• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.361-368
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• 1998

The E2 protein of HCV (hepatitis C virus) is thought to have a potential role in the development of subunit vaccines and diagnostics. To express it by the insect cell/baculovirus expression (Bacu) system, we constructed a recombinant Autographa californica nuclear polyhedrosis virus (AcIL3E2), determined the most appropriate expression conditions in terms of host cell line and culture medium, and characterized the expressed HCV E2 protein. A culture system using Trichoplusia ni BTI-TN5Bl-4 cells and SF 900IISFM medium expressed a relatively high level of HCV E2 protein. It was revealed that its glycosylation properties and subcellular localization were almost the same as the ones in the mammalian cell expression system previously reported, suggesting the recombinant HCV E2 protein derived from our Bacu system can be utilized for development of a subunit vaccine and diagnostics. Interestingly, HCV E2 protein was not degraded at all even at 43 h post-heat shock in the heat shock-induced necrotic cells, probably due to its integration into the microsomal membrane, indicating that heat shock can be employed to purify HCV E2 protein.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.28-28
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• 2003

Hepatitis E virus (HEV), previously referred to as enterically transmitted non-A, non-B hepatitis, is responsible for sporadic infections as well as large epidemics of acute viral hepatitis in developing countries. The disease generally affects young adults and reportedly has a mortality rate of up to 20％ in infected pregnant women. HEV was once considered to be a member of the family Caliciviridae, but the unique genomic organization of HEV has led to the removal of HEV from the family and it was provisionally classified in an unassigned family of HEV-like viruses. In situ hybridization provides any cellular detail and histological architecture.[1] However, use of in situ hybridization is largely restricted to the laboratories because this technique is the greater technical complexity and expense compared with immunohistochemistry. Therefore, the objective of this study is to develop the immunohistochemistry for the detection of swine HEV from formalin-fixed, paraffin-embedded hepatic tissues. (omitted)

• Annals of Occupational and Environmental Medicine
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• v.34
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• pp.22.1-22.7
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• 2022

Background: Several cases of chloroform-induced hepatotoxicity have been reported worldwide, but only 2 cases have been reported in Korea. We encountered a case of toxic hepatitis due to chloroform exposure in February 2022 and report the diagnosis process and clinical findings. Case presentation: A 38-year-old employee in charge of the coating after washing (degreasing) at an automotive parts manufacturer complained of jaundice and was diagnosed with acute toxic hepatitis. After the initial diagnosis, he continued to work, his symptoms worsened, and he was hospitalized for 8 days. Liver ultrasonography (elastography) revealed acute hepatitis. The washing agent contained chloroform, which was not listed on the materials safety data sheet, and the concentrations of chloroform in the workplace were up to 4.7 times the time-weighted average. Conclusions: This patient showed typical toxic hepatitis with chloroform; further follow-up studies are required. Both employers and workers should be aware of information on toxic substances and take precautions to avoid exposure.

• BMB Reports
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• v.40 no.6
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• pp.1002-1008
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• 2007

PreS domain of Hepatitis B virus (HBV) surface antigen is a good candidate for an effective vaccine as it activates both B and T cells besides binding to hepatocytes. This report deals with overexpression and purification of adr subtype of surface antigen that is more prevalent in Pakistan. PreS region, comprising 119 aa preS1 region plus a 55 aa preS2 region plus 11 aa from the N-terminal S region, was inserted in pET21a+ vector, cloned in E. coli $DH5\alpha$ cells and expressed in E. coli BL21 codon+ cells. The conditions for over expression were optimized using different concentrations of IPTG (0.01-5 mM), and incubating the cells at different temperatures (23-$41^{\circ}C$) for different durations (0-6 h). The cells were grown under the given optimized conditions (0.5 mM IPTG concentration at $37^{\circ}C$ for 4 h), lysed by sonication and the protein was purified by ion exchange chromatography. On the average, 24.5 mg of recombinant protein was purified per liter of culture. The purified protein was later lyophilized and stored at $-80^{\circ}C$.

• BMB Reports
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• v.37 no.6
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• pp.735-740
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• 2004

Hepatitis C virus (HCV) is a causal agent of the chronic liver infection. To understand HCV morphogenesis, we studied the assembly of HCV structural proteins in insect cells. We constructed recombinant baculovirus expression vectors consisting of either HCV core alone, core-E1, or core-E1-E2. These structural proteins were expressed in insect cells and were examined to assemble into particles. Neither core-E1 nor core-E1-E2 was capable of assembling into virus-like particles (VLPs). It was surprising that the core protein alone was assembled into core-like particles. These particles were released into the culture medium as early as 2 days after infection. In our system, HCV structural proteins including envelope proteins did not assemble into VLPs. Instead, the core protein itself has the intrinsic capacity to assemble into amorphous core-like particles. Furthermore, released core particles were associated with HCV RNA, indicating that core proteins were assembled into nucleocapsids. These results suggest that HCV may utilize a unique core release mechanism to evade the hosts defense mechanism, thus contributing to the persistence of HCV infection.

• YAKHAK HOEJI
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• v.57 no.1
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• pp.43-54
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• 2013

Viral hepatitis is the inflammation of liver cells caused by viruses, and still one of the major health-care problems worldwide. A number of viruses to cause hepatitis are type A, B, C, D, E or G. Among these viruses leading to hepatitis, B and C are more troublesome being more prone to chronic illness which can cause the potentially fatal conditions of hepatocellular carcinoma (HCC) and/or liver failure. If immediate treatment is not initiated, liver transplant is the only option left. Over the past few decades there has been remarkable progress in diagnose and monitor all hepatitis virus infections for treatment and prevention. Nonetheless, important challenges remain to develop more effective and safe vaccines for prevention as well as antiviral agents to reduce viremia/viral load by inhibiting viral replication. The development and evaluation of antiviral agents through carefully designed clinical trials over the last 25 years has heralded a new dawn in the treatment of patients chronically infected with the hepatitis B and C viruses, but not so for the D virus. The introduction of Direct Acting Antivirals (DDAs) for the treatment of HBV carriers has permitted the long term use of these compounds for the continuous suppression of viral replication. This review aims to summarize the current status and development approaches of antiviral drugs for the treatment of viral hepatitis and future perspectives.

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

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.26-26
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• 2003

Hepatitis E virus (HEV) has been recognized as a major cause of enterically transmitted non-A, non-B hepatitis in many developing countries. The taxonomy of HEV is not clear and the virus remains unclassified. The objective of this study was to optimize conditions and procedures to detect swine HEV in formalin-fixed, paraffin-embedded tissues by nested RT-PCR and compare this detection method with in situ hybridization. (omitted)

• Journal of Microbiology and Biotechnology
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• v.18 no.10
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• pp.1722-1728
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• 2008

The natural course of chronic hepatitis B (CH-B) virus infection is reportedly variable, and the long-term outcomes in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B infection are distinct from HBeAg-positive chronic hepatitis. However, the molecular virological factors that contribute to the progression of liver disease in the south Indian setting remain largely unclear. We prospectively studied 679 consecutive patients for HBsAg, HBeAg, anti-HBe, and HBV DNA by qualitative PCR. Randomly selected samples were subjected to bidirectional sequencing to reveal core/precore variants. Of the total 679 chronic HBV cases investigated, 23% (154/679) were replicative HBV carriers. Furthermore, amongst the 560 HBV DNA samples analyzed, 26% (146/560) were viremic. Among the 154 HBeAg positive cases, HBV DNA was positive in 118 cases (77%), significantly (p<0.001) higher than the anti-HBe positive (7%) (28/406) cases. Significant increase in liver disease (p<0.01) with ALT enzyme elevation (p<0.001) was observed in both HBe and anti-HBe viremic cases. Interestingly, low frequencies of mutations were seen in the precore region of the HBV strains studied. HBV precore and core promoter variants were less often detected in subjects with "e" negative chronic HBV infection and, therefore, may not have a prognostic role in determining liver disease sequelae in this part of tropical India.

• Archives of Pharmacal Research
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• v.10 no.1
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• pp.18-24
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• 1987

Mouse monocolonal antibodies to Hepatitis B surface antien (HBsAg) were prepared and their functional capabilities tested by the method of solid phase enzyme linked immuno sorbent assay (ELISA). HBsAg binding studies inicated that one monoclonal antibody 6E-1-1 bound more HBsAg at a faster rate than the other monoclonal antibodies. Also, for the binding inhibition studies with the selected monoclonal antibody 6E-1-1, one monoclonal antibody 8D-3-6 didn't exhibit binding inhibition for HBsAg. Then, a simultaneous ELISA method was developed for the immunodiagnosis of HBsAg. Different combinations of two monoclonal antibodies as solid phase and horseradish peroxidase (HRPO) labeled phase were studied. The combination of monoclonal antibody of higher affinity constant (6E-1-1) immobilized in a solid phase and monoclonal antibody of lower affinity constant (8D-3-6) as a HRPO laeled phase was more sensitive when two monoclonal antibodies of different affinity constants for HBsAg were prepared.