Use of S17 fragment containing hepatitis E virus infectious clones in cell culture experiments: The fine print does matter

2018 ◽  
Vol 25 (9) ◽  
pp. 1105-1105 ◽  
Author(s):  
S. Sridhar
Keyword(s):  
Cell Culture ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Infectious Clones ◽  
Fine Print

scholarly journals Cell Culture Models for Hepatitis E Virus

Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 608 ◽  
Author(s):  
Rebecca Menhua Fu ◽  
Charlotte Caroline Decker ◽  
Viet Loan Dao Thi
Keyword(s):  
Cell Culture ◽  
Life Cycle ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Cellular Systems ◽  
Advantages And Disadvantages ◽  
Infectious Clones ◽  
Cell Culture Systems ◽  
Culture Models ◽  
Cell Culture Models

Despite a growing awareness, hepatitis E virus (HEV) remains understudied and investigations have been historically hampered by the absence of efficient cell culture systems. As a result, the pathogenesis of HEV infection and basic steps of the HEV life cycle are poorly understood. Major efforts have recently been made through the development of HEV infectious clones and cellular systems that significantly advanced HEV research. Here, we summarize these systems, discussing their advantages and disadvantages for HEV studies. We further capitalize on the need for HEV-permissive polarized cell models to better recapitulate the entire HEV life cycle and transmission.

scholarly journals Cell Culture Isolation and Whole Genome Characterization of Hepatitis E Virus Strains from Wild Boars in Germany

2021 ◽  
Vol 9 (11) ◽  
pp. 2302
Author(s):  
Katja Schilling-Loeffler ◽  
Oliver Viera-Segura ◽  
Victor Max Corman ◽  
Julia Schneider ◽  
Ashish K. Gadicherla ◽  
...  
Keyword(s):  
Cell Culture ◽  
Wild Boar ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Enriched Library ◽  
Genome Copy ◽  
Genotype 3 ◽  
Wild Boars ◽  
Copy Numbers ◽  
Cell Culture Isolation

Infection with hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. The HEV genotype 3 can be zoonotically transmitted from animals to humans, with wild boars representing an important reservoir species. Cell culture isolation of HEV is generally difficult and mainly described for human isolates so far. Here, five sera and five liver samples from HEV-RNA-positive wild boar samples were inoculated onto PLC/PRF/5 cells, incubated for 3 months and thereafter passaged for additional 6 weeks. As demonstrated by RT-qPCR, immunofluorescence and immune electron microscopy, virus was successfully isolated from two liver samples, which originally contained high HEV genome copy numbers. Both isolates showed slower growth than the culture-adapted HEV strain 47832c. In contrast to this strain, the isolated strains had no insertions in their hypervariable genome region. Next generation sequencing using an HEV sequence-enriched library enabled full genome sequencing. Strain Wb108/17 belongs to subtype 3f and strain Wb257/17 to a tentative novel subtype recently described in Italian wild boars. The results indicate that HEV can be successfully isolated in cell culture from wild boar samples containing high HEV genome copy numbers. The isolates may be used further to study the zoonotic potential of wild boar-derived HEV subtypes.

scholarly journals The Capsid (ORF2) Protein of Hepatitis E Virus in Feces Is C-Terminally Truncated

Pathogens ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 24
Author(s):  
Takashi Nishiyama ◽  
Koji Umezawa ◽  
Kentaro Yamada ◽  
Masaharu Takahashi ◽  
Satoshi Kunita ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cell Culture ◽  
Structure Prediction ◽  
Hepatitis E Virus ◽  
Culture Media ◽  
Molecular Size ◽  
Hepatitis E ◽  
Terminal Region ◽  
Translation Product ◽  
Orf2 Protein

The hepatitis E virus (HEV) is a causative agent of hepatitis E. HEV virions in circulating blood and culture media are quasi-enveloped, while those in feces are nonenveloped. The capsid (ORF2) protein associated with an enveloped HEV virion is reported to comprise the translation product of leucine 14/methionine 16 to 660 (C-terminal end). However, the nature of the ORF2 protein associated with fecal HEV remains unclear. In the present study, we compared the molecular size of the ORF2 protein among fecal HEV, cell-culture-generated HEV (HEVcc), and detergent-treated protease-digested HEVcc. The ORF2 proteins associated with fecal HEV were C-terminally truncated and showed the same size as those of the detergent-treated protease-digested HEVcc virions (60 kDa), in contrast to those of the HEVcc (68 kDa). The structure prediction of the ORF2 protein (in line with previous studies) demonstrated that the C-terminal region (54 amino acids) of an ORF2 protein is in flux, suggesting that proteases target this region. The nonenveloped nondigested HEV structure prediction indicates that the C-terminal region of the ORF2 protein moves to the surface of the virion and is unnecessary for HEV infection. Our findings clarify the maturation of nonenveloped HEV and will be useful for studies on the HEV lifecycle.

scholarly journals Activities of Thrombin and Factor Xa Are Essential for Replication of Hepatitis E Virus and Are Possibly Implicated in ORF1 Polyprotein Processing

2018 ◽  
Vol 92 (6) ◽  
Author(s):  
Gayatri D. Kanade ◽  
Kunal D. Pingale ◽  
Yogesh A. Karpe
Keyword(s):  
Cell Culture ◽  
Cell Line ◽  
Liver Cell ◽  
Serine Proteases ◽  
Hepatitis E Virus ◽  
Factor Xa ◽  
Hepatitis E ◽  
Cleavage Sites ◽  
Polyprotein Processing ◽  
Liver Cell Line

ABSTRACTHepatitis E virus (HEV) is a clinically important positive-sense RNA virus. The ORF1 of HEV encodes a nonstructural polyprotein of 1,693 amino acids. It is not clear whether the ORF1 polyprotein (pORF1) is processed into distinct enzymatic domains. Many researchers have attempted to understand the mechanisms of pORF1 processing. However, these studies gave various results and could never convincingly establish the mechanism of pORF1 processing. In this study, we demonstrated the possible role of thrombin and factor Xa in pORF1 processing. We observed that the HEV pORF1 polyprotein bears conserved cleavage sites of thrombin and factor Xa. Using a reverse genetics approach, we demonstrated that an HEV replicon having mutations in the cleavage sites of either thrombin or factor Xa could not replicate efficiently in cell culture. Further, we demonstratedin vitroprocessing when we incubated recombinant pORF1 fragments with thrombin, and we observed the processing of pORF1 polyprotein. The treatment of a liver cell line with a serine protease inhibitor as well as small interfering RNA (siRNA) knockdown of thrombin and factor Xa resulted in significant reduction in the replication of HEV. Thrombin and factor Xa have been well studied for their roles in blood clotting. Both of these proteins are believed to be present in the active form in the blood plasma. Interestingly, in this report, we demonstrated the presence of biologically active thrombin and factor Xa in a liver cell line. The results suggest that factor Xa and thrombin are essential for the replication of HEV and may be involved in pORF1 polyprotein processing of HEV.IMPORTANCEHepatitis E virus (HEV) causes a liver disorder called hepatitis in humans, which is mostly an acute and self-limiting infection in adults. A high mortality rate of about 30% is observed in HEV-infected pregnant women in developing countries. There is no convincing opinion about HEV ORF1 polyprotein processing owing to the variability of study results obtained so far. HEV pORF1 has cleavage sites for two host cellular serine proteases, thrombin and factor Xa, that are conserved among HEV genotypes. For the first time, this study demonstrated that thrombin and factor Xa cleavage sites on HEV pORF1 are obligatory for HEV replication. Intracellular biochemical activities of the said serine proteases are also essential for efficient HEV replication in cell culture and must be involved in pORF1 processing. This study sheds light on the presence and roles of clotting factors with respect to virus replication in the cells.

scholarly journals Robust hepatitis E virus infection and transcriptional response in human hepatocytes

2020 ◽  
Vol 117 (3) ◽  
pp. 1731-1741 ◽  
Author(s):  
Daniel Todt ◽  
Martina Friesland ◽  
Nora Moeller ◽  
Dimas Praditya ◽  
Volker Kinast ◽  
...  
Keyword(s):  
Cell Culture ◽  
Hepatitis E Virus ◽  
Hepatoma Cell ◽  
Hepatitis E ◽  
Human Hepatocytes ◽  
Cell Culture Model ◽  
Genotype 3 ◽  
Human Hepatoma Cell ◽  
Culture Model ◽  
Viral Titers

Hepatitis E virus (HEV) is the causative agent of hepatitis E in humans and the leading cause for acute viral hepatitis worldwide. The virus is classified as a member of the genus Orthohepevirus A within the Hepeviridae family. Due to the absence of a robust cell culture model for HEV infection, the analysis of the viral life cycle, the development of effective antivirals and a vaccine is severely limited. In this study, we established a protocol based on the HEV genotype 3 p6 (Kernow C-1) and the human hepatoma cell lines HepG2 and HepG2/C3A with different media conditions to produce intracellular HEV cell culture-derived particles (HEVcc) with viral titers between 105 and 106 FFU/mL. Viral titers could be further enhanced by an HEV variant harboring a mutation in the RNA-dependent RNA polymerase. These HEVcc particles were characterized in density gradients and allowed the trans-complementation of subgenomic reporter HEV replicons. In addition, in vitro produced intracellular-derived particles were infectious in liver-humanized mice with high RNA copy numbers detectable in serum and feces. Efficient infection of primary human and swine hepatocytes using the developed protocol could be observed and was inhibited by ribavirin. Finally, RNA sequencing studies of HEV-infected primary human hepatocytes demonstrated a temporally structured transcriptional defense response. In conclusion, this robust cell culture model of HEV infection provides a powerful tool for studying viral–host interactions that should facilitate the discovery of antiviral drugs for this important zoonotic pathogen.

Replication of hepatitis E virus in three-dimensional cell culture

2013 ◽  
Vol 187 (2) ◽  
pp. 327-332 ◽  
Author(s):  
A. Berto ◽  
W.H.M. Van der Poel ◽  
R. Hakze-van der Honing ◽  
F. Martelli ◽  
R.M. La Ragione ◽  
...  
Keyword(s):  
Cell Culture ◽  
Hepatitis E Virus ◽  
Three Dimensional ◽  
Hepatitis E ◽  
Dimensional Cell

scholarly journals Cell Culture of Sporadic Hepatitis E Virus in China

1999 ◽  
Vol 6 (5) ◽  
pp. 729-733 ◽  
Author(s):  
Rutong Huang ◽  
Derong Li ◽  
Shaojing Wei ◽  
Qinghong Li ◽  
Xitong Yuan ◽  
...  
Keyword(s):  
Cell Culture ◽  
Hepatitis E Virus ◽  
Hepatitis E ◽  
Biological Properties ◽  
Isolation And Identification ◽  
Successful Isolation ◽  
Human Lung Carcinoma ◽  
A Cell ◽  
Human Lung Carcinoma Cell ◽  
Relationship Of

ABSTRACT The isolation and identification of the 87A strain of epidemic hepatitis E virus (HEV) by means of cell culturing have been described previously. This paper reports the successful isolation of a sporadic HEV strain (G93-2) in human lung carcinoma cell (A549) cultures. The etiology, molecular and biological properties, and serological relationship of this new strain to other, epidemic HEV strains are described. The propagation of both sporadic and epidemic HEV strains in a cell culture system will facilitate vaccine research.

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