Construction of recombinant fowlpox virus coexpressing HA from subtype H5 of avain influenza virus and chicken interleukin-18

Abstract:

[Objective] We developed recombinant fowlpox viruses (rFPV) coexpressing chicken IL-18 and H5 AIV HA. [Methods] Recombinant expression plasmid pSYHA/IL-18 was constructed by cloning chicken IL-18 into transfer plasmid containing HA gene and transfected by lipofectamine on the chicken embryo fibroblasts cell (CEF) pre-infected with S-FPV-017. By selecting blue plaques on the CEF overlaid with agar containing X-gal, recombinants fowlpox virus rFPV-HA-IL-18 were obtained, and identified by PCR. [Results]The recombinant fowlpox viruses contained chicken IL-18 and HA gene and had stable genetic properties. The expression of HA was detected in the recombinant virus-infected CEF by indirect immunofluorescence using antibody against AIV. The expression of chicken IL-18 was detected by MTT in the recombinant virus-infected CEF fluid. The chickens vaccinated with recombinant fowlpox virus rFPV-HA-IL-18 and rFPV-HA had detectable hemagglutination inhibition (HI) antibody at 7 days post-vaccination, and HI antibody titers rose to peak at 14 days post-vaccination. No HI antibody was detected in the control or fowlpox virus immunized chickens before or after immunization. The chickens vaccinated with rFPV-HA-IL-18 had higher HI antibody titers than the chickens vaccinated with rFPV-HA. [Conclusion] Development of recombinant fowlpox virus (rFPV- HA-IL-18) had strong biological activity.