OBJECTIVETo construct a replication-defective recombinant adenovirus expressing the ORF2 (112-660aa) antigen of hepatitis E virus (HEV) and evaluate its immunization effect in BALB/c mice by mucosal inoculation.

METHODSThe HEV ORF2 gene encoding for 112-660aa was amplified from plasmid pUC-HEV and inserted into the transfer vector pTrack-CMV. The recombinant plasmid and adenoviral backbone plasmid pAdEasy-1 were co-transformed into E. coli strain BJ5183. Taking the advantage of the high efficient homologous recombination machinery presented in bacteria, the recombinant adenovirus backbone plasmid was generated in BJ5183, and then was transfected into 293 cells. Recombinant Adenoviruses were propagated in 293 cells with high titers. 8-week-old BALB/c mice were inoculated intraperitoneally and intranasally with 10(7) pfu recombinant adenovirus each on weeks 0, 3, 5, 7, 10.

RESULTSBoth groups of mice induced humoral IgG immune response with the highest titers 1:1,000 and 1:10,000 each. Only the group inoculated intranasally could induce mucosal IgA immune response.

CONCLUSIONSThe adenoviral recombinant can stimulate specific humoral and mucosal immune response in mice and is potentially to be used as a candidate vaccine for the treatment of HEV infection.