Attenuation of a Highly Virulent Strain SD0210 of Infectious Bursal Disease Virus
Abstract: A very virulent strain SD0210 of Infectious bursal disease virus (vvIBDV) was adapted to chicken embryo fibroblast cell (CEF) after propagating in SPF chicken embryo for 10 generations and CEF for 18 generations. The test of pathogenicity, virulent stability and immunogenicity in chickens showed that the cell-adapted virus kept the immunogenicity of paternal virus, while its virulence did not reverse. The change pattern of deduced amino acid sequences in VP2 hypervariable region during the adaptation to CEF and transform from high pathogenicity to low pathogenicity has been obtained. When the virus was passed to the 18th generation, it began to adapt CEF and cause cell pathological effect (CPE). To 21th generation, the virus still kept its paternal immunogenicity and had no pathogenicity to SPF chickens even it was propagated to 15th generation in SPF chicken bodies.