title: Hepatitis E Virus Produced from Cell Culture Has a Lipid Envelope.
abstract: The absence of a productive cell culture system hampered detailed analysis of the structure and protein composition of the hepatitis E virion. In this study, hepatitis E virus from a robust HEV cell culture system and from the feces of infected monkeys at the peak of virus excretion was purified by ultra-centrifugation. The common feature of the two samples after ultracentrifugation was that the ORF2 protein mainly remained in the top fractions. The ORF2 protein from cell culture system was glycosylated, with an apparent molecular weight of 88 kDa, and was not infectious in PLC/PRF/5 cells. The ORF2 protein in this fraction can bind to and protect HEV RNA from digestion by RNase A. The RNA-ORF2 product has a similar sedimentation coefficient to the virus from feces. The viral RNA in the cell culture supernatant was mainly in the fraction of 1.15 g/cm3 but that from the feces was mainly in the fraction of 1.21 g/cm3. Both were infectious in PLC/PRF/5 cells. And the fraction in the middle of the gradient (1.06 g/cm3) from the cell culture supernatant,but not that from the feces, also has ORF2 protein and HEV RNA but was not infectious in PLC/PRF/5.The infectious RNA-rich fraction from the cell culture contained ORF3 protein and lipid but the corresponding fraction from feces had no lipid and little ORF3 protein. The lipid on the surface of the virus has no effect on its binding to cells but the ORF3 protein interferes with binding. The result suggests that most of the secreted ORF2 protein is not associated with HEV RNA and that hepatitis E virus produced in cell culture differs in structure from the virus found in feces in that it has a lipid envelope.
authors.affiliation: National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun, 130012, China; Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Qi
authors.affiliation: Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Division of Medicine, University College London Medical School, London, WC1E 6BT, United Kingdom.
authors.forename: Tim J
authors.initials: TJ
authors.lastname: Harrison
authors.affiliation: Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China.
authors.forename: Weijin
authors.initials: W
authors.lastname: Huang
authors.affiliation: Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China.
authors.forename: Chenyan
authors.initials: C
authors.lastname: Zhao
authors.affiliation: National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun, 130012, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Kong
authors.affiliation: National Engineering Laboratory for AIDS Vaccine, Jilin University, Changchun, 130012, China.
authors.forename: Chunlai
authors.initials: C
authors.lastname: Jiang
authors.affiliation: Division of HIV/AIDS and Sexually-Transmitted Virus Vaccines, National Institutes for Food and Drug Control, Beijing, 100050, China.
authors.forename: Youchun
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D024202:Electrophoretic Mobility Shift Assay; D005243:Feces / Q000821:virology; D006023:Glycoproteins / Q000378:metabolism; D000882:Haplorhini; D016751:Hepatitis E / Q000821:virology; D016752:Hepatitis E virus / Q000378:metabolism* / Q000472:pathogenicity; D008563:Membrane Lipids / Q000737:chemistry*; D011485:Protein Binding; D012367:RNA, Viral / Q000378:metabolism; D012015:Reference Standards; D014461:Ultracentrifugation; D014764:Viral Proteins / Q000378:metabolism; D014771:Virion / Q000378:metabolism
chemical_list: D006023:Glycoproteins; D008563:Membrane Lipids; D012367:RNA, Viral; D014764:Viral Proteins; C050629:viral envelope lipids