Supporting data for “Applications of Hepatitis E Virus-Like Particles”

Due to the low genomic sequence homology between rHEV and bHEV, rHEV was long thought to be non-infectious to humans. In 2018, the first rHEV infection of a human wasidentified in a liver transplant recipient, challenging the conventional view that HEV infection in humans was limited to bHEV variants only. Since then, sporadic human rHEV cases have been documented across Spain, mainland China, Thailand, Canada, Germany and France, indicating an emerging global zoonotic potential of rHEV.</p><p dir="ltr">Current commercial clinical assays for HEV antibody detection are established based on bHEV antigens, which show low diagnostic sensitivity for rHEV infection and cannot differentiate prior infections caused by bHEV and rHEV.

These technical limitations prevent large-scale high-throughput screening and risk factor analysis for rHEV infection.</p><p dir="ltr">In this study, truncated ORF2 peptides of bHEV and rHEV were prepared using an Escherichia coliexpression system, and recombinant antigens with excellent immunogenicity and the capacity to self-assembleinto virus like particles were successfully obtained. Based on these antigens, a parallel immunoglobulin G (IgG) EIA system was established to simultaneously detect and accurately distinguish specific antibodies against bHEV and rHEV.

This detection system was further applied to analyse the seroprevalence of rHEV IgG among solid organ transplant recipients and immunocompetent individuals, and to compare the regional serological characteristics of bHEV and rHEV in populations from Hong Kong, Shenzhen and Hainan regions.</p><p dir="ltr">This study also established a stable virus-like particle (VLP)cell binding assay platform based on the specific binding ability of VLPs to host cell surface.

This system overcomes the technical bottlenecks of low in vitro replication efficiency and poor performanceof wild-type HEV in conventional neutralization assays, and provides a reliable in vitro experimental basis for subsequent evaluation of the neutralizing and blocking activity of monoclonal and polyclonal antibodies against HEV.</p><p dir="ltr">Hecolin, a licensed HEV vaccine in China, is designed based on the recombinantbHEV-A1 p239 peptide and provides effective protection against conventional bHEV strains.

However, animal challenge experiments have verified that this vaccine cannot prevent rHEV infection. To solve this problem, a novel bHEV/rHEV bivalent vaccine candidate was constructed in this study. The results demonstrated that the bivalent vaccine could provide efficient protection against both bHEV and rHEV infection.

Vaccination induced balanced bHEV?specific and rHEV?specific IgG responses in vivo. Furthermore, the bivalent vaccine could induce a comprehensive and broad-spectrumT-cell immune response, supporting its potential as a novel broad-spectrum HEV vaccine.</p>