Construction of a recombinant bacmid DNA containing influenza A virus hemagglutinin gene using a site-specific transposition mechanism

Introduction: In recent years, influenza viruses have caused moderate to severe infections all around the world while so far there is no influenza vaccine that can protect people with only one dose of injection. In this regard, producing a universal vaccine based on virus-like-particles (VLP) could be an ideal approach.  Methods: In this study, the full-length ORF of influenza hemagglutinin (HA) gene from Influenza A virus of H9N2 subtype was amplified by RT-PCR using specific primers to produce HA cDNA. The amplicon was cloned firstly into a T/A cloning vector and then was subcloned into a pFastBacDual donor plasmid through SalI/HindIII restriction sites.  The recombinant HA-pFastBacDual vector was transferred to Escherichia coli DH10Bac cells, to insert the HA gene into the bacmid DNA via a site-specific transposition process. The recombinant bacmid was then extracted and further analyzed by PCR.  Results: Our data indicated that the HA-containing recombinant bacmid was constructed successfully using the transposition mechanism between pFastBacDual-HA and the bacmid. Conclusion: The recombinant baculovirus construct in this work had proper characteristics to be used in production of H9N2 VLP in Sf9 insect cell line in the future studies.