• BMB Reports
• /
• v.37 no.2
• /
• pp.167-176
• /
• 2004

Although efficient antiviral lamivudine is used for HBV-infected patients, a prolonged treatment with nucleoside analogs often results in lamivudine-resistant variants. In this study, we evaluated the fidelity of the lamivudine-resistant variants. The FLAG-tagged wild-type (FPolE) and Met550 variants (FPolE/M550A, M550V, and M550I) of HBV DNA polymerases were expressed in insect cells then purified. Like many other reverse transcriptases, no $3'{\rightarrow}5'$ exonuclease activity was detected in the HBV DNA polymerase. Since there is no proofreading activity, then the use of the site-specific nucleotide misincorporation method is beneficial. From the $f_{ins}$ value analysis, it is evident that M550I and M550V exhibit higher fidelity values than the wild-type HBV DNA polymerase, while M550A exhibits similar fidelity values. It is therefore suggested that lamivudine resistance comes from the stringency to dNTP binding and the discrimination of dCTP and lamivudine in M550V and M550I.

• Biomolecules & Therapeutics
• /
• v.7 no.2
• /
• pp.133-137
• /
• 1999

This study was undertaken to test for anti-Hepatitis B virus (HBV) activity of the aqueous extracts prepared from Eugenia caryophyllate, Ephedra sinica, Cinnamomum cassia. Aqueous extracts were assayed for the inhibition of HBV replication by measurement of HBV DNA and surface antigen (HBsAg) levels in the extracellular medium of HePG2 2.2.15 cells. All extracts decreased the levels of extracellular HBV virion DNA at concentrations ranging from 128 to 256 $\mu$g/ml and inhibited the production of HBsAg dose-dependently. Our findings suggest that these three hebal medicinal plants may have potential to develop as specific anti-HBV drugs in the future.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.10
• /
• pp.4199-4202
• /
• 2015

Background: Hepatitis B virus infection is one of the major world health problems. Epigallocatechin-3 gallate is the major component of the polyphenolic fraction of green tea and it has an anti-viral, anti-mutagenic, anti-tumorigenic, anti-angiogenic, anti-proliferative, and/or pro-apoptotic effects on mammalian cells. In this study, our aim was to investigate the inhibition of HBV replication by epigallocatechin-3 gallate in the Hep3B2.1-7 hepatocellular carcinoma cell line. Materials and Methods: HBV-replicating Hep3B2.1-7 cells were used to investigate the preventive effects of epigallocatechin-3 gallate on HBV DNA replication. The expression levels of HBsAg and HBeAg were determined using ELISA. Quantitative real-time-PCR was applied for the determination of the expression level of HBV DNA. Results: Cytotoxicity of epigallocathechin-3-gallate was not observed in the hepatic carcinoma cell line when the dose was lower than $100{\mu}M$. The ELISA method demonstrated that epigallocatechin-3 gallate have strong effects on HBsAg and HBeAg levels. Also it was detected by real-time PCR that epigallocatechin-3 gallate could prevent HBV DNA replication. Conclusions: The obtained data pointed out that although the exact mechanism of HBV DNA replication and related diseases remains unclear, epigallocatechin-3 gallate has a potential as an effective anti-HBV agent with low toxicity.

• Archives of Pharmacal Research
• /
• v.29 no.11
• /
• pp.1042-1048
• /
• 2006

Plasmid DNA vaccines encoding the hepatitis B virus (HBV) surface and hepatitis C virus (HCV) envelope antigens, respectively, were constructed, and attempt were made to find the possibility of a divalent vaccine against HBV and HCV. The expression of each plasmid in Cos-1 cells was confirmed using immunocytochemistry. To measure the induced immune response by these plasmids in vivo, female BALB/c mice were immunized intramuscularly with $100\;{\mu}g$ of either both or just one of the plasmids. Anti-HBV and HCV-specific antibodies and related cytokines were evaluated to investigate the generation of both humoral and cellular immune responses. As a result, specific anti-HBV and anti-HCV serum antibodies from mice immunized with these plasmids were observed using immunoblot. The levels of IL-2 and RANTES showing a $Th_{1}$ immune response were significantly increased, but there was no change in the level of IL-4 ($Th_{1}$ immune response) in any of the immunized groups. Compared with each plasmid DNA vaccine, the combined vaccine elicited similar immune responses in both humoral and cell-mediated immunities. These results suggest that the combined DNA vaccine can induce not only comparable immunity experimentally without antigenic interference, but also humoral and $Th_{1}$ dominant cellular immune responses. Therefore, they could serve as candidates for a simultaneous bivalent vaccine against HBV and HCV infections.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.22
• /
• pp.9635-9641
• /
• 2014

Background: This retrospective study was aimed to investigate the efficacy of prophylactic agents in hepatocellular carcinoma (HCC) patients receiving TACE and compare the difference between lamivudine and entecavir. Materials and Methods: A consecutive series of 203 HBV-related HCC patients receiving TACE were analyzed including 91 patients given prophylactic agents. Virologic events, defined as an increase in serum HBV DNA level to more than 1 log10 IU/ml higher than the nadir level, hepatitis flares due to HBV reactivation and progression free survival (PFS) were the main endpoints. Results: Some 48 (69.6%) reached virologic response. Prophylaxis significantly reduced virologic events (8.8% vs 58.0%, p=0.000) and hepatitis flares (1.1% vs 13.4%, p=0.001). Patients presenting undetectable HBV DNA levels displayed a significantly improved PFS as compared to those who never achieved undetectable HBV DNA. Prophylaxis and e-antigen positivity were the only significant variables associated with virologic events. In addition, prophylaxis was the only independent protective factor for hepatitis flares. Liver cirrhosis, more cycles of TACE, HBV DNA negativity, a lower Cancer of the Liver Italian Program score, non-metastasis and no hepatitis flares were protective factors for PFS. Prophylactic lamivudine demonstrated similar efficacy as entecavir. Conclusions: Prophylactic agents are efficacious for prevention of HBV reactivation in HCC patients receiving TACE. Achievement of undetectable HBV DNA levels displayed a significant capability in improving PFS. Moreover, persistent tumor residual lesions, positive HBV DNA and hepatitis B flares might be causes of tumor progression in these patients.

• IMMUNE NETWORK
• /
• v.5 no.1
• /
• pp.1-10
• /
• 2005

Background: Chronic infection with hepatitis B virus (HBV) affects about 350 million people worldwide, which have a high risk of development of cirrhosis and hepatocellular carcinoma. Treatment of chronic HBV infection relies on IFN-${\alpha}$ or lamivudine. However, interferon-${\alpha}$ is effective in only about 30% of patients. Also, the occurrence of escape mutations limits the usage of lamivudine. Therefore, the development and evaluation of new compounds or approaches are urgent. Methods: We comparatively evaluated DNA and adenoviral vaccines expressing HBV antigens, either alone or in combined regimens, for their ability to elicit Th1-type immune responses in Balb / c mice which are believed to be suited to resolve HBV infection. The vaccines were tested with or without a genetically engineered IL-12 (mIL-12 N220L) which was shown to enhance sustained Th1-type immune responses in HCV E2 DNA vaccine. Results: Considering the Th1-type cytokine secretion and the IgG2a titers, the strongest Th1-type immune response was elicited by the DNA prime-adenovirus boost regimen in the presence of mIL-12 N220L. In addition, the codelivery of mIL-12 N220L modulated differentially the immune responses by different vaccination regimens. Conclusion: Our results suggest that the DNA prime-adenovirus boost regimen in the presence of mIL-12 N220L may be the best candidate for HBV vaccine therapy of the regimens tested in this study and will be worthwhile being evaluated in chronic HBV patients.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.1
• /
• pp.16-24
• /
• 2021

Hepatitis B virus (HBV) genome P-encoded protein HBV DNA polymerase (Pol) has long been known as a reverse transcriptase during HBV replication. In this study, we investigated the impact of HBV Pol on host cellular processes, mainly apoptosis, and the underlying mechanisms. We showed a marked reduction in apoptotic rates in the HBV Pol-expressed HepG2 cells compared to controls. Moreover, a series of assays, i.e., yeast two-hybrid, GST pull-down, co-immunoprecipitation, and confocal laser scanning microscopy, identified the host factor eEF1A2 to be associated with HBV Pol. Furthermore, knockdown of eEF1A2 gene by siRNA abrogated the HBV Pol-mediated anti-apoptotic effect with apoptosis induced by endoplasmatic reticulum (ER) stress-inducer thapsigargin (TG), thus suggesting that the host factor eEF1A2 is essential for HBV Pol's anti-apoptosis properties. Our findings have revealed a novel role for HBV Pol in its modulation of apoptosis through integrating with eEF1A2.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.13 no.1
• /
• pp.44-50
• /
• 2010

Purpose: To estimate the viral suppressive effect of entecavir monotherapy in Korean children and adolescents with lamivudine-resistant chronic hepatitis B (CHB). Methods: One milligram of entecavir was administered once daily to 6 patients (4 boys; mean age, 17.5 years; range, 15.10~24.6 years) with lamivudine-resistant CHB for a mean duration of therapy of 13.4 months (range, 1~21.1 months). The therapeutic results were compared with 11 patients who received adefovir (0.3 mg/kg/day [maximal dose 10 mg]) for at least 12 months (mean, 33.4 months; range, 12.4~58.3 months). The serum HBV DNA level and serologic markers were measured every 2 months. Results: The interval to a HBV DNA titer decrement (>1 $log_{10}$) was 1.2${\pm}$0.2 and 4.4${\pm}$5.2 months (p=0.185) for the entecavir and adefovir groups, respectively. The interval to a HBV DNA titer decrement (>2 $log_{10}$) was 2.4${\pm}$2.3 and 9.2${\pm}$7.3 months (p=0.025), for the entecavir and adefovir groups, respectively. Conclusion: The therapeutic efficacy of entecavir was favorable in children and adolescents, especially in shortening the interval to a >2 $log_{10}$ decrement in the HBV DNA titer. Long-term follow up is needed to determine the therapeutic efficacy of entecavir for lamivudine-resistant CHB in children and adolescents.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.2 no.2
• /
• pp.169-177
• /
• 1999

Purpose: To evaluate the efficacy of interferon alpha therapy with or without prednisolone in children with chronic hepatitis B. Methods: Twenty-eight children (22 boys, 6 girls, mean age 130 months) had seropositive results for HBsAg, HBeAg and HBV DNA; 11 had chronic persistent hepatitis and 17 had chronic active hepatitis. The patients were divided into two groups depending upon their inflammatory activity on liver biopsy, pretreatment serum ALT levels and HBV DNA levels. Fourteen children (group 1: chronic active hepatitis, ALT ${\geq}$ 100 IU/L and HBV DNA ${\leq}$ 100 pg/$300\;{\mu}L$) received interferon alpha 2a 5 $MU/m^2$ of body surface three times weekly for 6 months. Fourteen children (group 2: chronic persistent hepatitis or chronic active hepatitis with ALT < 100 IU/L or HBV DNA > 100 pg/$300\;{\mu}L$) received prednisolone in decreasing daily doses of 60 mg/$m^2$, 40 mg/$m^2$, and 20 mg/$m^2$, each for 2 weeks, followed after 2 weeks by interferon alpha 2a on the same schedule. At the end of therapy, 3 end points were analyzed: HBeAg seroconversion, serum ALT normalization rate and clearance of serum HBV DNA. Results: At the end of treatment, HBe antigen-to antibody seroconversion was higher but not more significant in group 1 than group 2 (71.4% vs. 50.0%). Only one patient in group 2 who lost HBeAg, also cleared HBsAg. ALT normalization was similar in both groups (64.3% in group 1 vs. 55.6% in group 2). Clearance of serum HBV DNA was observed in 78.6% of patients in group 1 and 64.3% in group 2, but no significant differences. Complete response was similarly achieved in both groups (57.1% in group 1 vs. 50.0% in group 2). Interferon alpha therapy with prednisolone priming was well tolerated and all children finished therapy. Conclusion: The combined therapy with prednisolone followed by interferon alpha may be safe and effective in inducing a serological and biochemical remission of the disease in approximately 50% of children with chronic hepatitis B and with a high level of viral replication and less active disease. However, a controlled study should be performed to confirm these results.

• Journal of Preventive Medicine and Public Health
• /
• v.33 no.3
• /
• pp.323-333
• /
• 2000

Objectives : Chronic HBsAg carriers are the principal source of infection for other susceptible people, and are themselves at high risk of developing serious liver diseases. In Korea, it has been estimated that 65-75% of the HBsAg positives remained as persistent carriers. Additionally, familial clustering of MBV infection has frequently been observed among carriers. Some would become progressive, chronic hepatitis patients, and others would not. The aim of this study was to evaluate the association between various factors, such as the duration of infection, type of virus, mutation of precore/core region in HBV, major histocompatibility class-I, and developing chronic liver diseases among familial HBV carriers. Methods : Chronic carrier status was identified by repeated serological tests for HBsAg at intervals of six months or more. A familial chronic carrier was defined when the disease was observed in a family member over two generations. Two families were recruited, among which a total of 20 chronic HBsAg carriers(11 carriers in No.1, and 9 in No.2 family) were identified. Data on the general characteristics and liver disease status were collected. Identification of the HBV-DNA was successful only for 13 subjects among the 20 carriers. Analysis of viral DNA in terms of subtype, pre-core and core region mutations was carried out. The type of major histocompatibility class-1 for the 13 subjects was also analysed. Results & Conclusions : Seven of 10 chronic HBV carriers of the 1st generation and one of 10 of the 2nd generation were clinical patients with chronic hepatitis, the others, three of the 1 st and nine of the 2nd generation, were asymptomatic carriers. This data indicates that the duration of HBV carriage is one of the major factors for disease severity. The subtype of HBsAg analysed using MBV-DNA identified in 13 carriers were adr, and the pattern of precore nonsense mutation in HBV-DNA was identical among family members, which meads that the same virus strains were transmitted between the family members. The association between the precore or core mutations in HBV-DNA and the disease severity was not observed. While it was suggested that a specific type of MHC class-I may be related to disease progression.