Abstract：To investigate the immunogenicity of eukaryotic expression plasmid of duck hepatitis B virus core antigen ( DHBcAg) in mice, we first analyzed the hydrophilic and hydrophobic characteristics of the amino acid sequence of DHBcAg by bioinformatics with the Vector NTI Suite software, and constructed the eukaryotic expression plasmids of the complete ( E-DHBc 263) and partial sequences ( only the hydrophilic part, E-DHBc 180) of DHBcAg gene. The results showed that both plasmids expressed DHBcAg in transfected COS7 cells detected by indirect immunofluorescence. The prokaryotic expression plasmids, p-DHBc 263 and p-DHBc 180, were constructed to express DHBcAg for DHBcAb detection, but only p-DHBc180-expressed DHBcAg could be detected by Western blot. Then we immunized BALB/ c mice with E-DHBc 180 and E-DHBc 263. DHBcAb titers in sera from immunized mice were detected by enzyme-linked immunosorbent assay ( ELISA) on the plates coated with prokaryotically expressed DHBcAg. The mice primed and boosted with E-DHBc180 produced DHBcAb, and titers were 1∶100-1∶400, while in E-DHBc 263-immunized mice DHBcAb level was belowthe detection level. It suggests that E-DHBc 180 could be used as DHBcAg DNA vaccine for further research in its effects on DHBV infection.
