Infectious bursal disease virus (IBDV) is a bi-segmented, dsRNA virus of the Birnaviridae family. The nonstructural protein VP5 has been re- ported to be associated with virus-induced cell apoptosis and pathogenicity, but its role in viral rep- lication has not been unequivocally identified. Based on a PCR introduced mutagenesis strategy, the 33 bp of 96―129 bp located between ORF A1and ORF A2 of genomic segment A of IBDV strain HZ2 were de- leted, and an Nhe I (GcTaGc) site was inserted at 96―102 bp simultaneously. The mutated segment A was ligated into pCI, resulting in pCI-ANhe3. A chi- meric and deficient IBDV strain, named strain ANhe3, was recovered from chicken embryo fibroblast (CEF) cells by co-transfection with pCI-ANhe3 and pCI-mB, derived from the genomic segment B strain HZ2. The indirect fluorescent assay identified that strain ANhe3 could replicate on CEF cells without expression of VP5. Further examination showed that the patho- genesis of strain ANhe3 replicating on SPF chicken embryos was attenuated compared to strain HZ2. This paper provides a new rapid rescue strategy for gene-deleted virus. This strategy lays a basis for gene-deleted vaccine of IBDV.
