Development of an indirect ELISA using a novel linear epitope at the C-terminal region of the VP2 protein to specifically detect antibodies against Senecavirus A

Background: Senecavirus A (SVA) is a pathogen that has recently caused porcine idiopathic vesicular disease (PIVD). The clinical signs are similar to those of foot-and-mouth disease, porcine vesicular disease, and vesicular stomatitis. Therefore, identification of SVA as a cause of PIVD is important to eliminate this emerging pathogen.

Methods: In this study, an indirect ELISA based on the VP2 epitope (VP2-epitp-ELISA) was developed to detect antibodies directed against SVA.

Results: A novel linear epitope (²⁷¹GLRNRFTTGTDEEQ²⁸⁴) was first identified at the C-terminus of the VP2 protein by epitope mapping. The diagnostic performance of VP2-epitp-ELISA was estimated by testing a panel of known background sera from swine. Under the optimum test conditions, when the cutoff value was 37%, the diagnostic sensitivity (Dn) and diagnostic specificity (Dp) of the assay were 91.13% and 91.17%, respectively. The accuracy of VP2-epitp-ELISA was validated and further compared with that of commercial diagnostic kits. The diagnostic results showed that VP2-epitp-ELISA did not cross-react with serum positive for other idiopathic vesicular diseases and had a concordance rate of 90.41% with the Swinecheck^® SVA bELISA.

Conclusions: These results indicate that VP2-epitp-ELISA is suitable for specific detection of antibodies against SVA in swine.