Recombinant fowlpox viruses(rFPVs)coexpressing MDV gB and chicken type Ⅱ interferon (IFN-Ⅱ) gene were constructed by using different promoters of Ps and PE/L.rFPVs were selected and purified by blue plaque expressing β-galactosidase.The expression of MDV gB gene was confirmed by indirect immunofluorescence assay.The levels of MDV gB expressed in rFPV-gB-IFN under the control of the synthetic promoter Ps was same as that in rFPV-gB.The expression of IFN-Ⅱ was examined in chicken embryo fibroblast(CEF) by protection against vesicular stomatitis virus-induced cytopathic effect.The levels of IFN expressed in CEF was 640～1280 units/mL.When rFPVs were propagated in CEF,the plaque sizes of rFPV-gB were larger than those of rFPV-gB-IFN,the plaque formation units of rFPV-gB were also more than those of rFPV-gB-IFN.
