Recombinant Fowlpox Virus Expressing HA From Subtype H9N2 of Avian Influenza Virus and Its Protective Immunity Against Homologous Challenge in Chickens
表达H9亚型禽流感病毒血凝素基因的重组鸡痘病毒及其免疫效力

The hemagglutinin (HA) gene from the AIV,A/Chicken/China/F/1998(H9N2),was amplified with the RT PCR technique and directionally inserted into transferring vector 1175,resulted in recombinant transferring vector 1175HA.In order to generate recombinant fowlpox virus expressing HA(rFPV HA),the recombinant transferring vector 1175HA was used to transfect the chicken embryo fibroblasts(CEF)pre infected with wide type fowlpox virus.Then,by selection of blue plaques on the CEF overlaid with agar containing X gal,rFPV HA was obtained and purified.The expression of HA by rFPV HA was detected in the recombinant virus infected CEF by indirect immunofluorescence.Experiments on chickens demonstrated that rFPV HA could induce detectable HI antibodies 7 days post vaccination and those HI antibodies of relatively high titers could persist 55 days.rFPV HA also had the same protective efficacies to suppress SPF chickens or commercial broiler chickens with antibodies against FPV from shedding challenged virus from intestine as inactivated vaccine in oil emulsion.