A broadly cross-reactive monoclonal antibody against hepatitis E virus capsid antigen

• Published in: Applied Microbiology and Biotechnology
• Main Authors: Kubickova, Barbara, Schenk, Jörg A, Ramm, Franziska, Marcinkevičiūtė, Kornelija, Reetz, Jochen, Dremsek, Paul, Tamošiūnas, Paulius Lukas, Čepulytė, Laima, Trinh, Hoai Anh, Scholz, Johannes, Memczak, Henry, Hovestädt, Marc, Ryll, René, Petraitytė-Burneikienė, Rasa, Corman, Victor M, Andersson, Anika, Becher, Dietmar, Groschup, Martin H, Kubick, Stefan, Sellrie, Frank, Johne, Reimar, Ulrich, Rainer G
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Cell-free synthesis; Cross-reactivity; HEV-1; HEV-2; HEV-3; HEV-4; HEV-7; Hepatitis E virus; Monoclonal antibody; batHEV; cvHEV; ratHEV; Common vole
• Online Access: https://repository.vu.lt/VU:ELABAPDB109704309&prefLang=en_US

To generate a hepatitis E virus (HEV) genotype 3 (HEV-3)-specific monoclonal antibody (mAb), the Escherichia coli-expressed carboxy-terminal part of its capsid protein was used to immunise BALB/c mice. The immunisation resulted in the induction of HEV-specific antibodies of high titre. The mAb G117-AA4 of IgG1 isotype was obtained showing a strong reactivity with the homologous E. coli, but also yeast-expressed capsid protein of HEV-3. The mAb strongly cross-reacted with ratHEV capsid protein derivatives produced in both expression systems and weaker with an E. coli-expressed batHEV capsid protein fragment. In addition, the mAb reacted with capsid protein derivatives of genotypes HEV-2 and HEV-4 and common vole hepatitis E virus (cvHEV), produced by the cell-free synthesis in Chinese hamster ovary (CHO) and Spodoptera frugiperda (Sf21) cell lysates. Western blot and line blot reactivity of the mAb with capsid protein derivatives of HEV-1 to HEV-4, cvHEV, ratHEV and batHEV suggested a linear epitope. Use of truncated derivatives of ratHEV capsid protein in ELISA, Western blot, and a Pepscan analysis allowed to map the epitope within a partially surface-exposed region with the amino acid sequence LYTSV. The mAb was also shown to bind to human patient-derived HEV-3 from infected cell culture and to hare HEV-3 and camel HEV-7 capsid proteins from transfected cells by immunofluorescence assay. The novel mAb may serve as a useful tool for further investigations on the pathogenesis of HEV infections and might be used for diagnostic purposes. KEY POINTS: • The antibody showed cross-reactivity with capsid proteins of different hepeviruses. • The linear epitope of the antibody was mapped in a partially surface-exposed region. • The antibody detected native HEV-3 antigen in infected mammalian cells.