Construction and characterization of reverse genetic system for H9N2 avian influenza.

Objective To provide a technology platform for vaccine development as well as the research on transmission and pathogenesis, the reverse genetic system for H9N2 avian influenza virus was established. Methods Eight full-length cDNAs of avian influenza virus A/Guangzhou/333/99(HgN2)were amplified by RT-PCR and separately cloned into the transcription/expression vector, pCI-poll. The 8 plasmids DNA was co-transfected into 293T cell, the cell supernatant was collected and inoculated into embryonated eggs, the rescued virus from the allantoic fluid was identified by hemagglutinination assay. Results The avian influenza HgN2 virus was successfully rescued by 8 plasmids co-transfection in 293T cells. The hemagglutinination titer of the rescued virus is up to 29/50 μl and its growth curve remained relatively as to the wild-type virus.Conclusion The reverse genetic for avian influenza H9N2 subtype virus has been established successfully.