Objective  A method for detecting SIgA antibodies of porcine epidemic diarrhea virus (PEDV) was established.

  Methods  Using a purified PEDV ZJ08 strain as coating antigen and the antibody for secretory component(SC) labeled by horseradish peroxidase (HRP) as secondary antibody, an indirect ELISA assay with optimized conditions was developed to detect the specific SIgA antibody of PEDV.

  Result  The optimized assay applied a working antigen concentration of 0.6 μg per well, a 1∶5 sample dilution, a coating at 37 ℃ for 1 h, and an 100× dilution of the labeled antibody for 1.5 h incubation at 37 ℃. Other than the target detection, the assay did not react with porcine rotavirus or transmissible gastroenteritis virus. The inter- or intra-batch variations of the assay on test results were less than 10%. On the milk from vaccinated pigs, a 98.1% positive detection on IgA, which was significantly higher than 69.2% on SIgA and merely 70.6% on combined IgA and SIgA, was achieved indicating the deficiency of a single IgA test for an accurate determination on the mucosal immunity of the animal.

  Conclusion  The established assay appeared to appropriately reveal the specific SIgA antibody produced in pigs for protection of the livestock from PEDV by the vaccination.