A chemiluminescence immunoassay for detecting neutralizing antibodies of foot-and-mouth disease virus serotype A.

Foot-and-mouth disease (FMD) is a highly contagious viral disease affecting cloven-hoofed animals, posing significant threats to global livestock industries. Post-vaccination neutralizing antibody levels reflect vaccine efficacy, but traditional virus neutralization tests (VNT) for detecting neutralizing antibodies requires restrictive biocontainment facilities to handle live virus, is time-consuming and laborious. In this study, we successfully established a high-efficiency magnetic particle-based chemiluminescence immunoassay (MP-CLIA) using two previously characterized monoclonal antibodies (W125 and W145) generated through single B cell antibody technology. The MP-CLIA method exhibited a sensitivity of 95.93% and specificity of 100%, with a cut-off value of 41.395 activity units (U) by detecting the known 221 positive and 122 negative sera. The positive/negative coincidence rate between the MP-CLIA and VNT was 92.2% and the kappa coefficient was 78.19%, indicating a relatively high level of consistency. When integrated with a fully automated chemiluminescence immunoassay analyzer, this method only takes 20 min for a single test. These results show that MP-CLIA is a promising tool for the safe, rapid, and fully automatic detection of neutralizing antibodies against FMD virus (FMDV) serotype A. KEY POINTS: A MP-CLIA using two bovine single B cell antibodies was established. The MP-CLIA method exhibited a sensitivity of 95.93% and specificity of 100%. The MP-CLIA specifically detects neutralizing antibodies against FMDV serotype A.