Putative receptor-binding sites of hepatitis E virus.

Area of Science:

• Virology
• Molecular Biology
• Cell Biology

Background:

• Hepatitis E virus (HEV) infection is a significant global health concern.
• Understanding HEV cell entry mechanisms is crucial for developing antiviral strategies.
• The HEV structural protein p239, a truncated form, forms particles resembling HEV capsomeres.

Purpose of the Study:

• To investigate the role of the recombinant HEV protein p239 as a potential probe for the HEV receptor.
• To elucidate the specific domains of p239 involved in HEV cell binding and infection.

Main Methods:

• Purification of recombinant HEV p239 protein.
• Cell binding and penetration assays using HEV-susceptible cell lines.
• HEV infection inhibition assays.
• Monoclonal antibody (mAb) blocking studies targeting p239 domains.
• Site-directed mutagenesis of p239 domains.

Main Results:

• Purified p239 bound to and penetrated HEV-susceptible cell lines.
• p239 inhibited HEV infection of these cells.
• Binding involved both monomeric and dimeric domains of p239.
• Mutations in the dimeric domain significantly reduced p239 binding and HEV infection blocking capacity.
• Mutations in the monomeric domain did not affect binding or blocking capacity.

Conclusions:

• The HEV protein p239 can serve as a probe for the HEV receptor.
• The dimeric domain of p239 is critical for HEV cell binding and infection.
• HEV infection likely involves distinct receptor-binding sites, with the dimeric domain playing a key role.