Establishment and preliminary application of an indirect ELISA based on S1 protein of porcine epidemic diarrhea virus

ABSTRACT

The recombinant expression plasmid pIRES-S1 was constructed according to the gene sequence of PEDV S1 in NCBI (GenBankJQ517274). The plasmid pIRES-S1 was transfected into ST cells by electrotransfer. After G418 pressurization screening, western-blot detection and suspension domestication, a stable transduction cell pool expressing S1 protein was obtained. The results of Western-blot showed that S1 protein have good reactivity. An indirect ELISA was established by using S1 protein as coating antigen, and the ELISA was used to detect PEDV clinical serum and PEDV negative serum of imported breeder pigs. Take the serum neutralization test as the standard, the results showed that the sensitivity of the ELISA was 96.3% and the specificity was 97.7%.It was significantly consistent with the serum neutralization test (kappa value=0.882, P < 0.05). The ELISA was used to detect the tracking serum of PEDV back-feeding pigs. The results showed that it could accurately evaluate the growth and decline of PEDV Ig G antibody level in infected pigs. Our results suggested that the ELISA based on S1 protein established in this study has high sensitivity and specificity. It could be used to detect PEDV antibody in clinical serum samples and provide an effective basis for immune evaluation of PEDV in pigs.