Neutralizing monoclonal antibody sandwich liquid-phase blocking enzyme-linked immunosorbent assay for detection of Foot-and-mouth disease virus type O antibodies.

Liquid-phase blocking enzyme-linked immunosorbent assay (LPBE) using the neutralizing monoclonal antibody (mAb) sandwich method (M-LPBE) for detection of Foot-and-mouth disease virus (FMDV) type O antibodies was developed. Two neutralizing mAbs, 72C1 and 65H6, were raised against the FMDV O/JPN/2000 strain, and used as trapping and peroxidase-labeled detecting antibodies, respectively. Sera from animals experimentally infected with FMDV showed specific positive results by M-LPBE, which were correlated with the results of the virus neutralization test (VNT). When 303 negative bovine and 302 negative swine sera were tested, the specificity of M-LPBE was 100% and 99.7%, respectively. In addition, nine samples that had been collected in 2000 in Japan and regarded as evidently false positives by LPBE (supplied by the World Reference Laboratory for Foot-and-Mouth Disease) were uniformly negative by M-LPBE, just like VNT. Therefore, M-LPBE seems to have sufficient specificity for FMDV type O antibody screening and diagnosis.