Development of an indirect ELISA for the detection of Bovine coronavirus using recombinant N protein

An indirect ELISA was established for the rapid detection of specific bovine coronavirus(BCV) antibodies in cattle using a recombinant N protein as an antigen.The recombinant N protein was expressed from recombinant plasmid pET30a-N in Escherichia coli.Western blot confirmed that the expressed fusion protein could specifically react with antiserum against BCV.This assay was optimized using 1.75 μg/mL N protein as coat antigen,1∶200 dilution of testing serum and 1∶8 000 dilution of HRP-labeled goat anti-bovine IgG.Test against 256 serum samples from Heilongjiang province by this assay detected 65.23 % positive,which showed 95.31 % agreement with VN test.