A VP5- IBDV mutant was replication competent in cell culture, exhibiting a delay in replication compared to the VP5+ parental virus but achieving similar final yields.
Is the VP5 protein essential for the replication of Infectious bursal disease virus in cell culture?
The VP5 protein is not essential for IBDV replication in cell culture, suggesting it could be a target for developing deleted, marked vaccines.
Infectious bursal disease virus (IBDV), a member of the Birnaviridae family, encodes in its bisegmented double-stranded RNA genome four structural virion proteins, VP1, VP2, VP3, and VP4, as well as a nonstructural protein, VP5. Recently, the establishment of an infectious cRNA system for IBDV has been described (E. Mundt and V. N. Vakharia, Proc. Natl. Acad. Sci. USA 93:11131-11136, 1996). Here, we report the isolation of a VP5- IBDV mutant constructed by site-directed mutagenesis of the methionine start codon of VP5, followed by cRNA transfection. The resulting virus mutant was replication competent in cell culture, which indicates that VP5 is not required for productive replication of IBDV. Absence of VP5 expression was verified by lack of reactivity with newly established anti-VP5 monoclonal antibodies and polyclonal sera. VP5- IBDV exhibited a delay in replication in chicken embryo cells compared to the VP5+ parental virus. However, final yields were similar. Our results thus show that VP5 is nonessential for IBDV replication, which makes it a prime candidate for the construction of deleted, marked vaccines.
Mundt et al. (Tue,) conducted a other in Infectious bursal disease virus (IBDV) infection. VP5- IBDV mutant vs. VP5+ parental virus was evaluated on Viral replication in cell culture. A VP5- IBDV mutant was replication competent in cell culture, exhibiting a delay in replication compared to the VP5+ parental virus but achieving similar final yields.