Hepatitis E virus (HEV) is one of the most prevalent causes of acute viral hepatitis, but also one of the least diagnosed. There are about 20 million HEV infections, thus causing nearly 3.3 million symptomatic cases of hepatitis E. HEV infections occur globally and are most common in East and South Asia.
With a diameter of approximately 27-34 nm, HEV is a small, nonenveloped single-stranded, icosahedral RNA virus, whose phylogenetic analyses showed that it is the only member of the genus Hepevirus in the Hepeviridae family. HEV are closely linked to human diseases. Among them, genotypes 1 and 2 infect only humans, while genotypes 3 and 4 infect many animal species in addition to humans.
Three open reading frames (ORFs) are included in the HEV genome: ORF1 encodes a non-structural protein accountable for viral processing and replication; ORF2 encodes the capsid protein associated with viral assembly; ORF3 encodes a multifunctional protein involved in virion morphogenesis and release.
Development of HEV Vaccines
Hecolin
A recombinant vaccine has been discovered to prevent human infection with HEV (Hecolin, HEV 239), which is available in China but not yet approved in other countries.
The recombinant hepatitis E vaccine (Hecolin) consists of amino acids 368-606 of the HEV open reading frame 2 (ORF2) capsid protein from HEV genotype 1, which is expressed as an insoluble protein in Escherichia coli (E. coli) and self-assembles into virus-like particles (VLPs). The above-mentioned Hecolin involves aluminum-based adjuvants for improving antigen immunogenicity. Hecolin was developed and commercialized by Xiamen Innovative Biotechnology Co. located in Xiamen, China, and was approved in 2012 by NMPA (formerly CFDA).
A literature review outlines the production process of Hecolin (HEV 239) that is overexpressed in E. coli as the form of inclusion bodies. The inclusion bodies are harvested, washed with Triton-X100, and then denatured with 4 M urea; HEV 239 protein is purified by two polishing chromatography for a final purity of 95-98%. Pure HEV 239 protein was reassembled in its particles and absorbed into an aluminum adjuvant.
Yaohai Bio-Pharma Offers One-Stop CDMO Solution for HEV VLP Vaccine
Pipelines of HEV Vaccine
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Generic Name
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Brand Name/ Alternative Name
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Expression System
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Manufacturer
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Latest Stage
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Recombinant Hepatitis E vaccine
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Hecolin, 益可宁, HEV 239
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Escherichia coli
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Innovative Biotechnology
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Approved in China
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Recombinant Hepatitis E vaccine
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HEV P179
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Escherichia coli
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Changchun Institute of Biological Products
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Phase I
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Recombinant Hepatitis E vaccine
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Pending Update
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Pending Update
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Zydus Lifesciences
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Phase I
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Recombinant Hepatitis E vaccine
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Sar-55 ORF-2 protein
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Pending Update
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Army, GlaxoSmithKline
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Phase II (Suspended)
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HR
CS
DA
NL
FI
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DE
EL
IT
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NO
PL
PT
RO
RU
ES
SV
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ID
LV
LT
SR
SK
SL
UK
VI
ET
HU
TH
TR
FA
AF
MS
BE
MK
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