A Secreted Form of the Hepatitis E Virus ORF2 Protein: Design Strategy, Antigenicity and Immunogenicity

Zihao Chen; Shaoqi Guo; Guanghui Li; Dong Ying; Guiping Wen; Mujin Fang; Yingbin Wang; Zimin Tang; Zizheng Zheng; Ningshao Xia

doi:10.3390/v14102122

A Secreted Form of the Hepatitis E Virus ORF2 Protein: Design Strategy, Antigenicity and Immunogenicity

Viruses. 2022 Sep 26;14(10):2122. doi: 10.3390/v14102122.

Authors

Zihao Chen¹, Shaoqi Guo^{1

2}, Guanghui Li¹, Dong Ying^{1

2}, Guiping Wen³, Mujin Fang^{1

4

5}, Yingbin Wang^{1

5}, Zimin Tang^{1

4

5}, Zizheng Zheng^{1

5}, Ningshao Xia^{1

2

4

5

6}

Affiliations

¹ State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Public Health, Xiamen University, Xiamen 361005, China.
² School of Life Sciences, Xiamen University, Xiamen 361005, China.
³ United Diagnostic and Research Center for Clinical Genetics, School of Medicine & School of Public Health, Xiamen University, Xiamen 361005, China.
⁴ NMPA Key Laboratory for Research and Evaluation of Infectious Disease Diagnostic Technology, School of Public Health, Xiamen University, Xiamen 361005, China.
⁵ Xiang An Biomedicine Laboratory, Xiamen University, Xiamen 361005, China.
⁶ Research Unit of Frontier Technology of Structural Vaccinology, Chinese Academy of Medical Sciences, Xiamen 361005, China.

Abstract

Hepatitis E virus (HEV) is an important public health burden worldwide, causing approximately 20 million infections and 70,000 deaths annually. The viral capsid protein is encoded by open reading frame 2 (ORF2) of the HEV genome. Most ORF2 protein present in body fluids is the glycosylated secreted form of the protein (ORF2^S). A recent study suggested that ORF2^S is not necessary for the HEV life cycle. A previously reported efficient HEV cell culture system can be used to understand the origin and life cycle of ORF2^S but is not sufficient for functional research. A more rapid and productive method for yielding ORF2^S could help to study its antigenicity and immunogenicity. In this study, the ORF2^S (tPA) expression construct was designed as a candidate tool. A set of representative anti-HEV monoclonal antibodies was further used to map the functional antigenic sites in the candidates. ORF2^S (tPA) was used to study antigenicity and immunogenicity. Indirect ELISA revealed that ORF2^S (tPA) was not antigenically identical to HEV 239 antigen (p239). The ORF2^S-specific antibodies were successfully induced in one-dose-vaccinated BALB/c mice. The ORF2^S-specific antibody response was detected in plasma from HEV-infected patients. Recombinant ORF2^S (tPA) can act as a decoy to against B cells. Altogether, our study presents a design strategy for ORF2^S expression and indicates that ORF2^S (tPA) can be used for functional and structural studies of the HEV life cycle.

Keywords: B-cell decoy; ORF2; antigenicity; hepatitis E virus; immunogenicity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antibodies, Monoclonal / genetics
Capsid Proteins / genetics
Hepatitis E virus* / genetics
Hepatitis E*
Mice
Mice, Inbred BALB C
Open Reading Frames

Substances

Capsid Proteins
Antibodies, Monoclonal

Grants and funding

This research was funded by the National Natural Science Foundation of China, grant numbers 82071783 (Zizheng Zheng, School of Public Health, Xiamen University), 82171746 (Zimin Tang, School of Public Health, Xiamen University), and 82001757 (Guiping Wen, School of Medicine, Xiamen University); the Major Science and Technology Project for Significant New Drugs Creation, grant number 2018ZX09303005-002 (Ningshao Xia, School of Public Health, Xiamen University); the CAMS Innovation Fund for Medical Sciences, grant number 2019RU022 (Ningshao Xia, School of Public Health, Xiamen University); and the Fundamental Research Funds for the Central Universities, grant number 20720220006 (Ningshao Xia, School of Public Health, Xiamen University).