Construction of replication--defective recombinant adenoviruses expressing influenza virus hemagglutinin and study on its immune responses

HA gene of influenza virus A/FM/1/47 was amplified by RT-PCR and cloned into adenovirus shutter vector pAdTrack-CMV. The recombinant plasmid and adenovirus DNA was cotransformed into E. coli BJ5183 and the recombinant adenovirus genomic DNA was obtained through homologous recombination. The recombinant adenovirus was gained after transfecting 293 cell line with the genomic DNA. HA gene was confirmed to be integrated into the genome of recombinant adenovirusu by PCR. The expression of HA was detected in the 293 cells infected with recombinant adenovirus. ELISA results showed that systemic immune responses to influenza virus could be induced effectively through both intranasal and oral routes as well as SIgA. The immunization efficacy of intranasal route was superior to that of oral route. Mice immunized with recombinant adenovirus showed complete protection against a challenge with 10 LD_(50) of influenza virus A/FM/1/47 whereas all control mice died. The replication-defective recombinant adenovirus expressing influenza virus hemagglutinin had been consturcted and could produce favorable immune responses.