Role of anti-HBs in functional cure of HBeAg+ chronic hepatitis B patients infected with HBV genotype A.

Background & Aims: HBsAg-specific antibody responses are difficult to detect during chronic hepatitis B infection (CHB) and are often overlooked. The aim of this study was to examine whether anti-HBs may be involved in functional cure (FC) by profiling anti-HBs responses in patients with CHB using a panel of specific assays.

Methods: Longitudinal serum samples were obtained from 25 patients with CHB who were infected with HBV genotype A and were undergoing nucleos(t)ide analogue (NA) treatment: 14 achieved FC while 11 remained infected (non-FC).

Analysis of Hepatitis B Virus Haplotype Diversity Detects Striking Sequence Conservation Across Genotypes and Chronic Disease Phase.

Background And Aims: We conducted haplotype analysis of complete hepatitis B virus (HBV) genomes following deep sequencing from 368 patients across multiple phases of chronic hepatitis B (CHB) infection from four major genotypes (A-D), analyzing 4,110 haplotypes to identify viral variants associated with treatment outcome and disease progression.

Approach And Results: Between 18.2% and 41.

Molecular characterization of hepatitis B virus (HBV) in African children living in Australia identifies genotypes and variants associated with poor clinical outcome.

Migration from sub-Saharan Africa is contributing to the rising incidence of chronic hepatitis B (CHB) infection and its complications in Australia. African CHB is associated with unique genotypes, such as E and A1, which are associated with reduced vaccine efficacy and early-onset hepatocellular carcinoma, respectively, although the prevalence of these genotypes outside Africa is poorly described. Treatment-naïve children of African origin with CHB were recruited at the Royal Children's Hospital Melbourne.

In vitro studies identify a low replication phenotype for hepatitis B virus genotype H generally associated with occult HBV and less severe liver disease.

Hepatitis B virus (HBV) exists as 9 major genotypes and multiple subtypes, many of which exhibit differences in pathogenicity and treatment response. Genotype H identified in Central America is associated with low incidence of liver disease and HCC, but higher incidence of occult HBV (low level HBV DNA positivity, HBsAg negative). The replication phenotype of genotype H associated with less severe forms of liver disease is unknown.

Novel HBsAg mutations correlate with hepatocellular carcinoma, hamper HBsAg secretion and promote cell proliferation in vitro.

Background: An impaired HBsAg-secretion can increase HBV oncogenic-properties. Here, we investigate genetic-determinants in HBsAg correlated with HBV-induced hepatocellular carcinoma (HCC), and their impact on HBsAg-secretion and cell-proliferation.

Methods: This study included 128 chronically HBV-infected patients: 23 with HCC (73.

Stop codons in the hepatitis B surface proteins are enriched during antiviral therapy and are associated with host cell apoptosis.

Premature stop codons in the hepatitis B virus (HBV) surface protein can be associated with nucleos(t)ide analogue resistance due to overlap of the HBV surface and polymerase genes. The aim of this study was to determine the effect of the replication of three common surface stop codon variants on the hepatocyte. Cell lines were transfected with infectious HBV clones encoding surface stop codons rtM204I/sW196*, rtA181T/sW172*, rtV191I/sW182*, and a panel of substitutions in the surface proteins.

In Vitro Studies Show that Sequence Variability Contributes to Marked Variation in Hepatitis B Virus Replication, Protein Expression, and Function Observed across Genotypes.

Unlabelled: The hepatitis B virus (HBV) exists as 9 major genotypes (A to I), one minor strain (designated J) and multiple subtypes. Marked differences in HBV natural history, disease progression and treatment response are exhibited by many of these genotypes and subtypes. For example, HBV genotype C is associated with later hepatitis B e antigen (HBeAg) seroconversion and high rates of liver cancer compared to other HBV genotypes, whereas genotype A2 is rarely associated with HBeAg-negative disease or liver cancer.

Single-Molecule Sequencing Reveals Complex Genome Variation of Hepatitis B Virus during 15 Years of Chronic Infection following Liver Transplantation.

Unlabelled: Chronic hepatitis B (CHB) is prevalent worldwide. The infectious agent, hepatitis B virus (HBV), replicates via an RNA intermediate and is error prone, leading to the rapid generation of closely related but not identical viral variants, including those that can escape host immune responses and antiviral treatments. The complexity of CHB can be further enhanced by the presence of HBV variants with large deletions in the genome generated via splicing (spHBV variants).

Toll-IL1 receptor-mediated innate immune responses vary across HBV genotype and predict treatment response to pegylated-IFN in HBeAg-positive CHB patients.

Patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) have suppressed TLR2 expression, function and cytokine production. The aim of this study was to explore the importance of hepatitis B virus (HBV) genotype in innate immune responses and investigate whether Toll-like receptor (TLR) expression/function has potential roles as predictive biomarkers of successful therapy with pegylated interferon (Peg-IFN) therapy of HBeAg seroconversion in HBeAg-positive patients. We showed that as early as 4 weeks after initiation of Peg-IFN, future HBeAg seroconverters had significantly elevated levels of TLR2 expression on monocytes.

Cellular inhibitor of apoptosis proteins prevent clearance of hepatitis B virus.

Hepatitis B virus (HBV) infection can result in a spectrum of outcomes from immune-mediated control to disease progression, cirrhosis, and liver cancer. The host molecular pathways that influence and contribute to these outcomes need to be defined. Using an immunocompetent mouse model of chronic HBV infection, we identified some of the host cellular and molecular factors that impact on infection outcomes.

Downregulation of interleukin-18-mediated cell signaling and interferon gamma expression by the hepatitis B virus e antigen.

Unlabelled: The mechanisms by which hepatitis B virus (HBV) establishes and maintains chronic hepatitis B infection (CHB) are poorly defined. Innate immune responses play an important role in reducing HBV replication and pathogenesis. HBV has developed numerous mechanisms to escape these responses, including the production of the secreted hepatitis B e antigen (HBeAg), which has been shown to regulate antiviral toll-like receptor (TLR) and interleukin-1 (IL-1) signaling.

Hepatitis B virus genotype C encoding resistance mutations that emerge during adefovir dipivoxil therapy: in vitro replication phenotype.

Introduction: Hepatitis B virus (HBV) can be classified into ten genotypes (A-J), with genotypes B and C being the most common in Asia. Recent data suggest that the HBV genotype can influence disease progression, and genotype C has been associated with more aggressive liver disease than that of other genotypes. Although there is a preventative vaccine, chronic infection remains a public health problem with oral nucleos(t)ide analog therapy being the most common treatment.

In vitro replication phenotype of a novel (-1G) hepatitis B virus variant associated with HIV co-infection.

The -1G mutant HBV is more prevalent in individuals co-infected with HIV/HBV than in individuals infected with HBV alone and in some cases is the dominant virus in circulation. This mutant is created by the deletion of a dGMP (-1G) from the guanine rich homopolymer sequence located at nts 2,085-2,090 (numbering from EcoRI site as position 1) in the HBV core gene. This deletion causes a frameshift generating a premature stop codon at (64) Asn in the HBV core gene (codon 93 in the precore gene), that truncates the precore protein, precursor of the secreted hepatitis B "e" antigen (HBeAg), and the core protein which forms the viral nucleocapsid.

The hepatitis B e antigen suppresses IL-1β-mediated NF-κB activation in hepatocytes.

Previous clinical studies have demonstrated an association between the hepatitis B e antigen and Toll-like receptor (TLR) expression and signalling. Therefore, the aim of this study was to develop an in vitro assay to measure the effect of hepatitis B virus proteins, including the precore protein, on signalling mediated by members of the Toll-like/interleukin 1 (TIR) superfamily, by measuring NF-κB promoter activity. The basal level of NF-κB reporter activity was measured in three hepatocyte cell lines (Huh7, HepG2 and PH5CH8) and one kidney cell line (HEK293) using a luciferase assay.

Targeting the hepatitis B virus precore antigen with a novel IgNAR single variable domain intrabody.

The Hepatitis B virus precore protein is processed in the endoplasmic reticulum (ER) into secreted hepatitis B e antigen (HBeAg), which acts as an immune tolerogen to establish chronic infection. Downregulation of secreted HBeAg should improve clinical outcome, as patients who effectively respond to current treatments (IFN-α) have significantly lower serum HBeAg levels. Here, we describe a novel reagent, a single variable domain (V(NAR)) of the shark immunoglobulin new antigen receptor (IgNAR) antibodies.

Stimulation of the interleukin-1 receptor and Toll-like receptor 2 inhibits hepatitis B virus replication in hepatoma cell lines in vitro.

Background: Toll-like receptors (TLRs) are a key component of the innate immune system and TLR2 has been shown to be involved in the immunopathogenesis of hepatitis B virus (HBV) infection in vivo. We investigated the role of TLR2 stimulation of virus-infected hepatocyte cell lines as a potential antiviral mechanism in vitro.

Methods: The hepatoblastoma cell line HepG2 was transduced with recombinant HBV baculoviruses and the hepatoma cell line Huh-7 was transiently transfected with complimentary DNA clones of HBV.

The phenylpropenamide derivative AT-130 blocks HBV replication at the level of viral RNA packaging.

Nucleos(t)ide analogue antiviral therapy for chronic hepatitis B has proven to be effective in the short term but the frequent development of resistance limits its clinical utility. Agents targeting other stages of viral replication are needed in order to develop improved combination therapies. The phenylpropenamide derivatives AT-61 and AT-130 have been shown to inhibit HBV replication in vitro, but the mechanism of action of these compounds remains undefined.

Identification of a novel hepatitis B virus precore/core deletion mutant in HIV/hepatitis B virus co-infected individuals.

Objectives: Although HAART has resulted in improved health outcomes for most HIV-infected individuals, liver failure has emerged as a major cause of morbidity and mortality in people co-infected with hepatitis B virus (HBV). In HBV mono-infected individuals, core deletion mutants are associated with more aggressive liver disease. As HIV accelerates HBV liver disease progression, we hypothesized that HIV-HBV co-infected individuals have increased frequency of core mutations including deletions.

SeqHepB: a sequence analysis program and relational database system for chronic hepatitis B.

SeqHepB is a combination of a HBV genome sequence analysis program and a relational database that houses data collected from multiple data sources. Registered users can access the sequence analysis component of SeqHepB online for rapid and detailed interrogation of HBV genomic sequences. Its main function is to determine the HBV genotype, identify key mutations associated with antiviral resistance, and identify clinically important HBV mutants.

Cellular response to conditional expression of the hepatitis B virus precore and core proteins in cultured hepatoma (Huh-7) cells.

Background: The expression of the hepatitis Be antigen (HBeAg) is one of several strategies used by hepatitis B virus (HBV) to ensure persistence. The HBeAg may function as a toleragen in utero and has been shown to regulate the host's immune response.

Aim: The aim of this study was to examine the effect of the HBV precore and core protein on cellular gene expression in the hepatoma cell line Huh-7.

Resistance to adefovir dipivoxil therapy associated with the selection of a novel mutation in the HBV polymerase.

Background & Aims: Adefovir dipivoxil effectively inhibits both hepatitis B virus (HBV) replication and disease activity in patients with chronic hepatitis B. Resistance to treatment was not observed in 2 recent large placebo-controlled 48-week studies with this drug. The aim of this study was to characterize adefovir resistance in a patient who developed clinical and virologic evidence of breakthrough during a 96-week course of treatment.

Effect of the G1896A precore mutation on drug sensitivity and replication yield of lamivudine-resistant HBV in vitro.

Hepatitis B e antigen (HBeAg) negative chronic hepatitis B (CHB) is frequently caused by a mutation (G1896A) in the hepatitis B virus (HBV) precore (PC) reading frame that creates a stop codon, causing premature termination of the PC protein. During lamivudine treatment, drug resistance develops at a similar rate in HBeAg positive and HBeAg negative CHB. Lamivudine-resistant HBV mutants have been shown to replicate inefficiently in vitro in the absence of PC mutations, but it is unknown whether the presence of PC mutations affects replication efficiency or antiviral sensitivity.