Abstract

Background Porcine epidemic diarrhoea virus (PEDV) causes substantial financial losses on pig farming worldwide. Monitoring PEDV-specific IgA antibodies is essential for assessing vaccine efficacy. In this study, we developed a fully automated chemiluminescence immunoassay (CLIA) for the detection of PEDV IgA antibodies in both serum and milk. Results This S1-CLIA utilizes recombinant S1 protein-coated magnetic particles (S1-MPs) for antibody capture and an acridinium ester-labeled mouse anti-pig IgA monoclonal antibody (mpIgA-AE) to generate chemiluminescence signals. Under optimized conditions, S1-CLIA achieved a diagnostic sensitivity of 96.30% and specificity of 98.48%, with a cut-off index of 1.0. S1-CLIA exhibited excellent repeatability (coefficient of variation < 10%) and no cross-reactivity with sera positive for other common swine pathogens. Compared to a commercial enzyme-linked immunosorbent assay (ELISA), S1-CLIA achieved 93.93% agreement rate, but offered a significantly broader dynamic range (35.48-fold). Notably, S1-CLIA results correlated well with virus neutralization titers (VNT), yielding R² values of 0.6660 (serum) and 0.7639 (milk). Conclusions With capability of fully automated testing, this novel S1-CLIA presents a robust platform for large-scale evaluation of PEDV immunity.