Abstract: 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.

Key words: infectious bursal disease virus; VP4; colloidal gold strip