Study and Application on an Immunochromatographic Method for Detection the VP4 Protein Antibody of Infectious Bursal Disease Virus

The VP4 gene was acquired by RT-PCR from Binzhou isolate of infectious bursal disease virus,the VP4 expression plasmid was constructed by inserting the target fragment into pGEX-4T-1 vectors.The expression VP4 proteins were acquired by inducing and purifying.An immunochromatograpic strip was developed for the detection VP4 protein antibody of infectious bursal disease virus.Rabbit anti-chicken IgG was labled with colloidal gold as a detection reagent,and recombinant VP4 protein of IBDV was blotted on the test line while goat anti-rabbit IgG was used on the control line of the nitrocellulose membrane.The results of specificity showed that the strip was positive in the detection of reference sera against IBDV BC6/85 virulent and negative to the detection of standard positive serum of Newcastle disease virus,anvian influenza virus H5 and H9 subtypes,infectious bronchitis virus were negative,0.85% isotonic Na chloride,reference sera against IBDV BC6/85 virulent.Compared with ELISA,the sensitivity of the gold-immunochromatographic assay(GICA) was low two titer.The agreement rate between the two tests was 99.38%.The detection time of VP4 IgG against IBDV by the GICA was less than 10 min.The GICA test strip was a reliable and useful tool for the on-site surveillance of IBDV.