Prophylactic Hepatitis E Vaccines: Antigenic Analysis and Serological Evaluation

Abstract

Hepatitis E virus (HEV) infection causes sporadic outbreaks of acute hepatitis worldwide. HEV was previously considered to be restricted to resource-limited countries with poor sanitary conditions, but increasing evidence implies that HEV is also a public health problem in developed countries and regions. Fortunately, several vaccine candidates based on virus-like particles (VLPs) have progressed into the clinical development stage, and one of them has been approved in China. This review provides an overview of the current HEV vaccine pipeline and future development with the emphasis on defining the critical quality attributes for the well-characterized vaccines. The presence of clinically relevant epitopes on the VLP surface is critical for eliciting functional antibodies against HEV infection, which is the key to the mechanism of action of the prophylactic vaccines against viral infections. Therefore, the epitope-specific immunochemical assays based on monoclonal antibodies (mAbs) for HEV vaccine antigen are critical methods in the toolbox for epitope characterization and for in vitro potency assessment. Moreover, serological evaluation methods after immunization are also discussed as biomarkers for clinical performance. The vaccine efficacy surrogate assays are critical in the preclinical and clinical stages of VLP-based vaccine development.

Immunogenicity of gold nanoparticle-based truncated ORF2 vaccine in mice against Hepatitis E virus

“…4 b). It has been observed that 54 kDa protein can form virus-like particles that enhances their immunogenic potential (Chattopadhyay et al 2017 , Gupta et al 2020 , Li et al 2020 ). The antibody response is dependent on the neutralization epitopes located at C-terminus of ORF2 (E2, 459-606aa) and bigger protein HEV239 (298-606aa) also contains an additional neutralization epitope (Zhao et al 2015 ).…”

The Risk of Transfusion-Transmitted Hepatitis E Virus: Evidence from Seroprevalence Screening of Blood Donations

“…Therefore, prophylactic vaccination could potentially be an effective method to protect people from HEV infection. Several vaccine candidates based on virus-like particles (VLPs) have progressed into the clinical development stage, and one of them currently approved in China, with evidence on safety and efficacy including in pregnant women [ 30 ].…”

Structural and molecular biology of hepatitis E virus

“…The commercial Hecolin HEV vaccine, based on a recombinant E. coli -expressed capsid protein p239, has demonstrated its safety and efficacy in a large-scale phase III clinical trial [70] and is approved and licensed for use in China in 2012 [71] . Furthermore, the Hecolin vaccine is currently undergoing a phase IV clinical trial to assess the safety, immunogenicity, and effectiveness in pregnant women in rural areas of Bangladesh [72] .…”