level was significantly associated with ALT level (β= 0.389, t = 2.423, P = 0.018), and was also negatively correlated to HBV-DNA load (β = -0.358, t = -2.308, P = 0.024), HBsAg (β = -0.359, t = -2.288, P = 0.025), and HBeAg contents (β = -0.355, t = -2.258, P = 0.027). However, when both ALT level and cytokines were included as independent variable, HBV-DNA load, HBsAg, and HBeAg contents were only correlated to ALT level (β = -0.459, t = -4.225, P = 0.000; β = -0.616, t = -6.334, P = 0.000; and β = -0.290, t = -2.433, P = 0.018; respectively).

Conclusions

IFN-α2 elevation was associated with ALT level in patients with chronic HBV infection. However, in CHB patients, only ALT level was correlated to HBV-DNA, HBsAg and HBeAg contents.

Liver-Targeted Anti-HBV Single-Stranded Oligonucleotides with Locked Nucleic Acid Potently Reduce HBV Gene Expression In Vivo

Chronic hepatitis B infection (CHB) is an area of high unmet medical need. Current standard-of-care therapies only rarely lead to a functional cure, defined as durable hepatitis B surface antigen (HBsAg) loss following treatment. The goal for next generation CHB therapies is to achieve a higher rate of functional cure with finite treatment duration. To address this urgent need, we are developing liver-targeted single-stranded oligonucleotide (SSO) therapeutics for CHB based on the locked nucleic acid (LNA) platform. These LNA-SSOs target hepatitis B virus (HBV) transcripts for RNase-H-mediated degradation. Here, we describe a HBV-specific LNA-SSO that effectively reduces intracellular viral mRNAs and viral antigens (HBsAg and HBeAg) over an extended time period in cultured human hepatoma cell lines that were infected with HBV with mean 50% effective concentration (EC₅₀) values ranging from 1.19 to 1.66 μM. To achieve liver-specific targeting and minimize kidney exposure, this LNA-SSO was conjugated to a cluster of three N-acetylgalactosamine (GalNAc) moieties that direct specific binding to the asialoglycoprotein receptor (ASGPR) expressed specifically on the surface of hepatocytes. The GalNAc-conjugated LNA-SSO showed a strikingly higher level of potency when tested in the AAV-HBV mouse model as compared with its non-conjugated counterpart. Remarkably, higher doses of GalNAc-conjugated LNA-SSO resulted in a rapid and long-lasting reduction of HBsAg to below the detection limit for quantification, i.e., by 3 log10 (p < 0.0003). This antiviral effect depended on a close match between the sequences of the LNA-SSO and its HBV target, indicating that the antiviral effect is not due to non-specific oligonucleotide-driven immune activation. These data support the development of LNA-SSO therapeutics for the treatment of CHB infection.

Hepatitis B virus infection and the immune response: The big questions

Clinical events and the host immune response during hepatitis B virus (HBV) infection are intricately linked. Despite decades of research, important questions concerning the immunopathogenesis of chronic HBV infection remain unanswered. For example, it is unclear which immune parameters facilitate persistence, and if HBV can be completely cleared from the human liver. Recent technological breakthroughs now allow researchers to address these seemingly basic, but essential questions surrounding HBV immunity. It will be important to better define the molecular underpinnings of immune cell function and dysfunction during chronic disease and in controlled infection, with particular focus on the liver, as little information is available on the intrahepatic compartment. In the near future, it may be possible to solve some of the controversy surrounding the immune responses to HBV, and establish the features of both the innate and adaptive arms of the immune system required to achieve sustained control of HBV infection.

Synthesis of stable isotopically labeled peptides with filter-assisted enzymatic labeling for the diagnosis of hepatitis B virus infection utilizing mass spectrometry-based proteomics strategy

A facile method for the preparation of stable isotopically labeled peptides was developed by means of filter-assisted tryptic ¹⁶O/¹⁸O water labeling, which could be directly applied to the determination of hepatitis B virus infection from human serum with tandem mass spectrometry. Tryptic peptides of hepatitis B surface antigen or hepatitis B e antigen from different subtypes of hepatitis B virus were synthesized with traditional solid-phase peptide synthesis as potential biomarkers. Trypsin catalyzed oxygen-18 exchange at their amidated c-terminus of arginine or lysine residue. The protease catalyzed oxygen-18 to oxygen-16 back exchange reaction was eliminated due to the complete removal of trypsin by the centrifugal filter containing a thin membrane associated with molecular weight cut-off of 10 KDa. The synthetic isotopic peptides were spiked into trichloroacetic acid/acetone precipitated human serum as internal standards and were selectively detected with multiplexed parallel reaction monitoring on a hybrid quadrupole-orbitrap mass spectrometer. The limit of detection for all synthetic peptides were in the range of 0.09 fmol-1.13 fmol. The results indicated that the peptide YLWEWASVR derived from hepatitis B surface antigen was quantified approximately 200 fmol per μl serum and may serve as a diagnostic biomarker for the detection of hepatitis B virus infected disease.