Characterization of self-assembled virus-like particles of dromedary camel hepatitis e virus generated by recombinant baculoviruses

• Native and small virus-like particles (VLPs) of DcHEV were produced by a recombinant baculovirus system.
• The DcHEV-LPs showed antigenic cross-reactivity against G1–G5 and G6 HEV more strongly than against ferret or rat HEV.
• The DcHEV have the same serotype as G1, G3 and G4 HEVs.

Dromedary camel hepatitis E virus (DcHEV), a novel hepatitis E virus, has been identified in dromedary camels in Dubai, United Arab Emirates. The antigenicity, pathogenicity and epidemiology of this virus have been unclear. Here we first used a recombinant baculovirus expression system to express the 13 and 111 N-terminus amino-acid-truncated DcHEV ORF2 protein in insect Tn5 cells, and we obtained two types of virus-like particles (VLPs) with densities of 1.300 g/cm3 and 1.285 g/cm3, respectively. The small VLPs (Dc4sVLPs) were estimated to be 24 nm in diameter, and were assembled by a protein with the molecular mass 53 kDa. The large VLPs (Dc3nVLPs and Dc4nVLPs) were 35 nm in diameter, and were assembled by a 64-kDa protein. An antigenic analysis demonstrated that DcHEV was cross-reactive with G1, G3–G6, ferret and rat HEVs, and DcHEV showed a stronger cross-reactivity to G1 G3–G6 HEV than it did to rat and ferret HEV. In addition, the antibody against DcHEV-LPs neutralized G1 and G3 HEV in a cell culture system, suggesting that the serotypes of these HEVs are identical. We also found that the amino acid residue Met-358 affects the small DcHEV-LPs assembly.