HBV vaccination and HBV infection induces HBV-specific natural killer cell memory.

OBJECTIVE: Vaccination against hepatitis B virus (HBV) confers protection from subsequent infection through immunological memory that is traditionally considered the domain of the adaptive immune system. This view has been challenged following the identification of antigen-specific memory natural killer cells (mNKs) in mice and non-human primates. While the presence of mNKs has been suggested in humans based on the expansion of NK cells following pathogen exposure, evidence regarding antigen-specificity is lacking. Here, we demonstrate the existence of HBV-specific mNKs in humans after vaccination and in chronic HBV infection. DESIGN: NK cell responses were evaluated by flow cytometry and ELISA following challenge with HBV antigens in HBV vaccinated, non-vaccinated and chronic HBV-infected individuals. RESULTS: NK cells from vaccinated subjects demonstrated higher cytotoxic and proliferative responses against autologous hepatitis B surface antigen (HBsAg)-pulsed monocyte-derived dendritic cells (moDCs) compared with unvaccinated subjects. Moreover, NK cell lysis of HBsAg-pulsed moDCs was significantly higher than that of hepatitis B core antigen (HBcAg)-pulsed moDCs (non-vaccine antigen) or tumour necrosis factor α-activated moDCs in a NKG2D-dependent manner. The mNKs response was mediated by CD56dim NK cells coexpressing CD57, CD69 and KLRG1. Further, mNKs from chronic hepatitis B patients exhibited greater degranulation against HBcAg-pulsed moDCs compared with unvaccinated or vaccinated patients. Notably, mNK activity was negatively correlated with HBV DNA levels. CONCLUSIONS: Our data support the presence of a mature mNKs following HBV antigen exposure either through vaccination or infection. Harnessing these antigen specific, functionally active mNKs provides an opportunity to develop novel treatments targeting HBV in chronic infection.

Sorted B cell transcriptomes point towards actively regulated B cell responses during ongoing chronic hepatitis B infections.

The natural course of chronic hepatitis B virus (HBV) infections follows distinct clinical disease phases, characterized by fluctuating levels of serum HBV DNA and ALT. The immune cells and their features that govern these clinical disease transitions remain unknown. In the current study, we performed RNA sequencing on purified B cells from blood (n = 42) and liver (n = 10) of healthy controls and chronic HBV patients. We found distinct gene expression profiles between healthy controls and chronic HBV patients, as evidenced by 190 differentially expressed genes (DEG), but also between the clinical phenotypes of a chronic HBV infection (17-110 DEG between each phase). Numerous immune pathways, including the B cell receptor pathway were upregulated in liver B cells when compared to peripheral B cells. Further investigation of the detected DEG suggested an activation of B cells during HBeAg seroconversion and an active regulation of B cell signalling in the liver.

Use of Expression Profiles of HBV-DNA Integrated Into Genomes of Hepatocellular Carcinoma Cells to Select T Cells for Immunotherapy.

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is often associated with hepatitis B virus (HBV) infection. Cells of most HBV-related HCCs contain HBV-DNA fragments that do not encode entire HBV antigens. We investigated whether these integrated HBV-DNA fragments encode epitopes that are recognized by T cells and whether their presence in HCCs can be used to select HBV-specific T-cell receptors (TCRs) for immunotherapy. METHODS: HCC cells negative for HBV antigens, based on immunohistochemistry, were analyzed for the presence of HBV messenger RNAs (mRNAs) by real-time polymerase chain reaction, sequencing, and Nanostring approaches. We tested the ability of HBV mRNA-positive HCC cells to generate epitopes that are recognized by T cells using HBV-specific T cells and TCR-like antibodies. We then analyzed HBV gene expression profiles of primary HCCs and metastases from 2 patients with HCC recurrence after liver transplantation. Using the HBV-transcript profiles, we selected, from a library of TCRs previously characterized from patients with self-limited HBV infection, the TCR specific for the HBV epitope encoded by the detected HBV mRNA. Autologous T cells were engineered to express the selected TCRs, through electroporation of mRNA into cells, and these TCR T cells were adoptively transferred to the patients in increasing numbers (1 × 104-10 × 106 TCR+ T cells/kg) weekly for 112 days or 1 year. We monitored patients' liver function, serum levels of cytokines, and standard blood parameters. Antitumor efficacy was assessed based on serum levels of alpha fetoprotein and computed tomography of metastases. RESULTS: HCC cells that did not express whole HBV antigens contained short HBV mRNAs, which encode epitopes that are recognized by and activate HBV-specific T cells. Autologous T cells engineered to express TCRs specific for epitopes expressed from HBV-DNA in patients' metastases were given to 2 patients without notable adverse events. The cells did not affect liver function over a 1-year period. In 1 patient, 5 of 6 pulmonary metastases decreased in volume during the 1-year period of T-cell administration. CONCLUSIONS: HCC cells contain short segments of integrated HBV-DNA that encodes epitopes that are recognized by and activate T cells. HBV transcriptomes of these cells could be used to engineer T cells for personalized immunotherapy. This approach might be used to treat a wider population of patients with HBV-associated HCC.

A novel hepatitis B virus species discovered in capuchin monkeys sheds new light on the evolution of primate hepadnaviruses.

BACKGROUND & AIMS: All known hepatitis B virus (HBV) genotypes occur in humans and hominoid Old World non-human primates (NHPs). The divergent woolly monkey HBV (WMHBV) forms another orthohepadnavirus species. The evolutionary origins of HBV are unclear. METHODS: We analysed sera from 124 Brazilian monkeys collected during 2012-2016 for hepadnaviruses using molecular and serological tools, and conducted evolutionary analyses. RESULTS: We identified a novel orthohepadnavirus species in capuchin monkeys (capuchin monkey hepatitis B virus [CMHBV]). We found CMHBV-specific antibodies in five animals and high CMHBV concentrations in one animal. Non-inflammatory, probably chronic infection was consistent with an intact preCore domain, low genetic variability, core deletions in deep sequencing, and no elevated liver enzymes. Cross-reactivity of antisera against surface antigens suggested antigenic relatedness of HBV, CMHBV, and WMHBV. Infection-determining CMHBV surface peptides bound to the human HBV receptor (human sodium taurocholate co-transporting polypeptide), but preferentially interacted with the capuchin monkey receptor homologue. CMHBV and WMHBV pseudotypes infected human hepatoma cells via the human sodium taurocholate co-transporting polypeptide, and were poorly neutralised by HBV vaccine-derived antibodies, suggesting that cross-species infections may be possible. Ancestral state reconstructions and sequence distance comparisons associated HBV with humans, whereas primate hepadnaviruses as a whole were projected to NHP ancestors. Co-phylogenetic analyses yielded evidence for co-speciation of hepadnaviruses and New World NHP. Bayesian hypothesis testing yielded strong support for an association of the HBV stem lineage with hominoid ancestors. Neither CMHBV nor WMHBV was likely the ancestor of the divergent human HBV genotypes F/H found in American natives. CONCLUSIONS: Our data suggest ancestral co-speciation of hepadnaviruses and NHP, and an Old World origin of the divergent HBV genotypes F/H. The identification of a novel primate hepadnavirus offers new perspectives for urgently needed animal models of chronic hepatitis B. LAY SUMMARY: The origins of HBV are unclear. The new orthohepadnavirus species from Brazilian capuchin monkeys resembled HBV in elicited infection patterns and could infect human liver cells using the same receptor as HBV. Evolutionary analyses suggested that primate HBV-related viruses might have emerged in African ancestors of New World monkeys millions of years ago. HBV was associated with hominoid primates, including humans and apes, suggesting evolutionary origins of HBV before the formation of modern humans. HBV genotypes found in American natives were divergent from those found in American monkeys, and likely introduced along prehistoric human migration. Our results elucidate the evolutionary origins and dispersal of primate HBV, identify a new orthohepadnavirus reservoir, and enable new perspectives for animal models of hepatitis B.

Clearing Persistent Extracellular Antigen of Hepatitis B Virus: An Immunomodulatory Strategy To Reverse Tolerance for an Effective Therapeutic Vaccination.

Development of therapeutic vaccines/strategies to control chronic hepatitis B virus (HBV) infection has been challenging because of HBV-induced tolerance. In this study, we explored strategies for breaking tolerance and restoring the immune response to the HBV surface Ag in tolerant mice. We demonstrated that immune tolerance status is attributed to the level and duration of circulating HBsAg in HBV carrier models. Removal of circulating HBsAg by a monoclonal anti-HBsAg Ab in tolerant mice could gradually reduce tolerance and reestablish B cell and CD4(+) T cell responses to subsequent Engerix-B vaccination, producing protective IgG. Furthermore, HBsAg-specific CD8(+) T cells induced by the addition of a TLR agonist resulted in clearance of HBV in both serum and liver. Thus, generation of protective immunity can be achieved by clearing extracellular viral Ag with neutralizing Abs followed by vaccination.

Higher disappearance rate of anti-HBs in Taiwanese freshers neonatally vaccinated with recombinant yeast hepatitis B vaccine.

BACKGROUND & AIM: The aim of this study was to compare the long-term efficacy of infant recombinant yeast hepatitis B vaccine (Recombinant group) and infant plasma-derived one (Plasma group) in Taiwanese freshers. METHODS: Recruited were a total of 38 377 freshmen who underwent university entrance health examinations from 2003 to 2015. Subjects were assigned into two groups-plasma type and recombinant type, according to the national neonatal hepatitis B immunization program. The seroprevalences of hepatitis B surface antigen, antibody against hepatitis B surface antigen, and antibody against hepatitis B core antigen in each group and gender were calculated. Multivariate logistic regression analysis was performed to compare the efficacy of two groups. RESULTS: The HBsAg-positive rates in the plasma group and recombinant group were 1.5% and 0.3% respectively. The anti-HBs positive rates were 43.6% and 30.9%. The hepatitis B viral natural infection rates were 3.6% and 1.3%. Taking those who were born in July 1986-April 1992 as baseline group after adjustment for gender and age at hepatitis B markers checkup time, the efficacy of recombinant group in decreasing HBsAg positive rate, and decreasing hepatitis B virus natural infection rate was 71.0% (95% C.I.: 59.0-79.0%, P<.001) and 65.0% (95% C.I. 58.0-71.0%, P<.001) respectively. On the contrary, the seroprevalence of anti-HBs positive rate in recombinant group was 39.0% (95% C.I.: 36.0-42.0%, P<.001) lower than that of plasma group. (P<.001). CONCLUSION: Higher disappearance rate of anti-HBs was noted in recombinant group than in plasma group when the subjects reached their youth and young adulthood in Taiwan.

[Hepatitis B Virus Infection: Current Management and Prevention].

Hepatitis B virus (HBV) is transmitted mainly via percutaneous or permucosal exposure to HBV- containing body fluids. Because HB vaccination is effective and safe, it is recommended for all children, ado- lescents, and all unvaccinated adults at risk of HBV infection (individuals with occupational risk, immunosup- pressed individuals, and sexually active individuals). In Japan, universal HB vaccination will be introduced for all infants in October 2016. In Japan, the prevalence of HBV genotype A, which is frequently found in North America, northwestern Europe, India, and Africa, has been increasing as a sexually transmitted infection. HBV reactivation under anticancer chemotherapy and immunosuppressive therapy is well-known as a seri- ous complication in HBV-resolved patients. Monthly monitoring of HBV-DNA is recommended for prevent- ing HBV reactivation-related hepatitis among HBV-resolved patients with non-Hodgkin B-cell lymphoma under steroid plus rituximab chemotherapy. Recently, a highly sensitive chemiluminescent enzyme immunoassay (CLEIA) for HBsAg detection by Lumipulse HBsAg-HQ was reported as the latest clinical application. Although the sensitivity of this assay (≥5 mIU/mL) is 10-fold higher than the conventional assay, it is still lower than that of the HBV-DNA assay. The useful HBsAg-HQ will be applied for detecting occult HBV infection and HBV reactivation. The aim of treatment for chronic HBV infection is to reduce the risk of complications, including cirrhosis and hepatocellular carcinoma (HCC). Pegylated interferon alfa and nucleoside/nucleotide analogues (NAs) are the current treatments for chronic HBV infection. NAs have improved the outcomes of patients with cirrhosis and HCC, and decreased the incidence of acute liver failure. [Review].

Identification of hepatitis B virus-specific CTL epitopes presented by HLA-A*33:03 in peripheral blood mononuclear cells from patients and transgenic mice.

Cytotoxic T lymphocyte (CTL) epitopes in the HBV protein of hepatitis B virus (HBV) may play a key role in viral control and liver damage. The aim of this study was to identify and study the function of HLA-A(∗)33:03-restricted CTL epitopes in HBV protein of the HBV genotypes B and C, which are epidemic in China. Sixteen HBV peptides were predicated by computational analysis, and synthesized peptides were examined for their affinity to HLA-A(∗)33:03 using a stable cell line. After being analyzed by enzyme-linked immunospot and cytolytic activity assays, as well as the tetramers staining method using peripheral blood mononuclear cells isolated from HBV-infected patients, five peptides (Hbs245-253, HBs335-343, HBc119-127, HBc104-112, and HBp391-399) were chosen to further confirm their HLA_A(∗)33:03 restriction in transgenic mice.

Decline in intrahepatic cccDNA and increase in immune cell reactivity after 12 weeks of antiviral treatment were associated with HBeAg loss.

Viral load reduction facilitates recovery of antiviral T-cell responses. Dynamic alterations in intrahepatic viraemia clearance and immune cell reactivity during the early phase of nucleoside analogue (NA) therapy and the impact of these changes on HBeAg seroconversion are unknown. Fifteen HBeAg-positive chronic hepatitis B (CHB) patients were treated with adefovir dipivoxil. T-cell reactivity to HBV core and surface antigens were tested using ELISPOT assay from baseline to week 48 post-treatment (at 4-week intervals). Before and at week 12 of treatment, paired liver biopsies were analysed for intrahepatic HBV-DNA and cccDNA via real-time fluorescent PCR. In situ detection of CD4(+) , CD8(+) T cells and NK cells was analysed by immunohistochemistry. With viral load reduction, HBV-specific IFN-γ-producing CD4(+) T cells in patients with HBeAg loss were greatly enhanced and reached the highest level at week 12, with further increase observed between week 36 and week 48. After 12 weeks of treatment, total intrahepatic HBV-DNA and cccDNA had significantly decreased; however, there was no difference in the viral loads or extent of reduction between patients with and without HBeAg loss. Paralleling reduction in viral load, intrahepatic CD8(+) T lymphocytes increased in patients with HBeAg loss compared with baseline values. Only one patient without HBeAg loss exhibited similar results. Increased immune cells were observed in certain patients along with reduced hepatic viral loads during the second phase of HBV-DNA decline, which could promote the recovery of antiviral immunity and facilitate HBeAg loss.

Phosphorylation of human La protein at Ser 366 by casein kinase II contributes to hepatitis B virus replication and expression in vitro.

Human La protein (hLa) is a multifunctional RNA-binding protein involved in the regulation of hepatitis B virus (HBV) expression. Casein kinase II (CK2), a protein kinase, is known to activate hLa by phosphorylating Ser(366). Tetrabromobenzimidazole (TBBz) has been shown to be a specific inhibitor of CK2 activity, which suggests that TBBz may be useful for reducing HBV gene expression. The aim of our study was to determine whether inhibition of CK2 by TBBz and decreased phosphorylation of hLa Ser(366) (pLa) would reduce HBV gene expression. pLa and total La expression levels were evaluated by immunohistochemistry in human liver tissues with or without HBV infection. HepG2.2.15 cells (an HBV-expressing cell line) were treated with TBBz, and cell viability and pLa levels were evaluated. Knockdown of hLa and CK2 levels by specific siRNA and mutant hLa Ala(366) were utilized to establish the roles of pLa and CK2 in HBV gene expression. HBV DNA replication and HBsAg and HBeAg levels were analysed in HepG2.2.15 cell supernatants by standard methods. pLa was significantly overexpressed in HBV-infected human liver samples. TBBz decreased the phosphorylation of hLa, which coincided with decreased HBV expression. Mutant hLa Ala(366) had reduced viral expression compared with hLa Ser(366) treatment in hLa siRNA knockdown cells. Knockdown of CK2 also decreased the HBV parameters. hLa plays a key role in the regulation of HBV gene expression in a CK2-dependent mechanism via phosphorylation of hLa at Ser(366).

Atypical serological profiles in hepatitis B virus infection.

During hepatitis B virus (HBV) infection, at least four antigen-antibody systems are observed: HBsAg and anti-HBs; preS antigen and anti-preS antibody; HBcAg and anti-HBc; and HBeAg and anti-HBe. Through the examination of these antigen-antibody systems, hepatitis B infection is diagnosed and the course of the disorder may be observed. Although the serologic findings that allow both the diagnosis of HBV infection as well as assessing of its clinical course are already well established, the dynamics of viral proteins expression and of the antibodies production may vary during the infection natural course. This causes the HBV infection to be occasionally associated with the presence of uncommon serological profiles, which could lead to doubts in the interpretation of results or suspicion of a serological result being incorrect. This paper is dedicated to the discussion of some of these profiles and their significance.

Evaluation of a programme for prevention of vertical transmission of hepatitis B in a rural block in southern India.

BACKGROUND & OBJECTIVES: This study was undertaken to evaluate a community based programme of antenatal screening for hepatitis B surface antigen (HBsAg) and selective immunization of children commencing at birth, at a secondary care hospital in south India. The primary objective was to assess immunization coverage among children born to HBsAg positive women; secondary objectives were to study the prevalence of HBsAg among antenatal women, prevalence of HBsAg among immunized children (to estimate vaccine efficacy), seroconversion rate and relationship of maternal hepatitis B e antigen (HBeAg) to hepatitis infection. METHODS: The prevalence of hepatitis B antigen among antenatal women and immunization coverage achieved with hepatitis B vaccine in a rural block in Vellore, Tamil Nadu were assessed through examination of records. Children born between May 2002 and December 2007 to hepatitis B positive women were followed up for a serological evaluation, based on which vaccine efficacy and the effect of maternal hepatitis B e antigen (HBeAg) on breakthrough infection was estimated. RESULTS: The prevalence of hepatitis B surface antigen among antenatal women was 1.58 % (95% CI: 1.35-1.81%). Vaccine coverage for three doses as per a recommended schedule (including a birth dose) was 70 per cent, while 82.4 per cent eventually received three doses (including a birth dose). Estimated vaccine efficacy was 68 per cent and seroconversion 92.4 per cent in children aged 6-24 months. Maternal HBeAg was significantly associated with either anti-HBc or HBsAg in immunized children, RR=5.89 (95% CI: 1.21-28.52%). INTERPRETATION & CONCLUSIONS: The prevalence of hepatitis B among antenatal women in this region was low and a programme of selective immunization was found to be feasible, achieving a high coverage for three doses of the vaccine including a birth dose.

Recombinant Semliki Forest virus vectors encoding hepatitis B virus small surface and pre-S1 antigens induce broadly reactive neutralizing antibodies.

Most hepatitis B virus (HBV) vaccines consist of viral small surface (S) protein subtype adw2 expressed in yeast cells. In spite of good efficacy, HBV-genotype and subtype differences, escape mutants and insufficient Th1 activation remain potential problems. To address these problems, we generated recombinant Semliki Forest virus (rSFV) vectors encoding S protein, subtype adw2 or ayw2, or a fragment of the large surface protein, amino acids 1-48 of the pre-S1 domain, fused to S (pre-S1.1-48/S). The antigen loop in S protein and the selected pre-S1 sequences are known targets of neutralizing antibodies. BALB/c mice were immunized intravenously with 10(7) rSFV particles and 10(8) rSFV particles 3 weeks later. Antibodies induced by rSFV encoding S proteins reacted preferentially with subtype determinants of yeast-derived S antigen but equally well with patient-derived S antigen. Immunization with rSFV encoding pre-S1.1-48/S resulted in formation of pre-S1- and S-specific immunoglobulin G (IgG), while immunization with the isogenic mutant without S start codon induced pre-S1 antibodies only. Neutralizing antibodies were determined by mixing with plasma-derived HBV/ayw2 and subsequent inoculation of susceptible primary hepatocyte cultures from Tupaia belangeri. S/adw2 antisera neutralized HBV/ayw2 as effectively as antisera raised with S/ayw2. The pre-S1 antibodies also completely neutralized HBV infectivity. The IgG1/IgG2a ratios ranged from 0.28 to 0.88 in the four immunized groups and were lowest for the pre-S1.1-48/S vector, indicating the strongest Th1 response. This vector type may induce subtype-independent and S-escape-resistant neutralizing antibodies against HBV.

Association between occult hepatitis B infection and the risk of hepatocellular carcinoma: a meta-analysis.

BACKGROUND: The association between occult hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC) remains controversial. AIMS: We conducted a meta-analysis of prospective studies and retrospective studies to examine whether occult HBV infection increases the risk of HCC. METHODS: Two independent reviewers searched databases for eligible studies published in English or Chinese dated from 1966 to 6 April 2010. The odds ratios or the relative risks (RRs) of each study were considered respectively. RESULTS: We identified 16 eligible studies. A significantly increased risk of HCC was found in subjects with occult HBV infection in comparison with non-infected controls in both retrospective [OR(unadjusted) =6.08, 95% confidence interval (CI)=3.45-10.72] and prospective studies (RR(adjusted) =2.86, 95% CI=1.59-4.13), and occult HBV increased the risk for HCC in both hepatitis C virus (HCV)-infected populations (summary RR=2.83, 95% CI=1.56-4.10) and in non-infected populations (OR(unadjusted) =10.65, 95% CI=5.94-19.08). A higher prevalence of occult HBV was observed in individuals who were positive for anti-HBs and anti-HBc (OR(unadjusted) =1.81, 95% CI=1.06, 3.09). CONCLUSION: Our findings suggest that occult HBV infection was associated with an increased risk of HCC. Occult HBV may serve as a cofactor in the development of HCV-related HCC, and it may also play a direct role in promoting Non-B and Non-C HCC growth. Suggestive evidence indicates that individuals with a concomitant presence of anti-HBs and anti-HBc had an increased risk of occult HBV infection. However, further studies are needed to clarify these observations.

Differential N-glycosylation of a monoclonal antibody expressed in tobacco leaves with and without endoplasmic reticulum retention signal apparently induces similar in vivo stability in mice.

Plant cells are able to perform most of the post-translational modifications that are required by recombinant proteins to achieve adequate bioactivity and pharmacokinetics. However, regarding N-glycosylation the processing of plant N-glycans in the Golgi apparatus displays major differences when compared with that of mammalian cells. These differences in N-glycosylation are expected to influence serum clearance rate of plant-derived monoclonal antibodies. The monoclonal antibody against the hepatitis B virus surface antigen expressed in Nicotiana tabacum leaves without KDEL endoplasmic reticulum (ER) retention signal (CB.Hep1(-)KDEL) and with a KDEL (Lys-Asp-Glu-Leu) fused to both IgG light and heavy chains (CB.Hep1(+)KDEL) were tested for in vivo stability in mice. Full characterization of N-glycosylation and aggregate formation in each monoclonal antibody batch was determined. The mouse counterpart (CB.Hep1) was used as control. Both (CB.Hep1(-)KDEL) and (CB.Hep1(+)KDEL) showed a faster initial clearance rate (first 24 h) compared with the analogous murine antibody while the terminal phase was similar in the three antibodies. Despite the differences between CB.Hep1(+)KDEL and CB.Hep1(-)KDEL N-glycans, the in vivo elimination in mice was indistinguishable from each other and higher than the murine monoclonal antibody. Molecular modelling confirmed that N-glycans linked to plantibodies were oriented away from the interdomain region, increasing the accessibility of the potential glycan epitopes by glycoprotein receptors that might be responsible for the difference in stability of these molecules.

Analysis of carriers of hepatitis B virus from a tertiary referral hospital: does the viral load change during the natural course of infection?

This study was designed to determine the prevalence, forms of transmission, mutational profile and viral load at baseline of hepatitis B virus (HBV) carriers in Delhi. HBV surface antigen (HBsAg)-positive patients were enrolled and evaluated clinically for liver function, serological markers for hepatitis B and HBV DNA quantitation. Tests were carried out again 1 year later and the results were compared. Liver biopsy was carried out on all carriers with active viral replication. HBV DNA-positive samples were subjected to polymerase chain reaction single-stranded conformation polymorphism (PCR-SSCP) to screen mutations in the Precore, core, and the X-gene prior to sequencing analysis. Among the 100 patients examined, HBeAg was detected in 23% and 40% were HBV DNA-positive. Of the 40 HBV DNA-positive cases, 8 had precore/core mutations, [G1896A (10%), T2066A (12.5%), T2050C (10%), and G1888A (7.5%)]. No X gene mutants were detected. Reduction in viral load was higher in HBeAg-positive patients, as compared to HBeAg-negative patients, over 1 year. At follow-up, 2/8 HBV mutants corresponded with altered liver function and morphological changes suggestive of chronic hepatitis. One patient was re-designated as DNA-negative on follow-up and had wild-type virus infection with a relatively low viral load. The predominant route for HBV transmission was determined to be parenteral. Twenty percent of the HBV carriers were infected with precore and core mutant HBV. Although the clinical and biochemical profiles of these HBV carriers remained largely stable on follow-up, there was evidence of spontaneous reduction in the mean viral load over the 1-year study period.

[The influence of HBV and its antigens on the expressions of JAK-STAT signal transduction pathway molecules and antiviral proteins of IFN alpha].

OBJECTIVE: To investigate the possible influence of HBV and its antigens on the expressions of JAK-STAT signal transduction pathway molecules and the antiviral proteins of IFN alpha. METHODS: The HepG2 cells were transfected with pSM2, pHBS2-S and pHBc-EGFP plasmids which express HBV whole particles or S-antigen, Pre-S antigen and core antigens. The infectious supernatant from HepG2.2.15 cells and the pured HBV proteins which contained the S, Pre-S antigens were used to treat the HepG2 cells. Northern blot and RT-PCR were applied to analyse the expressions of the antiviral proteins MxA, 2' -5' OAS, 9-27 and the JAK-STAT signal transduction pathway molecules STAT1 in HepG2 cells responded to the IFN alpha treatment. RESULTS: The HepG2 cells transfected with pSM2, pHBS2-S and pHBc-EGFP plasmids could express whole HBV particles and HBsAg, Pre-S antigen and HBcAg. The quantitation of expressed HBV particles and antigens increased significantly during the course of transfection. Northern blot hybridization analysis indicated that the HepG2 cells expressed IFN alpha antiviral proteins MxA, 2' -5' OAS and 9-27. When transfected with pHBV-dimer, pHBS2-S, pHBc-EGFP plasmids, the IFN/A antiviral proteins MxA, 2' -5' OAS and 9-27 in transfected cells were reduced greatly as compared to the un-transfected HepG2 cells, and the expressed antiviral proteins decreased sharply with the development of transfection time. Furthermore, the expression of IFN alpha JAK-STAT signal transduction pathway molecule STAT1 was also inhibited with the expression of HBV particles and HBV antigens in transfected HepG2 cells. CONCLUSIONS: The HBV and its antigens influence the expressions of IFN alpha JAK-STAT signal transduction pathway molecules and antiviral proteins in the hepatocellular models in vitro. It is indicated that HBV might possess the activity to antagonise or counteract the IFN alpha antiviral action.

The Functions of Hepatitis B Virus Encoding Proteins: Viral Persistence and Liver Pathogenesis.

About 250 million people worldwide are chronically infected with Hepatitis B virus (HBV), contributing to a large burden on public health. Despite the existence of vaccines and antiviral drugs to prevent infection and suppress viral replication respectively, chronic hepatitis B (CHB) cure remains a remote treatment goal. The viral persistence caused by HBV is account for the chronic infection which increases the risk for developing liver cirrhosis and hepatocellular carcinoma (HCC). HBV virion utilizes various strategies to escape surveillance of host immune system therefore enhancing its replication, while the precise mechanisms involved remain elusive. Accumulating evidence suggests that the proteins encoded by HBV (hepatitis B surface antigen, hepatitis B core antigen, hepatitis B envelope antigen, HBx and polymerase) play an important role in viral persistence and liver pathogenesis. This review summarizes the major findings in functions of HBV encoding proteins, illustrating how these proteins affect hepatocytes and the immune system, which may open new venues for CHB therapies.