Development of recombinant VP2 vaccine for the prevention of infectious bursal disease of chickens.

The objective of the present study was to investigate the feasibility of a subunit vaccine and a live bacteria vaccine to protect chickens against infectious bursal disease virus (IBDV) infection. The gene for VP2 of a new wild-type very virulent IBDV (vvIBDV) strain was cloned into an Escherichia coli expression system. Following expression, the recombinant VP2 and the induced expression bacteria were used to vaccinate chickens against virulent IBDV (vIBDV). Three weeks after the vaccination, chickens were inoculated with IBDV strain BC 6/85 by intranasal route or eyedrop route, prior to challenge anti-IBDV serum antibody was detected by AGP. All chickens vaccinated with recombinant VP2 could be detected anti-IBDV antibody. The subunit vaccine of recombinant VP2 conferred protection for 90--100% chickens, live bacteria vaccine of recombinant VP2 conferred protection for 85.7% chickens. The results indicate that E. coli BL 21/pET 28 a-VP2 could be used to develop recombinant VP2 vaccine against infectious bursal disease in chickens.