Intrahost evolution of HBe antigen-negative hepatitis B virus genomes ascribed to the F genotype: a longitudinal 3 year retrospective study

The intrahost hepatitis B virus (HBV) genomic evolution process of an HBe antigen (HBeAg)-negative chronic HBV patient (designated RI) was studied. Two nearly full-length direct sequences obtained in 1995 (RI95) and 1998 (RI98) showed: (a) a mutation rate of 2.7x10(-3) nucleotides per site per year; (b) nucleotide changes mainly located at single coding regions (P=0.002); (c) mixed populations; and (d) a predominance of non-synonymous substitutions (P=0.0036). Population heterogeneity was assessed by cloning and sequencing of a fragment spanning nearly half the genome. Two-thirds of the analysed clones exhibited long nucleotide deletions. Pairwise genetic diversity revealed that diversity was higher for RI95 than for RI98 cloned sequences. In conclusion, a highly heterogeneous genomic population circulated within patient RI, which might support the persistence of HBV. Finally, the structure of the deletant genomes suggests that they might serve as intermediates for integration to the host-cell genome.

Hepatitis B virus infection and replication in primarily cultured human fetal hepatocytes

AIM: To investigate the infection and replication of hepatitis B virus (HBV) in primarily cultured human fetal hepatocytes (HFHs).

METHODS: The human fetal hepatocytes were cultured in serum-free medium, HBV-positive serum was added into the medium to study the susceptibility of hepatocytes to HBV infection. The supernatant was collected for ELISA assay of HBsAg and HBeAg, and quantitative fluorescence PCR for HBV-DNA assay daily. Albumin and HBcAg, CK8 and CK18 expressions were detected by immunohistochemistry in cultured hepatocytes. Content of lactate dehydrogenate (LDH) was measured to find out the integrity of the cell membrane.

RESULTS: A stable hepatocyte culture system was established. HBV could infect the hepatocytes and replicate, and HBcAg expression could be detected by immunohistochemistry in hepatocyte-like cells. HBV-DNA in the supernatant could be detected from d 2 to d 18 and HBsAg and HBeAg were positive on d 3-d 18 after HBV infection. HBV in medium increased from d 0 to d 6 and subsequently decreased as the cells were progressively loosing their hepatocyte phenotypes.

CONCLUSION: HBV could infect human fetal hepato-cytes and replicate. This in vitro model allowed a detailed study on early events associated with human HBV entry into cells and subsequent replication.

Anti-hepatitis B virus activity of wogonin in vitro and in vivo

The traditional Chinese medicine Scutellaria radix has been used for thousands of years, mainly for the treatment of inflammatory conditions including hepatitis. The major active constituent, wogonin (WG), isolated from S. radix has attracted increasing scientific attention in recent years due to its potent biological activities. However, pharmacologic studies have primarily been focused on wogonin's anti-inflammatory and anti-cancer activities. In this study, we have investigated wogonin's anti-hepatitis B virus (HBV) activity both in vitro and in vivo. In the human HBV-transfected liver cell line HepG2.2.15, wogonin effectively suppressed the secretion of the HBV antigens with an IC(50) of 4 microg/ml at day 9 for both HBsAg and HBeAg. Consistent with the HBV antigen reduction, wogonin also reduced HBV DNA level in a dose-dependent manner. Duck hepatitis B virus (DHBV) DNA polymerase was dramatically inhibited by wogonin with an IC(50) of 0.57 microg/ml. In DHBV-infected ducks wogonin dosed i.v. once a day for 10 days reduced plasma DHBV DNA level with an ED(50) of 5mg/kg. The in vivo anti-HBV effect of wogonin in ducks was confirmed by Southern blotting of DHBV DNA in the liver. Histopathological evaluation of the liver revealed significant improvement by wogonin. In addition, in human HBV-transgenic mice, wogonin dosed i.v. once a day for 10 days significantly reduced plasma HBsAg level. Immunohistological staining of the liver confirmed the HBsAg reduction by wogonin. In conclusion, our results demonstrate that wogonin possesses potent anti-HBV activity both in vitro and in vivo. Currently, wogonin is under early development as an anti-HBV drug candidate.

Cost effectiveness of entecavir versus lamivudine with adefovir salvage in HBeAg-positive chronic hepatitis B

OBJECTIVE

To evaluate the cost effectiveness of treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) with entecavir compared with lamivudine with adefovir salvage, based primarily on the results of a recent 2-year, randomised, multicentre, clinical trial (n = 709). Previous economic analyses have been limited by the lack of comparative clinical data for entecavir and lamivudine beyond 1-year duration and for salvage therapy.

METHODS

We conducted a cost-utility analysis using a Markov model from a US-payer perspective over a lifetime time horizon. The hypothetical cohort was 35-year-old patients with HBeAg-positive CHB. We evaluated 2 years of treatment with entecavir 0.5mg/day versus lamivudine 100mg/day, plus addition of adefovir 10mg/day for patients who developed virologic breakthrough due to resistance to either drug. In a scenario analysis, we considered adefovir plus lamivudine combination therapy for treatment-naive patients. Clinical and economic inputs ($US, year 2006 values) were derived from publicly available data, and probabilistic sensitivity analyses were conducted to evaluate uncertainty in the results.

RESULTS

The estimated 10-year cumulative incidence of cirrhosis for patients initiated on entecavir was 2.3% lower than for those on lamivudine (20.5% vs 22.8%). The discounted incremental cost per QALY gained was $US7600 in the base-case analysis, and the 95% central range from probabilistic sensitivity analysis was $US2500-$US19 100. Combination therapy for treatment-naive patients led to an increase in costs without improvement in patient outcomes compared with entecavir monotherapy.

CONCLUSIONS

Our analysis suggests entecavir improves health outcomes in a cost-effective manner compared with lamivudine with adefovir salvage or combination therapy, and highlights the importance of using evidence-based effectiveness estimates in economic studies of CHB therapies.

Two-year lamivudine treatment for hepatitis B e antigen-negative chronic hepatitis B: a double-blind, placebo-controlled trial

OBJECTIVE

We conducted a multicentre, double-blind, placebo-controlled, randomized study to investigate the efficacy of 2-year lamivudine treatment in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B.

METHODS

One-hundred-and-thirty-nine treatment-naive patients with HBeAg-negative chronic hepatitis B were randomized to receive either lamivudine (100 mg daily) or placebo in a 2:1 ratio for 24 months and were followed for an additional 6 months. The primary endpoint was complete response, defined as hepatitis B virus (HBV) DNA < 10,000 copies/ml and normalization of alanine aminotransferase (ALT) levels at month 24.

RESULTS

On intent-to-treat analysis at month 24, significantly more patients in the lamivudine group than in the placebo group had complete response (56% and 11%, respectively; P < 0.001) or negative HBV DNA (26% and 6%, respectively; P = 0.006). After adjustment of baseline HBV DNA and ALT, the odds ratio for complete response of the lamivudine group versus the placebo group was 10.8 (95% confidence interval: 3.8-30.2; P < 0.001). The median log HBV DNA reduction was 3.21 copies/ml for the lamivudine group compared with 0.47 copies/ml for the placebo group (P < 0.001). Genotypic resistance was detected in 23% and 31% of patients in the lamivudine group at months 12 and 24, respectively. Negative HBV DNA at month 6 was associated with high complete response (84%) and low drug resistance (1%) at month 24. At month 30, there was no difference between lamivudine and placebo groups in the rates of complete response (26% vs 19%, respectively; P = 0.38) or negative HBV DNA (10% vs 2%, respectively; P = 0.09).

CONCLUSIONS

Two-year lamivudine treatment is effective in HBeAg-negative chronic hepatitis B. However, the response is not sustained after treatment cessation.

Intracellular antibody fragment against hepatitis B virus X protein does not inhibit viral replication

Replication of the hepatitis B virus is suppressed by deficiency of the X protein. Although several molecules that block cellular targets of X protein reduce the production of hepatitis B virus progeny, the effect of a specific inhibitor of X protein on viral replication has not been investigated. To block X protein specifically, we adopted an intracellular expression approach using H7 single chain variable fragment (H7scFv), an antibody fragment against X protein. We previously demonstrated that cytoplasmic expression of H7scFv inhibits X protein-induced tumorigenicity and transactivation. In this study, intracellular H7scFv expression inhibits reporter gene transactivation but not viral replication determined by endogenous hepatitis B virus polymerase activity assay and real-time PCR. Our findings imply that intracellular expression of antibody fragment against X protein may not be an alternative therapeutic modality for inhibition of hepatitis B virus replication.

Inhibition of hepatitis B virus expression and replication by RNA interference in HepG2.2.15

AIM: To observe the inhibition of hepatitis B virus replication and expression by transfecting vector-based small interference RNA (siRNA) pGenesil-HBV X targeting HBV X gene region into HepG2.2.15 cells.

METHODS: pGenesil-HBV X was constructed and transfected into HepG2.2.15 cells via lipofection. HBV antigen secretion was determined 24, 48, and 72 h after transfection by time-resolved immunofluorometric assays (TRFIA). HBV replication was examined by fluorescence quantitative PCR, and the expression of cytoplasmic viral proteins was determined by immunohistochemistry.

RESULTS: The secretion of HBsAg and HBeAg into the supernatant was found to be inhibited by 28.5% and 32.2% (P < 0.01), and by 38.67% (P < 0.05) and 42.86% (P < 0.01) at 48 h and 72 h after pGenesil-HBV X transfection, respectively. Immunohistochemical staining for cytoplasmic HBsAg showed a similar decline in HepG2.2.15 cells 48 h after transfection. The number of HBV genomes within culture supernatants was also significantly decreased 48 h and 72 h post-transfection as quantified by fluorescence PCR (P < 0.05).

CONCLUSION: In HepG2.2.15 cells, HBV replication and expression is inhibited by vector-based siRNA pGenesil-HBV X targeting the HBV X coding region.

Cultivation of HepG2.2.15 on Cytodex-3: higher yield of hepatitis B virus and less subviral particles compared to conventional culture methods

BACKGROUND/AIMS

Several novel systems are available to study human hepatitis B virus (HBV) replication in cell culture demanding for efficient cell culture based systems for HBV production. The aim was to enhance HBV production of the HBV stably producing cell line HepG2.2.15 by cultivation on spherical micro substrate.

METHODS

HepG2.2.15 was cultivated on microcarrier substrate Cytodex-3. HBV specific transcripts, viral protein and genome secretion, cell proliferation and MAP kinase signaling were analyzed. Infectivity of HBV particles was analyzed using primary tupaia hepatocytes.

RESULTS

Compared to stationary flask cultures, HepG2.2.15 on Cytodex-3 secreted 18-fold more HBV genomes, more HBeAg per culture volume and less HBV surface antigen per extracellular viral genome equivalent. This was reflected by a significantly higher infectivity of supernatant derived from carrier grown HepG.2.2.15 cells tested by infection of primary tupaia hepatocytes. The amount of phosphorylated ERK-2 was significantly elevated in cells cultivated on microcarrier.

CONCLUSIONS

The cultivation of HepG2.2.15 on Cytodex-3 increased production of infectious HBV particles and decreased secretion of subviral particles compared to the stationary cell cultivation. Microcarrier cultivation activates MAP kinase signaling that is crucial for HBV replication.

[Inhibition of hepatitis B and duck hepatitis B virus replication by APOBEC3G]

OBJECTIVE

To investigate the effect of apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) mediated antiviral activity against hepatitis B virus (HBV) and duck hepatitis B virus (DHBV).

METHODS

Total RNA was extracted from peripheral blood mononuclear cells (PBMCs), RT-PCR product was cloned into the EcoR I/Hind III restriction sites of the CMV-driven expression vector fused with a hemagglutinin fusion epitope tag at its carboxyl terminal. Replication competent 1.3 fold over-length HBV was constructed with full-length HBV of ayw subtype. The mammalian hepatoma cell HepG2 was cotransfected with the replication competent 1.3 fold over-length HBV and various amounts of CMV-driven expression vector encoding APOBEC3G-HA. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA, HBV DNA. RNA from intracellular core particles was examined using Northern and Southern blot analyses. Chicken hepatoma cell LMH was cotransfected with head-to-tail dimer of an EcoR I monomer of DHBV and various amounts of CMV-driven expression vector encoding APOBEC3G-HA. DHBV DNA from intracellular core particles was examined using Southern blot analysis.

RESULTS

CMV-driven expression vector encoding APOBEC3G-HA and replication competent 1.3 fold over-length HBV were constructed. There was a dose dependent decrease in the levels of intracellular core-associated viral (HBV and DHBV) DNA and extracellular production of HBsAg and HBeAg. Levels of intracellular core-associated viral RNA were also decreased, but the expression of HBcAg remained almost unchanged.

CONCLUSION

APOBEC3G suppresses HBV and DHBV replication and also suppresses HBsAg and HBeAg expression.

Inhibition of hepatitis B virus production by Boehmeria nivea root extract in HepG2 2.2.15 cells

AIM: To explore the anti-hepatitis B virus (HBV) effects of Boehmeria nivea (B. nivea) root extract (BNE) by using the HepG2 2.2.15 cell model system.

METHODS: Hepatitis B surface antigen (HBsAg), hepatitis B virus e antigen (HBeAg), and HBV DNA were measured by using ELISA and real-time PCR, respectively. Viral DNA replication and RNA expression were determined by using Southern and Northern blot, respectively.

RESULTS: In HepG2 2.2.15 cells, HBeAg (60%, P < 0.01) and particle-associated HBV DNA (> 99%, P < 0.01) secretion into supernatant were significantly inhibited by BNE at a dose of 100 mg/L, whereas the HBsAg was not inhibited. With different doses of BNE, the reduced HBeAg was correlated with the inhibition of HBV DNA. The anti-HBV effect of BNE was not caused by its cytotoxicity to cells or inhibition of viral DNA replication and RNA expression.

CONCLUSION: BNE could effectively reduce the HBV production and its anti-HBV machinery might differ from the nucleoside analogues.

Human hepatitis B viral e antigen interacts with cellular interleukin-1 receptor accessory protein and triggers interleukin-1 response

Human hepatitis B virus (HBV) can cause acute and chronic hepatitis, cirrhosis, and hepatocellular carcinoma. HBV e antigen (HBeAg), a secreted protein and not required for viral replication, is thought to play an immunoregulatory role during viral infection. However, the functional involvement of HBeAg in host immune response has not been fully elucidated. We report in this study that HBeAg can bind to interleukin-1 receptor accessory protein (IL-1RAcP). Interleukin-1 (IL-1) plays an important role in inflammation and regulation of immune response, and membrane form of IL-1RAcP (mIL-1RAcP) is an essential component of trimeric IL-1/IL-1 receptor/mIL-1RAcP complex. We show that glutathione S-transferase- or polyhistidine-tagged recombinant HBeAg can interact with endogenous mIL-1RAcP in vitro. Purified (His)6-HBeAg added in the culture medium can interact with overexpressed FLAG-tagged mIL-1RAcP in vivo. Indirect immunofluorescence and confocal microscopy show that HBeAg colocalizes with mIL-1RAcP on the cell surface. Furthermore, HBeAg is able to induce the interaction of IL-1 receptor I (IL-1RI) with mIL-1RAcP and trigger the recruitment of adaptor protein myeloid differentiation factor 88 (MyD88) to the IL-1RI/mIL-1RAcP complex. Assembly and activation of IL-1RI/mIL-1RAcP signaling complex by HBeAg can activate downstream NF-kappaB pathway through IkappaB degradation, induce NF-kappaB-dependent luciferase expression, and induce the expression of IL-1-responsive genes. Silencing of IL-1RAcP by small interfering RNA dramatically abolishes HBeAg-mediated NF-kappaB activation. These results demonstrate that HBeAg can trigger host IL-1 response by binding to mIL-1RAcP. The interaction of HBeAg with mIL-1RAcP may play an important role in modulating host immune response in acute and chronic HBV infection.

Characteristics of patients with chronic hepatitis B in France: predominant frequency of HBe antigen negative cases

BACKGROUND/AIMS

An increasing prevalence of HBe antigen (HBeAg) negative chronic hepatitis B has been recently reported in many countries. The aim of this study was to analyze the frequency and the characteristics of HBeAg-negative as compared with HBeAg-positive chronic hepatitis B in France.

METHODS

Eight hundred and sixty-five patients with histologically proven chronic hepatitis B seen in 26 University centers were included. The proportion with HBeAg-negative chronic hepatitis B was 72% and higher in patients born in Africa, Middle East, Eastern, and Southern Europe than in those of French or Asian origin. HBeAg-negative patients were significantly older (p<0.001) and had lower ALT levels and HBV DNA serum levels (p<0.01) than HBeAg-positive patients. An unknown source of infection was more prevalent in HBeAg-negative patients (p<0.05). Fibrosis score (p<0.05) and proportion of cirrhosis (p<0.01) were significantly higher in HBeAg-negative patients. Age older than 50 years, male gender and viral load lower than 5 logs10 copies/mL were independently associated with cirrhosis.

RESULTS

HBeAg-negative chronic hepatitis B is predominant in France. This observation is important for an optimized clinical management and future therapeutic trials in chronic hepatitis B.

Functional analysis of complex hepatitis B virus variants associated with development of liver cirrhosis

BACKGROUND & AIMS

Development of cirrhosis in renal transplant recipients with chronic hepatitis B is associated with the accumulation of complex hepatitis B virus (HBV) variants carrying deletions in the C gene and/or preS region and deletions/insertions in the core promoter. Here, we characterized for the first time the phenotype of these complex HBV variants.

METHODS

Representative full-length genomes of the HBV variants that were isolated and cloned from serum and liver of an immunosuppressed renal transplant recipient before and during end-stage liver disease were transfected into the human hepatoma cell line HuH7 and functionally analyzed.

RESULTS

The variant genomes showed considerably reduced levels of precore and surface messenger RNA (mRNA) and of the major spliced pregenomic RNA, an increased level of pregenomic RNA, and a partial or complete defect in hepatitis B e antigen, core, and surface protein expression/secretion. Very low amounts of variant core protein with internal deletion were detectable. Reduced hepatitis B surface antigen secretion of some variants correlated with aberrant localization of surface proteins in endoplasmic reticulum. Despite the defects in viral protein expression, enhanced replication and enrichment in competition to wild-type HBV were observed. Enhanced reverse transcription and possibly increased levels of pregenomic RNA seem to be responsible for this effect.

CONCLUSIONS

Development of cirrhosis is associated with accumulation of complex variants, which exhibit a drastically altered phenotype combining enhanced replication with defects in protein expression. This phenotype appears to be based on the major mutations in the core promoter and C gene but is considerably influenced by additional mutations throughout the genome.

Inhibition of hepatitis B virus replication by APOBEC3G in vitro and in vivo

AIM: To investigate the effect of APOBEC3G mediated antiviral activity against hepatitis B virus (HBV) in cell cultures and replication competent HBV vector-based mouse model.

METHODS: The mammalian hepatoma cells Huh7 and HepG2 were cotransfected with various amounts of CMV-driven expression vector encoding APOBEC3G and replication competent 1.3 fold over-length HBV. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA. The expression of HBcAg in transfected cells was detected by western blot. HBV DNA and RNA from intracellular core particles were examined by Northern and Southern blot analyses. To assess activity of the APOBEC3G in vivo, an HBV vector-based model was used in which APOBEC3G and the HBV vector were co-delivered via high-volume tail vein injection. Levels of HBsAg and HBV DNA in the sera of mice as well as HBV core-associated RNA in the liver of mice were determined by ELISA and quantitative PCR analysis respectively.

RESULTS: There was a dose dependent decrease in the levels of intracellular core-associated HBV DNA and extracellular production of HBsAg and HBeAg. The levels of intracellular core-associated viral RNA also decreased, but the expression of HBcAg in transfected cells showed almost no change. Consistent with in vitro results, levels of HBsAg in the sera of mice were dramatically decreased. More than 1.5 log10 decrease in levels of serum HBV DNA and liver HBV RNA were observed in the APOBEC3G-treated groups compared with the control groups.

CONCLUSION: These findings indicate that APOBEC3G could suppress HBV replication and antigen expression both in vivo and in vitro, promising an advance in treatment of HBV infection.

[Screening and identification of genes trans-regulated by a novel HbeAg interacting protein AK026018 with microarray assay]

BACKGROUND

To investigate the biological functions of a novel hepatitis B virus e antigen (HbeAg) interacting protein AK026018, and to use cDNA microarray technique to screen genes regulated by the protein.

METHODS

The AK026018 coding DNA fragment was amplified by reverse transcription polymerase chain reaction (RT-PCR) technique from HepG2 cell. The expressive vector of pcDNA3.1-AK was constructed by routine molecular biological methods. The HepG2 cells were transfected with pcDNA3.1 and pcDNA3.1-AK, respectively by using lipofectamine. The total RNA was isolated and reverse transcribed. The cDNA of each sample was subjected to microarray screening with 8,464 cDNA probes and analyzed by bioinformatics.

RESULTS

The expressive vector was constructed and confirmed by DNA sequencing analysis and restriction enzyme digestion. High quality mRNA and cDNA of transfected HepG2 cells had been prepared and successful microarray screening conducted. From the scanning results, there were 122 differential expression genes, of which 36 genes were down-regulated, and 16 genes were up-regulated.

CONCLUSION

Microarray technique was successfully used to screen the genes trans-regulated by AK026018. The expression of AK026018 protein affects the expression spectrum of HepG2 cells.

[Establishment of immortalized B lymphoblast cell line from patients with chronic hepatitis B]

AIM

To establish immortalized B lymphoblast cell line (BLCL) from patients with chronic hepatitis B (CHB) in vitro.

METHODS

The peripheral blood mononuclear cells (PBMC) were isolated from the patients with CHB by routine method and incubated with EB virus (EBV) in the presence of CpG DNA motifs and cyclosporin A (CysA) for about 28 days. Morphological characteristic of the established immortalized BLCL was observed by microscope and the expression of CD19 and CD23 on cellular surface was determined by flow cytometry.

RESULTS

BLCL was successfully established and could be cultured and propagated for a long time in vitro.

CONCLUSION

EBV-immortalized BLCL provides a resource of target cells for further research on the cellular immunity of patients with CHB.

The degrees of hepatocyte cytoplasmic expression of hepatitis B core antigen correlate with histologic activity of liver disease in the young patients with chronic hepatitis B infection

Subcellular localizaton of HBcAg have been found to be related to the activity of liver disease and HBV replication. The aim of this study was to determine whether the degree of expression of HBcAg in the hepatocyte nucleus and cytoplasm reflects the level of viral replication and histological activity in chronic HBV infection. A total of 102 patients with biopsy proven chronic hepatitis B were included. There was a highly significant correlation between the levels of HBV DNA in serum and the degree of expression of HBcAg in the nucleus for HBeAg-positive(p=0.000) and negative patients(p=0.04). There was a highly significant, correlation between the degrees of expression of HBcAg in hepatocyte cytoplasm and histologic activities (p<0.01) for HBeAg-positive patients. The degrees of expression of HBcAg in the hepatocyte cytoplasm correlated positively with the lobular activities (p<0.01), but not correlated with the portal activity and fibrosis for HBeAg-negative patients. In conclusion, in the young patients with chronic B viral hepatitis, the degree of expression of HBcAg in the hepatocyte nucleus may affect viral load, and the degree of expression of HBcAg in the hepatocyte cytoplasm may affect histologic activities of liver disease.

Point mutations upstream of hepatitis B virus core gene affect DNA replication at the step of core protein expression

The pregenomic RNA directs replication of the hepatitis B virus (HBV) genome by serving both as the messenger for core protein and polymerase and as the genome precursor following its packaging into the core particle. RNA packaging is mediated by a stem-loop structure present at its 5' end designated the epsilon signal, which includes the core gene initiator AUG. The precore RNA has a slightly extended 5' end to cover the entire precore region and, consequently, directs the translation of a precore/core protein, which is secreted as e antigen (HBeAg) following removal of precore-derived signal peptide and the carboxyl terminus. A naturally occurring G1862T mutation upstream of the core AUG affects the bulge of the epsilon signal and generates a "forbidden" residue at the -3 position of the signal peptide cleavage site. Transfection of this and other mutants into human hepatoma cells failed to prove their inhibition of HBeAg secretion but rather revealed great impairment of genome replication. This replication defect was associated with reduced expression of core protein and could be overcome by a G1899A covariation, or by nonsense or frameshift mutation in the precore region. All these mutations antagonized the G1862T mutation on core protein expression. Cotransfection of the G1862T mutant with a replication-deficient HBV genome that provides core protein in trans also restored genome replication. Consistent with our findings in cell culture, HBV genotype A found in African/Asian patients has T1862 and is associated with much lower viremia titers than the European subgroup of genotype A.

Clinical significance of hepatitis B virus (HBV) genotypes and precore and core promoter mutations affecting HBV e antigen expression in Taiwan

To assess the prevalence and clinical significance of hepatitis B virus (HBV) genotypes and precore and core promoter mutations in Taiwan, a cohort of 200 Taiwanese chronic hepatitis B patients was analyzed. The HBV genotypes and sequences of the precore and the core promoter regions were determined in 66 asymptomatic carriers and 134 patients who had liver biopsy-verified chronic hepatitis and liver cirrhosis. The HBV e-antigen (HBeAg)-negative patients had a higher frequency of mutations at core promoter nucleotides 1753 and 1773 and precore nucleotides 1846, 1896, and 1899 than HBeAg-positive patients. Among the 200 patients, the frequencies of genotype C, T1762 and A1764, C1753, T1766 and A1768, and A1896 mutations increased and the frequencies of T or G1752, T1773, G1799, and C1858 mutations decreased with advancing liver diseases. These factors were different between those with HBeAg-positive status and those with HBeAg-negative status. Based on multiple logistic regression analysis, the risk factors of liver cirrhosis for 200 patients were the presence of T1762 and A1764 mutations (odds ratio [OR] = 11.11; 95% confidence interval [CI] = 3.91 to 31.25; P < 0.001), age > or =35 years (OR = 3.42; 95% CI = 1.33 to 8.77; P = 0.011), and genotype C (OR = 2.87; 95% CI = 1.21 to 6.81; P = 0.017). Further categorical analysis found that 62.1% of patients with genotype C, T1762 and A1764 mutations and age > or =35 years had liver cirrhosis. None of the 55 patients infected with the genotype B, A1762 and G1764 wild type and age <35 years showed liver cirrhosis. In conclusion, our data suggest that pathogenic differences between HBeAg-positive and -negative patients may exist. In Taiwan, HBV genotype C and the T1762 and A1764 mutations may play a role in HBV-related liver cirrhosis, and these could serve as molecular markers for prediction of the clinical outcomes of chronic HBV patients.

[Effects of ciclosporin and tacrolimus on replication of hepatitis B virus in vitro: a comparative study]

OBJECTIVE

To investigate the effects of ciclosporin (CsA) and tacrolimus (FK506) on replication of hepatitis B virus (HBV) in vitro.

METHODS

HBV genome permanently transfected human liver cancer cells of the line HepG2.2.15 were cultured. CsA and FK506 at different concentrations were added into the culture fluid so as to identify the nontoxic concentrations by MTT method. Then the HepG2.2.15 cells were treated by CsA and FK506 at different nontoxic concentrations respectively for 4 days. ELISA was used to detect the HB surface antigen (HBsAg) and HB e antigen (HBeAg) in the supernatant. The relative replication level of HBV DNA was detected by slot blot analysis.

RESULTS

MTT method confirmed that the nontoxic concentrations of CsA and FK506 were 0-40.0 microg/ml and 0-400 ng/ml respectively. After the treatment of CsA at the concentration of 1.3, 2.5, and 5.0 microg/ml, in comparison to the control group, the suppression rates of HBsAg expression in the HepG2.2.15 cells were 16.5% +/- 9.4%, 21.5% +/- 8.9%, and 33.1% +/- 5.3% respectively (all P < 0.05); the suppression rates of HBeAg expression in the HepG2.2.15 cells were 7.8% +/- 2.2%, 11.0% +/- 2.3%, and 20.8% +/- 1.5% respectively (all P < 0.05); and the HBV DNA replication levels were 56 +/- 16, 42 +/- 11, and 40 +/- 10 respectively (P > 0.05, P < 0.05, and P > 0.05). However, FK506 at different nontoxic concentrations showed no significant inhibitory effect on the levels of HBsAg, HBeAg, and HBV DNA.

CONCLUSION

CsA dose-dependently inhibits the HBV replication in vitro, and FK506 does not exercise similar effects.

[Inhibition of HBsAg and HBeAg secretion by RNA interference of the polymerase gene sequence of hepatitis B virus: an experimental study]

OBJECTIVE

To investigate the effects of small interfering RNA (siRNA) targeting the polymerase (P) gene sequence of hepatitis B virus (HBV) on the replication and antigen secretion of HBV.

METHODS

From the 29 base sequences of the HBV in the HepG2.2.15 cells that accord with the demands of siRNA designing five sequences targeting the P gene of HBV were selected and cloned into the siRNA expressing vector pGE-1. Then the plasmid pGE-HBVP was transfected into the cultured HepG2.2.15 cells. Chemiluminescent immunoassay was used to determine the levels of HBsAg and HBeAg in the supernatant of culture medium 24, 48, 72, and 96 hours after the transfection and the expression of HBsAg in the 2.2.15 cells 24 hours after the transfection so as to observe the inhibitory effects. Untransfected cells and cells transfected with blank pGE-1 vector were used as controls.

RESULTS

Five vectors expressing the siRNAs targeting the HBV P region, pGE-HBVP1-pGE-HBV5 were successfully constructed. The efficiency of transfection of the vectors into the 2.2.15 cells were 30% to 40%. 24, 48, 72, and 96 hours after the transfection of pGE-HBVP2, the strongest inhibitor among the five, the inhibitory rates of HBsAg secretion in the supernatant were 28.88%, 32.28%, 29.10%, and 18.42% respectively; and the inhibitory rates of HBeAg secretion were 38.33%, 27.50%, 33.41%, and 12.60% respectively. In view of the transfection efficiency of 30%-40%, the actual inhibitory rate of HBV antigen secretion might reach 80% and over. 24 hours after the transfection the expression rate of HBsAg in the 2.2.15 cells transfected with pGE-HBVP2 was 50%, significantly lower than that in the cells transfected with the blank vector pGE-1 (82%).

CONCLUSION

siRNAs targeting the HBV P gene effectively prevent the HBV gene expression and replication and may play an important role in the clinical anti-viral treatment.

Reduced secretion of virions and hepatitis B virus (HBV) surface antigen of a naturally occurring HBV variant correlates with the accumulation of the small S envelope protein in the endoplasmic reticulum and Golgi apparatus

We identified two novel naturally occurring mutations (W74L and L77R) in the small S envelope protein of hepatitis B virus (HBV). Mutation L77R alone resulted in >10-fold-reduced secretion of virions. In addition, the 2.8-fold reduction of the extracellular HBV surface antigen (HBsAg) of mutant L77R from transfected Huh7 cells appeared to be correlated with a 1.7-fold reduction of intracellular HBsAg, as measured by enzyme-linked immunosorbent assay (ELISA). Surprisingly, opposite to the ELISA results, Western blot analysis revealed a near-10-fold-increased level of the intracellular mutant small S envelope protein. The discrepancy between ELISA and Western blot data was due to significant accumulation of the mutant L77R HBsAg in the intracellular pellet fraction. In contrast to HBsAg, the secretion of HBeAg was normal in L77R-transfected cells. The wild-type HBsAg was usually more diffuse and evenly distributed in the cytoplasm, often outside the perinuclear endoplasmic reticulum (ER) and Golgi apparatus, as observed by immunofluorescence assay. In contrast, the L77R mutant HBsAg tends to be highly restricted within the ER and Golgi, often accumulated in the Golgi compartments distal from the nucleus. The almost exclusive retention in the ER-Golgi of L77R HBsAg was similar to what was observed when the large envelope protein was overexpressed. These multiple aberrant phenotypes of mutant L77R can be corrected by a second naturally occurring S envelope mutation, W74L. Despite the accumulation of L77R HBsAg in ER-Golgi of transfected Huh7 cells, we detected no increase in Grp78 mRNA and proteins, which are common markers for ER stress response.

Antiviral activities of extracts and selected pure constituents of Ocimum basilicum

1. Ocimum basilicum (OB), also known as sweet basil, is a well known medicinal herb in traditional Chinese medicine preparations. In the present study, extracts and purified components of OB were used to identify possible antiviral activities against DNA viruses (herpes viruses (HSV), adenoviruses (ADV) and hepatitis B virus) and RNA viruses (coxsackievirus B1 (CVB1) and enterovirus 71 (EV71)). 2. The results show that crude aqueous and ethanolic extracts of OB and selected purified components, namely apigenin, linalool and ursolic acid, exhibit a broad spectrum of antiviral activity. Of these compounds, ursolic acid showed the strongest activity against HSV-1 (EC50 = 6.6 mg/L; selectivity index (SI) = 15.2), ADV-8 (EC50 = 4.2 mg/L; SI = 23.8), CVB1 (EC50 = 0.4 mg/L; SI = 251.3) and EV71 (EC50 = 0.5 mg/L; SI = 201), whereas apigenin showed the highest activity against HSV-2 (EC50 = 9.7 mg/L; SI = 6.2), ADV-3 (EC50 = 11.1 mg/L; SI = 5.4), hepatitis B surface antigen (EC50 = 7.1 mg/L; SI = 2.3) and hepatitis B e antigen (EC50 = 12.8 mg/L; SI = 1.3) and linalool showed strongest activity against AVD-II (EC50 = 16.9 mg/L; SI = 10.5). 3. No activity was noted for carvone, cineole, beta-caryophyllene, farnesol, fenchone, geraniol, beta-myrcene and alpha-thujone. 4. The action of ursolic acid against CVB1 and EV71 was found to occur during the infection process and the replication phase. 5. With SI values greater than 200, the potential use of ursolic acid for treating infection with CVB1 and EV71 merits further investigation.

[Experimental study on the inhibitory effect of Carboxymethyl Pachymaram on hepatitis B virus expression from transfected cells]

OBJECTIVE

To observe the anti-HBV activity of Carboxymethyl Pachymaram (CMP) on the culturing of 2.2.15 cell line.

METHODS

Concentrations of 20.0 g/L, 12.0 g/L, 6.0 g/L, 3.0 g/L, 1.5 g/L of CMP were used to evaluate its toxicity to the cell line and the inhibition rates of the secretion of HBsAg and HBeAg in the cultured 2.2.15 cell line.

RESULTS

Experiments showed that the mean half toxicity concentration of CMP for 2.2.15 cell line was 13.6 g/L and concentration for 50% inhibition of the secretion of HBsAg and HBeAg were 4.45 g/L, 5.61 g/L and TI were 3.06 and 2.42. CMP showed stronger effect on anti-HBV than aciclovir.

CONCLUSION

CMP has good inhibitory effect on the secretion of HBsAg and HBeAg on cultured cell line 2.2.15.