Abstract: Abstract: The S1, N and M genes of IBVSX16 strain were sub-cloned into the eukaryotic expression plasmid pVAX1, which is driven by CMV promoter, named pVAX1-16S1, pVAX1-16N and pVAX1-16M, respectively. Purified plasmids DNA were transfected into BHK-21 cells by lipofectamine. The IBV S1, N and M proteins were expressed in BHK-21, which do specifically react to the CDV antisera. The mice inoculated with these plasmids induced the immune response against IBV.