Development of an indirect ELISA based on a truncated S protein of the porcine epidemic diarrhea virus

作者:Li, Yufeng*; Zheng, Fangyuan; Fan, Baochao; Muhammad, Hassan Mushtaq; Zou, Yao; Jiang, Ping
来源:Canadian Journal of Microbiology, 2015, 61(11): 811-817.
DOI:10.1139/cjm-2015-0213

摘要

Porcine epidemic diarrhea (PED) is a highly contagious, enteric disease of swine caused by the porcine epidemic diarrhea virus (PEDV). To find a suitable ELISA method to assess the infection of PEDV and the effectiveness of vaccines, we developed and evaluated an indirect enzyme-linked immunosorbent assay (iELISA) based on a truncated recombinant spike (S) protein expressed in Escherichia coli. The parameters of the iELISA were optimized, and the cutoff value determined as 0.259 by analyzing optical density (OD) values of 80 PEDV negative sera confirmed by western blot. Repeatability tests revealed that the coefficients of variation of positive sera within and between runs were both less than 10%. Cross-reactivity assays demonstrated that iELISA was PEDV-specific. A virus neutralization test with sera of 7 different OD values showed a positive correlation between the OD values and virus neutralization. The results suggest this iELISA is specific, sensitive, and repeatable. Further studies should focus on the relationship between OD values of sera and its virus neutralization.