Vaccination with E. coli recombinant empty viral particles of infectious bursal disease virus (IBDV) confer protection.

The A genome segment of the highly virulent Infectious bursal disease virus (IBDV) was amplified using long and accurate-RT-PCR (LA-RT-PCR). The entire sequence region encoding VP2, VP4, and VP3 in that order was cloned and sequenced. Following subcloning into the Escherichia coli expression vector pET21a under the T7 promoter, viral proteins were expressed and processed as demonstrated by Western blot analysis. Virus-like particles could be visualized by immuno-electron microscopy in IPTG-induced cells suggesting that viral assembly can take place in E. coli. Induction of anti-IBDV antibodies was detected in chickens immunized with purified recombinant IBDV by intra muscular (i.m.) injection. Furthermore, the vaccinated chickens were protected when challenged with the Gep 5 isolate of IBDV.