scholarly journals Presence of Replicating Virus in Recombinant Hepadnavirus Stocks Results from Recombination and Can Be Eliminated by the Use of a Packaging Cell Line

2003 ◽  
Vol 77 (5) ◽  
pp. 2873-2881 ◽  
Author(s):  
Uta Klöcker ◽  
Heike Oberwinkler ◽  
Timo Kürschner ◽  
Ulrike Protzer
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Wild Type Virus ◽  
Recombinant Hepatitis ◽  
Type Virus ◽  
Wild Type ◽  
Viral Genomes ◽  
B Virus ◽  
Viral Sequences

ABSTRACT Mutant hepatitis B viruses are useful tools to study the viral life cycle and viral pathogenesis. Furthermore, recombinant hepatitis B viruses are candidate vectors for liver-directed gene therapy. Because wild-type viruses present in recombinant or mutant virus stocks may falsify experimental results and are detrimental for a viral vector, we investigated whether and to what extent wild-type virus is present in recombinant virus stocks and where it originates from. We took advantage of the duck model of hepatitis B virus infection which allows very sensitive detection of replication-competent viruses by infection of primary duck hepatocytes or of ducklings in vivo. Recombinant hepatitis B virus stocks contained significant amounts of wild-type viruses, which were most probably generated by homologous recombination between plasmids containing homologous viral sequences. In addition, replication-competent viral genomes were reconstituted from plasmids which contained replication-deficient but redundant viral sequences. Using a stable cell line for packaging of deficient viral genomes, no wild-type virus was detected, neither by infection of primary hepatocytes nor in vivo.

A novel hepatitis B virus mutant coexisting with wild type virus in a carrier with negative HBsAg yet positive HBeAg and anti-HBs

2009 ◽  
Vol 46 (4) ◽  
pp. 363-366 ◽  
Author(s):  
Yi-Hua Zhou ◽  
Jianxin Zhou ◽  
Lei Li ◽  
Yongchun Bi ◽  
Yong Liu ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
B Virus ◽  
Virus Mutant ◽  
Positive Hbeag

scholarly journals Enrichment of a Precore-Minus Mutant of Duck Hepatitis B Virus in Experimental Mixed Infections

1999 ◽  
Vol 73 (5) ◽  
pp. 3616-3622 ◽  
Author(s):  
Yong-Yuan Zhang ◽  
Jesse Summers
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Mutant Virus ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Duck Hepatitis B Virus ◽  
Duck Hepatitis ◽  
B Virus ◽  
Precore Mutant

ABSTRACT A precore-deficient mutant of duck hepatitis B virus (DHBV) produced by site-directed mutagenesis was tested for its ability to compete with wild-type virus in a mixed infection of 3-day-old ducklings. The mutation was shown to produce a cis-acting defect, resulting in a replication rate that was about one-half that of wild-type virus. Accordingly, wild-type virus was rapidly selected during the spread of infection. During the chronic phase of the infection, however, two selection patterns were seen. In 4 of 10 ducks, the wild-type virus slowly replaced the precore mutant. In another four ducks, the precore mutant virus slowly replaced the wild-type virus. In the remaining two ducklings, ratios of wild-type and precore mutant virus fluctuated, with wild-type virus slowly predominating. The replacement of wild-type virus was not due to the emergence of a rapidly replicating variant of the precore mutant, since genomes cloned from the infected ducks retained their original replication defect. Replacement of wild-type virus, however, correlated with elevated anti-core antibody titers, which continued to increase with time. The selection of a precore-negative strain of DHBV may be analogous to the selection for precore mutants of HBV during chronic hepatitis in humans.

scholarly journals Interferon gene transfer by a hepatitis B virus vector efficiently suppresses wild-type virus infection

1999 ◽  
Vol 96 (19) ◽  
pp. 10818-10823 ◽  
Author(s):  
U. Protzer ◽  
M. Nassal ◽  
P.-W. Chiang ◽  
M. Kirschfink ◽  
H. Schaller
Keyword(s):  
Hepatitis B Virus ◽  
Gene Transfer ◽  
Virus Infection ◽  
Hepatitis B ◽  
Virus Vector ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
B Virus ◽  
Interferon Gene

scholarly journals Efficacies of Entecavir against Lamivudine-Resistant Hepatitis B Virus Replication and Recombinant Polymerases In Vitro

2002 ◽  
Vol 46 (8) ◽  
pp. 2525-2532 ◽  
Author(s):  
S. Levine ◽  
D. Hernandez ◽  
G. Yamanaka ◽  
S. Zhang ◽  
R. Rose ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Cross Resistance ◽  
Wild Type ◽  
Resistance Mutations ◽  
Hbv Replication ◽  
B Virus ◽  
Inhibition Studies

ABSTRACT Entecavir (ETV) is a potent and selective inhibitor of hepatitis B virus (HBV) replication in vitro and in vivo that is currently in clinical trials for the treatment of chronic HBV infections. A major limitation of the current HBV antiviral therapy, lamivudine (3TC), is the emergence of drug-resistant HBV in a majority of treated patients due to specific mutations in the nucleotide binding site of HBV DNA polymerase (HBV Pol). To determine the effects of 3TC resistance mutations on inhibition by ETV triphosphate (ETV-TP), a series of in vitro studies were performed. The inhibition of wild-type and 3TC-resistant HBV Pol by ETV-TP was measured using recombinant HBV nucleocapsids, and compared to that of 3TC-TP. These enzyme inhibition studies demonstrated that ETV-TP is a highly potent inhibitor of wild-type HBV Pol and is 100- to 300-fold more potent than 3TC-TP against 3TC-resistant HBV Pol. Cell culture assays were used to gauge the potential for antiviral cross-resistance of 3TC-resistant mutants to ETV. Results demonstrated that ETV inhibited the replication of 3TC-resistant HBV, but 20- to 30-fold higher concentrations were required. To gain further perspective regarding the potential therapeutic use of ETV, its phosphorylation was examined in hepatoma cells treated with extracellular concentrations representative of drug levels in plasma in ETV-treated patients. At these concentrations, intracellular ETV-TP accumulated to levels expected to inhibit the enzyme activity of both wild-type and 3TC-resistant HBV Pol. These findings are predictive of potent antiviral activity of ETV against both wild-type and 3TC-resistant HBV.

scholarly journals IL-17 Activates the IL-6/STAT3 Signal Pathway in the Proliferation of Hepatitis B Virus-Related Hepatocellular Carcinoma

2017 ◽  
Vol 43 (6) ◽  
pp. 2379-2390 ◽  
Author(s):  
Zongqiang Hu ◽  
Ding Luo ◽  
Dongdong Wang ◽  
Linjie Ma ◽  
Yingpeng Zhao ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Knockout Mice ◽  
Hepg2 Cells ◽  
Wild Type ◽  
B Virus ◽  
And Migration ◽  
Proliferation And Migration

Background/Aims: We performed this study to determine the role of IL-17 in the immune microenvironment of hepatitis B virus- (HBV-) related hepatocellular carcinoma (HCC). Methods: HepG2 cells were treated with IL-17, STAT3 inhibitor S31-201 or IL-6 neutralizing monoclonal antibody (IL-6 mAb). Cell proliferation and migration were compared using the Cell Counting kit-8 (CCK-8) and Transwell assays, respectively. Real-time quantitative PCR (RT-qPCR), Western Blot, ELISA, immunofluorescence and histological staining were used for determining the expression levels of IL-17, IL-6, MCP-1, CCL5, VEGF, STAT3 and p-STAT3. HCC xenograft models were constructed in wild type and IL-17 knockout mice to clarify the effects of IL-17 on HCC in vivo. Results: Exogenous IL-17 enhanced the proliferation and migration of HepG2 cells, and it activated the phosphorylation of STAT3. RT-qPCR and ELISA showed that IL-17 promoted the expression of IL-6. The CCK-8 and Transwell assays showed that S31-201 or IL-6 mAb remarkably reversed the promotion effects of proliferation and migration by exogenous IL-17 in HepG2 cells. Additionally, IL-6 could promote the phosphorylation of STAT3, while IL-6 mAb acted as an inhibitor, and exogenous IL-17 could neutralize the inhibitory effects of IL-6 mAb. In vivo, compared to the wild type mice, the tumor volume, weight, density and size were decreased in IL-17 knockout mice. Additionally, the expression levels of p-STAT3, IL-6, MCP-1, CCL5 and VEGF decreased in IL-17 knockout mice. Conclusions: IL-17 can enhance the proliferation of HepG2 cells in vitro and in vivo via activating the IL-6/STAT3 pathway. Therefore, the IL-17/IL-6/STAT3 signaling pathway is a potential therapeutic target for HBV-related HCC.

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