The high prevalence of the I27 mutant HBcAg18-27 epitope in Chinese HBV-infected patients and its cross-reactivity with the V27 prototype epitope

Impact of core protein naturally selected mutants associated with HBeAg-negative status in HBV biosynthesis

Hepatitis B e antigen (HBeAg) loss represents a late stage of chronic hepatitis B virus (HBV) infection associated with a drastic decrease in HBV-DNA, a lower risk of disease progression, and the occurrence of several mutations in the preCore/core region. However, the underlying mechanisms supporting the downregulation of viral replication have yet to be elucidated. In the present study, the analysis of the frequency of subgenotype D1 core protein (HBc) mutations associated with HBeAg status revealed a higher mutation rate in HBeAg-negative sequences compared to HBeAg-positive ones. Particularly, 22 amino acids exhibited a higher frequency of mutation in HBeAg-negative sequences, while the remaining residues showed a high degree of conservation. Subsequently, the assessment of HBc mutants derived from HBeAg-negative patients in viral structure and replicative capacity revealed that HBc mutations have the ability to modulate the subcellular localization of the protein (either when the protein was expressed alone or in the context of viral replication), capsid assembly, and, depending on specific mutation patterns, alter covalently closed circular DNA (cccDNA) recycling and up- or downregulate viral replication. In conclusion, HBc mutations associated with HBeAg-negative status impact on various stages of the HBV life cycle modulating viral replication during the HBeAg-negative stage of infection.

Depression Is Associated with Downregulation of IPS-1 in Chronic HBV-Infected Patients in a Sex-Dependent Manner

BACKGROUND

Depression and anxiety can modulate immune-related molecule expressions. The chronic HBV-infected (CHB) patients suffer from inappropriate immune responses. Additionally, psychological disorders are prevalent among the patients. Thus, depression and anxiety may alter immune-related molecule expression. This study aimed to examine IPS-1 and RIP1 mRNA levels in CHB patients suffering from various degrees of anxiety and depression.

METHODS

Sixty patients with CHB participated in this research and completed standard questionnaires to evaluate depression and anxiety. The expression levels of IPS-1 and RIP1 were examined using real-time PCR techniques.

RESULTS

The result revealed that although the expression of IPS-1 and RIP1 did not change in the CHB patients with various ranges of depression and anxiety, IPS-1 was significantly decreased in the male CHB patients who suffered from mild, moderate, and severe depression when compared to the patients with no depression.

CONCLUSION

So, it was hypothesized that depression may be associated with alteration in the expression of IPS-1 in a sex-dependent manner. In other words, it appears that the male CHB patients are at risk of depression-related alteration in immune-related gene expression.

Ex vivo Detection and Characterization of Hepatitis B Virus-Specific CD8+ T Cells in Patients Considered Immune Tolerant

In this study, we aimed to detect and characterize ex vivo virus-specific CD8⁺ T cells in patients with immune-tolerant hepatitis B virus (HBV) infection. We investigated a Korean chronic hepatitis B cohort composed of 15 patients in the immune-tolerant phase, 17 in the immune-active phase, and 13 under antiviral treatment. We performed enzyme-linked immunospot (ELISpot) assays ex vivo and intracellular cytokine staining after in vitro culture. We also performed ex vivo multimer staining assays and examined the expression of programmed death-1 (PD-1) and CD127 in pentamer-positive cells. Ex vivo ELISpot revealed that HBV-specific T cell function was weaker in immune-tolerant patients than in those under antiviral treatment. In vitro culture of peripheral blood mononuclear cells for 10 days revealed that HBV-specific CD8⁺ T cells produced interferon-γ in some immune-tolerant patients. We detected HBV-specific CD8⁺ T cells ex vivo (using the HBV core_18-27 pentamer) in patients from all three groups. The PD-1⁺ subset of pentamer⁺ CD8⁺ T cells was smaller ex vivo in the immune-tolerant phase than in the immune-active phase or under antiviral treatment. Interestingly, the proportion of PD-1⁺ CD8⁺ T cells in HBV-specific CD8⁺ T cells correlated with patient age when all enrolled patients were analyzed. Overall, HBV-specific CD8⁺ T cells are present in patients considered as immune-tolerant, although their ex vivo functionality is significantly weaker than that in patients under antiviral treatment (P < 0.05). Despite the high viral load, the proportion of PD-1 expression in HBV-specific CD8⁺ T cells is lower in the immune-tolerant phase than in other phases. Our results indicate appropriate stimulation may enhance the effector function of HBV-specific CD8⁺ T cells in patients considered as being in the immune-tolerant phase.

Serum Levels of IL-6, IL-8, TNF-α, and TGF-β in Chronic HBV-Infected Patients: Effect of Depression and Anxiety

Objective

To assess the effects of depression and anxiety on serum cytokine levels in patients with chronic hepatitis B (CHB) infection.

Methods

In this cross-sectional study, 60 healthy control individuals and 60 patients with CHB participated after filling out standard questionnaires. We examined their serum interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, and TGF-β levels using enzyme-linked immunosorbent assay (ELISA) techniques.

Results

In patients with CHB compared with healthy controls, serum levels of IL-8 were significantly increased, whereas IL-6 and TGF-β levels were significantly decreased. Serum levels of TGF-β were significantly decreased in the patients with CHB who had mild depression, compared with patients with CHB without depression and with moderate and severe depression.

Conclusions

Downregulation of IL-8 and TGF-β, respectively, is a corresponding mechanism for induction of chronic inflammation in patients with CHB. Depression also seems to induce inflammation via downregulation of TGF-β in these patients.

Evaluation of NLRC4, NLRP1, and NLRP3, as Components of Inflammasomes, in Chronic Hepatitis B Virus-Infected Patients

Nucleotide-binding domain leucine repeats (NLRs) are required for the recognition of various molecules that are expressed within microbes and are able to actuate appropriate immune responses via activation of cytokines. The current study evaluates the expression levels of NLRP1 and NLRC4, which are components of inflammasomes, in chronic hepatitis B (CHB) virus-infected patients. This study recruited two series of CHB patients (each contained 60 patients) and 60 healthy controls. Real-time polymerase chain reaction (PCR) was employed to evaluate mRNA expression levels of NLRP1, NLRP3, and NLRC4 as well as hepatitis B virus (HBV)-DNA copy number. Serum levels of liver markers were also used to evaluate the patients. Hepatitis B envelope antigen (HBeAg) and hepatitis B surface antigen (HBsAg) were also examined in all patients to evaluate infection. The data showed that expression levels of NLRC4 and NLRP1 were not significantly different in circulating monocytes of CHB patients when compared with those of healthy controls. Furthermore, the data indicate that mRNA levels of NLRP1, NLRP3, and NLRC4 were also not altered in CHB patients regardless of HBV-DNA copy numbers/mL and HBeAg status. The data revealed that mRNA expression levels of NLRP1 and NLRC4 were not altered in CHB patients, suggesting that these genes are not responsible for the impaired immune responses against HBV observed in these patients.

Anxiety leads to up-regulation of CD36 on the monocytes of chronic hepatitis B-infected patients

Introduction It has been hypothesized that mental disorders including depression and anxiety can affect immune responses. The study was done to evaluate the relation between depression and anxiety and expression levels of CD36, CD68, and CD9 on peripheral blood monocytes of chronic hepatitis B (CHB) patients. Methods Sixty CHB patients were selected with various ranges of depression and anxiety. Depression and anxiety were evaluated using a standard questionnaire by an expert psychiatrist according to BECK's Depression Inventory II and Hamilton Anxiety Rating Scale, respectively. The levels of CD36, CD68, and CD9 on the peripheral blood monocytes have been performed using flow cytometry technique. Results The results demonstrated that levels of CD36 were significantly increased on the peripheral blood monocytes of CHB patients when compared with CHB patients with no anxiety. Expression levels of CD68 and CD9 were not significantly altered on the CHB patients with various ranges of anxiety. Expression levels of CD36, CD68, and CD9 were also not significantly altered on the CHB patients with various ranges of depression. Discussion It seems that anxiety induces inflammation in the CHB patients by induction of alteration in several molecules including up-regulation of CD36. CD36 plays important roles in the induction of tissue damage; hence, it may be hypothesized that anxiety may participate in the induction of some hepatitis B complications.

Mechanism for cytoplasmic transduction peptide-HBcAg18-27-Tapasin to induce HBV specific CTL response in C57BL/6 mice

AIM: To observe whether the fusion protein cytoplasmic transduction peptide (CTP) -HBcAg_18-27-Tapasin can induce HBV-specific cytotoxic T lymphocyte (CTL) response in C57BL/6 mice via the JAK / STAT pathway.

METHODS: C57BL/6 mice were randomly divided into four groups: CTP-HBcAg_18-27-Tapasin alone group, CTP-HBcAg_18-27-Tapasin + AG490 group, AG490 alone group, and PBS group. Mice were immunized with the fusion protein through intramuscular injection, and AG490 was administered through intraperitoneal injection. The proliferation of T lymphocytes was observed using CCK-8 assay. The levels of the cytokines secreted by T lymphocytes were detected by ELISA, and the levels of intracellular cytokines of proliferative T lymphocytes were detected by flow cytometry. Expression levels of molecules of the JAK/STAT signal pathway were detected by real-time PCR.

RESULTS: The percentage of CD8⁺IFN-γ⁺ T cells, T lymphocytes proliferative activity and the levels of Th1 cytokines in the CTP-HBcAg_18-27-Tapasin alone group were significantly increased compared with the CTP-HBcAg_18-27-Tapasin + AG490 group (P < 0.01), although there was no statistical significance between the other groups. The expression levels of Jak2 and STAT4 were significantly higher in the CTP-HBcAg_18-27-Tapasin alone group than the rest groups (P < 0.05), and the expression levels of Tyk2 and STAT1 were also dramatically increased in the CTP-HBcAg_18-27-Tapasin alone group compared to other groups (P < 0.01).

CONCLUSION: CTP-HBcAg_18-27-Tapasin fusion protein increases HBV-specific CTL response via the JAK/STAT signal pathway in C57BL/6 mice.

Intensity of HLA-A2 Expression Significantly Decreased in Occult Hepatitis B Infection

Background:

Occult hepatitis B infected (OBI) patients cannot eradicate hepatitis B virus (HBV)-DNA from their liver and peripheral blood, completely.

Objectives:

The main aim of this study was to investigate the rate of HLA-A2 expression on peripheral blood mononuclear cells (PBMCs) of patients with OBI.

Materials and Methods:

In this experimental study, intensity of HLA-A2 was measured on the PBMCs of 57 OBI patients and 100 HBsAg-/anti-HBc+/HBV-DNA samples were enrolled as controls; measurements were performed using the flow cytometry technique.

Results:

Flow cytometric analysis indicated that 19 (33.3%) OBI patients and 28 (28%) controls expressed HLA-A2 antigen on their PBMCs. There was no significant difference between the two groups regarding the rate of individuals expressing HLA-A2 antigen. Statistical analyses showed that the intensity of HLA-A2 expression significantly decreased in OBI patients (3.58 ± 0.1) in comparison to healthy controls (4.21 ± 0.25; P < 0.001).

Conclusions:

According to these results it can be concluded that decreased intensity of HLA-A2 on the PBMCs of OBI patients may lead to resistance of HBV in the patients.

CCR5 on the NK Cells and its Ligand (RANTES) Expressions are Disrupted in South-Eastern Iranian Patients With Chronic Hepatitis B Infection

Background:

CCR5 is a receptor for CCL3 (MIP-1 α), CCL4 (MIP-1 α) and CCL5 (regulated on activation normal T cell expressed and secreted (RANTES)) and play important roles in recruitment of NK cells to the HBV infected liver.

Objectives:

The main purpose of this study was to investigate the expression levels of CCR5 on the NK cells and also serum levels of RANTES in chronic HBV infected (CHI) patients.

Materials and Methods:

In this descriptive study 63 CHI patients and 96 healthy controls were evaluated regarding CCR5 expression on the NK cells and serum levels of RANTES using flow cytometry and ELISA techniques, respectively. Real-Time PCR technique also was used for HBV-DNA quantification.

Results:

The results revealed that CCR5 expressing NK cells and serum levels of RANTES were decreased significantly in the CHI patients in compare to healthy control.

Conclusions:

Based on the results it can be concluded that NK cells of Iranian CHI patients are unable to express adequate levels of CCR5 and expression levels of RANTES by immune cells also are defected in CHI patients, hence, the migration of NK cells to the infected hepatocytes and HBV eradication from the cells is interrupted.

Characterization of a soluble B7-H3 (sB7-H3) spliced from the intron and analysis of sB7-H3 in the sera of patients with hepatocellular carcinoma

B7-H3 is a recently discovered member of the B7 superfamily molecules and has been found to play a negative role in T cell responses. In this study, we identified a new B7-H3 isoform that is produced by alternative splicing from the forth intron of B7-H3 and encodes the sB7-H3 protein. Protein sequence analysis showed that sB7-H3 contains an additional four amino acids, encoded by the intron sequence, at the C-terminus compared to the ectodomain of 2Ig-B7-H3. We further found that this spliced sB7-H3 plays a negative regulatory role in T cell responses and serum sB7-H3 is higher in patients with hepatocellular carcinoma (HCC) than in healthy donors. Furthermore, we found that the expression of the spliced sb7-h3 gene is higher in carcinoma and peritumor tissues than in PBMCs of both healthy controls and patients, indicating that the high level of serum sB7-H3 in patients with HCC is caused by the increased expression of this newly discovered spliced sB7-H3 isoform in carcinoma and peritumor tissues.

Decreased expression of toll like receptor signaling molecules in chronic HBV infected patients

INTRODUCTION

Toll like receptors (TLRs) and their signaling molecules play important roles in microbe recognition and induction of immune responses, including production of inflammatory cytokines, against viral infections. Therefore, the aim of this study was to examine expression levels of TLR signaling molecules (IRAK1, IRAK4, TRAF3, and IRF7) and the pro-inflammatory cytokines, IL-12 and IL-6 in chronic HBV infected (CHB) patients.

DESIGN

This study was performed on 60 CHB patients and 60 healthy controls and the expression of IRAK1, IRAK4, TRAF3, and IRF7 and their downstream inflammatory cytokines (IL-12 and IL-6) were evaluated by Real-Time PCR and ELISA techniques.

RESULTS

The results demonstrated that expression of IRAK4, TRAF3, and IRF7 were significantly decreased in PBMCs of CHB patients in comparison to healthy controls. Serum levels of IL-12 were significantly increased, while, IL-6 were not differ between patients and controls.

CONCLUSIONS

Based on the results presented here it seems that CHB patients do not express appropriate levels of the genes in the TLRs pathway which may lead to impaired immune responses against HBV infection which is seen in the patients.

Downregulation of CCR5 expression on the peripheral blood CD8+ T cells of southeastern Iranian patients with chronic hepatitis B infection

Studies indicated that CC receptor 5 (CCR5), as a receptor for CC ligand 3, CCL4, and CCL5, plays important roles in the recruitment of T cytotoxic lymphocytes to the liver of chronic HBV (CHB)-infected patients. The main purpose of this study was to investigate the expression levels of CCR5 on the CD8(+) T lymphocytes of CHB patients. This clinical study was performed on 63 CHB patients and 96 healthy controls. Flow cytometric analysis was performed to examine the expression of CCR5 on CD8(+) T cells of CHB patients. Real-time PCR was also used for HBV-DNA quantification. The results of our study demonstrated that CCR5 expressing T cytotoxic cells were decreased significantly in CHB patients in comparison to healthy control. Based on our results, it can be concluded that the percent of CCR5(+)/CD8(+) T cells in Iranian CHB patients is significantly decreased, hence their migration to the infected liver, and HBV eradication from the hepatocytes is disrupted.

High Serum Levels of TGF-β in Iranians With Chronic HBV Infection

BACKGROUND

The transforming growth factor-β (TGF-β) is an important cytokine with anti-inflammatory properties.

OBJECTIVES

The main purpose of this study was to compare the serum levels of TGF-β in a group of chronic HBV infected (CHB) patients as well as healthy individuals from South-East of Iran.

PATIENTS AND METHODS

Sixty patients with CHB as well as sixty healthy individuals were enrolled in the study. ELISA technique was applied to measure the serum levels of TGF-β in both groups.

RESULTS

Our results revealed that the serum levels of TGF-β were significantly increased in CHB patients in compare to healthy controls.

CONCLUSIONS

According to this result, it may be concluded that high serum levels of TGF-β may be a mechanism by which immune response against HBV is suppressed.

Acute-on-chronic liver failure in chronic hepatitis B

Acute-on-chronic liver failure (ACLF) in chronic hepatitis B (CHB) is most commonly caused by acute severe exacerbation of CHB. The pathophysiology of ACLF in CHB is still poorly understood. Despite the identification of important predisposing factors and prognostic markers, ACLF in CHB remains a disease associated with high mortality. The majority of studies using nucleoside analog therapy did not show any significant improvement in survival, although larger prospective studies are needed. Liver transplantation is the definitive treatment for ACLF in CHB. The challenge ahead would be prognosticating cases with favorable or unfavorable outcomes in order to streamline patients for early transplantation or for medical therapy.

Immunopathogenesis and prognostic immune markers of chronic hepatitis B virus infection

Host immune responses induced by hepatitis B virus (HBV) infection not only substantially drive disease progression, but also significantly influence efficacy of antiviral treatments in HBV-infected individuals. Therefore, it is important to fully understand the course of immune pathogenesis and to find efficient immunological markers that can predict the disease progression of chronic HBV infection. This review introduces the current progress in clinical immunology and analyzes the mechanisms of antiviral effects and liver injury, which are induced by both innate and adaptive immune responses. The recently identified immunological markers indicated to be closely correlated with disease progression and antiviral efficacy during HBV infection are also summarized. Careful monitoring of these immune markers may help physicians to make decisions on when to begin or withdraw antiviral drugs, or to formulate the prognosis of acute-on-chronic liver failure (ACLF) patients in the clinic. Finally, this review highlights some novel therapeutic strategies to modulate host immunity that have been proposed to sustain antiviral control of chronic HBV infection, as well as the challenges that we are presently facing in the field.

Host immunity influences disease progression and antiviral efficacy in humans infected with hepatitis B virus

Hepatitis B virus (HBV) infection can lead to several severe liver diseases, including hepatitis, cirrhosis and hepatocellular carcinoma, although the underlying mechanisms responsible for the clinical outcome have not been well characterized. In this review, we retrospectively examine the history of immunological responses to HBV infection and summarize the current understanding of innate and adaptive immunity in the context of HBV-associated liver disease. Recent data indicate that the interaction between HBV and the host immune response not only substantially drives disease progression, but also significantly influences antiviral efficacy in HBV-infected individuals. Advances in the field have provided insight into the immunopathology of HBV infection. Based on the characteristics of host immune responses in patients with HBV infection, a 'climbing slope hypothesis' is proposed to suggest that therapeutic strategies aimed at modulating the immune activity of the host may represent a complementary approach to antiviral drug treatment for the management of chronically HBV-infected patients.

Dynamic decrease in PD-1 expression correlates with HBV-specific memory CD8 T-cell development in acute self-limited hepatitis B patients

BACKGROUND/AIMS

Programmed death-1 (PD-1) upregulation can impair virus-specific CD8 T-cell responses during chronic viral infection. Whether and how PD-1 affects virus-specific memory CD8 T cells in humans with acute viral infection, however, remains largely undefined.

METHODS

The association between PD-1 expression and HBV-specific memory CD8 T-cell responses were longitudinally analyzed in eighteen patients with acute hepatitis B virus (HBV) infection, including ten patients with human leucocyte antigen (HLA)-A201 and eight with other HLA-A2 subtypes.

RESULTS

At clinical onset, PD-1 was significantly up-regulated and subsequently led to the functional suppression of HBV-specific effector CD8 T cells, as blocking PD-1/PD-L1 interactions in vitro enhanced their proliferation and IFN-gamma production. Following disease resolution, HBV-specific effector CD8 T cells developed into memory T cells. During this period, the dynamic PD-1 decrease was numerically correlated with the reduction of HBV-specific CD8 T-cell frequency, phenotypically with an acquisition of CCR7, CD45RA and CD127 expressions, and functionally with the increase in proliferation and IFN-gamma production of the memory T cells.

CONCLUSIONS

PD-1-mediated inhibitory signaling not only attenuates HBV-specific CD8 T-cell effector function during the acute phase of infection but also correlates with the development of HBV-specific memory CD8 T cells following disease resolution.

Activated plasmacytoid dendritic cells act synergistically with hepatitis B core antigen-pulsed monocyte-derived dendritic cells in the induction of hepatitis B virus-specific CD8 T-cell response

It is important to further improve the efficiency of hepatitis B core antigen-pulsed monocyte-derived dendritic cell (core-DC) vaccine in clinical immunotherapy for chronic hepatitis B virus (HBV) infection in humans. Our study shows that CpG-treated plasmacytoid dendritic cells (pDCs) can efficiently promote core-DC terminal maturation and increase interleukin-12 production. These CpG-activated pDCs can act synergistically in vitro with core-DCs in inducing autologous HBV-specific CD8 T-cell proliferation and interferon (IFN)-gamma production. This promotion was mainly dependent on pDC-derived IFN-alpha, because blockade of IFN-alpha nearly completely aborted the effects of pDCs on core-DCs. In addition, the supernatants derived from CpG-treated peripheral blood mononuclear cells can also effectively improve the aforementioned maturation and function of core-DCs. These findings will facilitate a better understanding of how the pDCs regulate myeloid dendritic cell-mediated immune responses, and highlight the notion that manipulating pDCs might have implications in DC vaccine therapy for patients with chronic hepatitis B.