Preparation and laboratory evaluation of live attenuated Infectious Bursal Disease [IBD] virus vaccine from recent Egyptian isolate propagated on chicken embryo fibroblast [CEF] cell culture.

ABSTRACT

Very virulent IBDV was propagated for 3 passages in SPF-ECE followed by 3 passages in young susceptible chicks then for 3 passages in SPF-ECE then for further 12 passages in SPF-ECE. The first passage of last propagation was further propagated for 3 passages on Vero cells and for 60 passages in CEF-cell culture. The passage 40 of propagated IBDV proved to be safe and highly immunogenic by virus neutralization test. It still elicited high neutralizing antibody titers [18 log2] for a stationary phase about 7 months [the end of the experiment] and high values of lymphocyte blastogenesis [0.560 versus control 0.03]. Vaccinated chicks well protected against challenge with highly virulent IBDV after 3 weeks post-vaccination [PV]. The prepared vaccine has superior potential immunogenic effect than commercial live mild and intermediate plus [hot] vaccines. The vaccine is effective even when preserved for 8 months [the end of experiment] at -20C