Establishment of an Indirect ELISA Method for Porcine Eepidemic Diarrhea Virus S Protein

PurposeTo establish a rapid and accurate method for the detection of Porcine epidemic diarrhea virus (PEDV).

MethodWe established an efficient and specific indirect ELISA method based on the PEDV S protein. The PEDV S gene was amplified by PCR and designated as SJ. After purification and identification, it was cloned into the expression vector pET-32a (+) to construct the recombinant plasmid pET-32a (+)-SJ. After the recombinant protein was induced, purified and identified, the protein concentration was determined. Then the antigen was coated on the plate to optimize the ELISA reaction conditions. At last, specificity, repeatability, conformity and clinical application of the established method were evaluated.

ResultsThe S protein expressed in prokaryotes was about 35 ku, and the concentration was 1.145 mg/mL. It was identified by Western-blot as having good reactivity. The PEDV indirect ELISA method used S protein as the coated antigen and only detected positive PEDV serum, showing good specificity. The variation coefficients of both intra-batch and inter-batch repeatability tests were less than 6%. The coincidence rate between the test results of clinical samples and the commercial test results was 96.67%.

ConclusionThis method has good specificity, high repeatability and low cost, and can be used for clinical PEDV serum antibody detection and PEDV epidemiological monitoring, which is of great significance for the prevention of this disease.