Development of a Competitive Chemiluminescent Enzyme Immunoassay Based on Recombinant FMDV VP2 Protein for Rapid and Simultaneous Detection of Antibodies Against Foot-and-Mouth Disease Virus Serotypes O and A.

Timely detection of specific antibodies against foot-and-mouth disease virus (FMDV) is critical to effective prevention and control of the disease. In this study, we developed a competitive chemiluminescent enzyme immunoassay (cCLEIA) based on recombinant FMDV VP2 protein (FMDV-VP2 cCLEIA) for simultaneous detection of antibodies against FMDV serotypes O and A in serum samples. Using a cut-off of 35% percentage inhibition (PI), the FMDV-VP2 cCLEIA achieved a relative sensitivity of 101.5% and a relative specificity of 102% compared with commercial FMDV serotypes O and A liquid-phase blocking ELISA (LPBE) kits. The assay showed high specificity for detection of antibodies against FMDV serotypes A and O, with no cross-reactivity observed against positive sera for classical swine fever virus, porcine reproductive and respiratory syndrome virus, and Senecavirus A. Both intra-batch and inter-batch coefficients of variation were below 15%, confirming excellent assay reproducibility. The testing of 40 field serum samples yielded a positive detection rate of 95% using the FMDV-VP2 cCLEIA, compared with 92.5% using the FMDV serotypes O and A LPBE kits. In conclusion, the FMDV-VP2 cCLEIA developed is a rapid, sensitive assay for simultaneous detection of antibodies against FMDV serotypes O and A, which may offer a valuable tool for foot-and-mouth disease (FMD) surveillance and control programs.