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Development of a chemiluminescence immunoassay using recombinant non‐structural epitope‐based proteins to accurately differentiate foot‐and‐mouth disease virus‐infected and vaccinated bovines

Liu, Z.‐Z., Zhao, F.‐R., Gao, S.‐D., Shao, J.‐J., Zhang, Y.‐G., Chang, H.‐Y.
Transboundary and emerging diseases 2018 v.65 no.2 pp. 338-344
Foot-and-mouth disease virus, blood serum, cattle, chemiluminescence immunoassays, diagnostic sensitivity, diagnostic specificity, emerging diseases, enzyme-linked immunosorbent assay, foot-and-mouth disease, inactivated vaccines, viral nonstructural proteins
The contamination of inactivated vaccine with non‐structural proteins (NSPs) leads to a high false‐positive rate, which is a substantial barrier to accurately differentiate foot‐and‐mouth disease virus (FMDV)‐infected animals from vaccinated animals. To address this problem, a new chemiluminescence immunoassay (CLIA) method was developed to detect antibodies targeting the two recombinant epitope‐based proteins located in 3A and 3B. The 3Aepitp‐3Bepitp CLIA exhibited a diagnostic sensitivity of 94.0% and a diagnostic specificity of 97.5% for the detection of serum samples (naïve bovines, n = 52, vaccinated bovines, n = 422, infected bovines, n = 116) from animals with known status. The CLIA method also had a concordance rate of 88.1% with the PrioCHECK FMDV NSP ELISA based on the detection of 270 serum samples from the field. Importantly, the 3Aepitp‐3Bepitp CLIA produced no false‐positives when used to detect FMDV in samples from bovines that had been vaccinated up to five times, and it was demonstrated a low false‐positive rate when the bovines had been vaccinated up to ten (2.15%) and fifteen times (5.93%). Therefore, the 3Aepitp‐3Bepitp CLIA detects FMDV in samples from frequently vaccinated bovines with high accuracy and represents an alternative method to differentiate FMDV‐infected and vaccinated bovines.