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Recombinant structural protein VP1 of foot-and-mouth disease virus serotype O was expressed in Escherichia coli and then purified using Nickel affinity chromatography. A chemiluminescent enzyme immunoassay (CLEIA) method was established using the purified recombinant protein as coating antigen to detect antibody of foot-and-mouth disease virus serotype O in swine. The specificity of VP1-CLEIA method is 100%. The coefficients of variation in the plate and between plates are 1.10%-6.70% and 0.66%-4.80%, respectively. Comparing with the commercial indirect ELISA kit or liquid phase block ELISA kit, the calculated coincidence rate is 93.50% or 94.00%. The high specificity and stability suggested this detection method can be used to monitor the antibody level of foot-and-mouth disease virus serotype O in swine.

To establish a sensitive, rapid and simple gold immunochromatography assay (GICA) for detecting Asia1 type of foot-and-mouth disease virus (FMDV) from the field samples. The purified anti-FMDV type Asia1 monoclonal antibody labeled with colloidal gold and the goat anti-Guinea pig IgG were wrapped onto nitrocellulose membrane as the test line (T line) and the control line (C line), respectively. The strip was then further optimized. A total of 87 field samples were detected. The results indicated a correct rate of 98.8% for detecting FMDV Asia1 type. No cross reaction was found with swine vesicular disease (SVD) and FMDV O, A and C type antigen. The sensitivity of the strip can reach to 10(-4) (TCID50 6.25). It had the same results for positive and negative specimens tested in three times. This strip could be stored at 4 degrees C for three months. In this study, the established gold immunochromatographic strip test kit is simple, rapid, sensitive and specific for detecting FMDV type Asial, and is potentially useful for the for pen-side diagnosis.

Aim: To establish a colloid gold-immunochromatography assay (GICA) for detecting type Asia I foot-and-mouth disease virus (FMDV)., Methods: Colloidal gold was obtained by reducing the gold chloride with sodium citrate and then it was coupled with the purified anti-FMDV type Asia I antibody.The purified anti-FMDV type Asia I antibody and the goat anti-Guinea pig IgG were wrapped onto the nitrocellulose membrane as test line (T line) and control line (C line). The GICA strip was assembled with the purified antibody labelled with colloidal gold and the nitrocellulose containing antibody. The sensitivity, specificity and stability of GICA strip were evaluated in the diagnosis of FMD viral antigen from clinical samples., Results: The strip was highly sensitive to FMDV type Asia I(0.116 mg/L) and it had the same result for positive specimens tested thrice. Cross tests proved no cross reaction was found with other serotype FMDV and Swine vesicular disease (SVD) antigen.The corresponding rate of GICA with RIHA was 96.87% for detecting the field sample. The stably test found the strip could be stored for 12 months., Conclusion: The GICA strip is a simple and rapid immunochromatographic test strip for the detection of FMDV type Asia I with high sensitivity and specificity.

The complete gene encoding the structural protein of FMDV(VP1) was subcloned into expression vector pPROex-HT, resulting in the fusion expression plasmid pPROexHT-VP1. After transformed into E. coli BL21(DE3) and induced by IPTG, the fusion protein was expressed in high level. Western blot was performed to confirm that the expressed fusion protein could specifically react with antiserum against FMDV. Based on the fusion protein further purified, a novel indirect ELISA (VP1-ELISA) was developed to detect FMDV antibody in pigs. Comparison between VPl-ELISA and the government standard kit (liquid phase block ELISA) showed the two methods had 96.25 percent agreement by detecting 80 serum samples, indicating that the indirect VP1-ELISA was specific and sensitive.