Protection of cynomolgus monkeys against HEV infection by oral administration of recombinant hepatitis E virus-like particles.

Hepatitis E virus (HEV) is an important causative agent of enterically-transmitted hepatitis. Successful vaccine development is crucial in controlling global HEV infection. HEV capsid protein, with 111 amino acids truncated at the N-terminus, was efficiently expressed in the baculovirus expression system. Expressed protein spontaneously assembled into virus-like particles (VLPs) and was released into culture medium. When cynomolgus monkeys were orally inoculated with 10mg of purified rHEV VLPs, serum IgM, IgG, and IgA responses were observed. All these antibody responses were obtained without adjuvants. When the monkeys were challenged with native HEV by intravenous injection, they were protected against infection or developing hepatitis. These results suggested that recombinant HEV (rHEV) VLPs can be a candidate for the oral hepatitis E vaccine.