Chimeras in noncoding regions between serotypes I and II of segment A of infectious bursal disease virus are viable and show pathogenic phenotype in chickens
A. Schroder et al., Chimeras in noncoding regions between serotypes I and II of segment A of infectious bursal disease virus are viable and show pathogenic phenotype in chickens, J GEN VIROL, 81, 2000, pp. 533-540
Two serotypes, I and II, have been identified for infectious bursal disease
virus (IBDV), a member of the family Birnaviridae. Here, the generation by
reverse genetics of IBDV chimeras in segment A of the bisegmented genome i
s reported. The 5- and 3'-noncoding regions (NCRs) of a serotype II strain
were exchanged with the NCRs of a full-length cDNA clone of segment A of a
serotype I strain. Isolated chimeric viruses were characterized in cell cul
ture and susceptible chickens. The results show that IBDV chimeras in segme
nt A were able to replicate in cell culture and that VP1 encoded by a serot
ype I segment B is functionally active with serotype I NCRs as well as with
serotype II NCRs. Chimeric viruses infected susceptible chickens and cause
d mild depletion of bursal cells. Thus, the noncoding regions of segment A
are not responsible for the different pathotypes of IBDV serotypes I and II
.