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

Abstract

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.

Identification of a linear B-cell epitope on the “puff” loop of the Senecavirus A VP2 protein involved in receptor binding

“…Furthermore, the C-terminal region of VP2 ( 271 GLRNRFTTGTDEEQ 284 ) was identified as a diagnostic target for testing SVA antibodies in pigs (Ma et al, 2022 ). In the present study, the minimal epitope 266 SPYFNGL 272 of the C-terminus of VP2 was identified accurately by the mAb 2C7, and two amino acids (Gly 271 and Leu 272 ) were found overlapping with previous study conducted by Ma et al Recently, the epitope 267 PYFNGLRNRFTTGT 280 was predicted and identified by bioinformatics-based computational prediction and the Pepscan approach (Ru et al, 2023 ).…”

“…In prior studies, several B-cell epitopes (BCEs) of SVA VP2 were identified by bioinformatics prediction (Ru et al, 2023 ; Zhang et al, 2023 ), overlapping synthesis of polypeptides (Ma et al, 2022 ) and monoclonal antibodies (mAbs) (Fan et al, 2020 ; Wen et al, 2022 ). It has been confirmed that 153 QELNEE 158 is a conserved antigenic epitope of the VP2 protein and has virus-neutralizing activity (Wen et al, 2022 ).…”

The Establishment and Application of Indirect 3AB-ELISA for the Detection of Antibodies against Senecavirus A

“…Seroconversion against SVA in clinically affected and non-clinically affected sows at early stages of the outbreak and maternal SVA antibodies in offspring were detected by rVP1 ELISA [17]. Recently, an indirect ELISA based on the VP2 epitope (VP2-epitp-ELISA) was developed to detect antibodies directed against SVA, and no cross-reaction with positive serum antibodies occurred for other idiopathic vesicular diseases [18]. Although these ELISA methods were well characterized, none of them were extended to mass diagnostic programs.…”

“…Nevertheless, few studies have clarified that the antigenic reactivity of SVA VP1 is not the most immunodominant. Recently, an indirect ELISA based on the VP2 epitope (VP2-epitp-ELISA) was developed to detect antibodies directed against SVA [18]. The method has not been utilized to process large numbers of samples in epidemiological surveillance and mass diagnostic programs.…”

Real-time detection of Seneca Valley virus by one-tube RPA-CRISPR/Cas12a assay

“…The symptoms observed in pigs infected by SVA resemble those caused by vesicular stomatitis virus (VSV) and foot-and-mouth disease virus (FMDV), leading to difficulties in clinical differential diagnosis ( Schmitt, 2002 ; Knight-Jones et al., 2016 ). Currently, many methods such as PCR-based assays and ELISA have been established for the laboratory diagnosis of SVA ( Bracht et al., 2016 ; Feronato et al., 2018 ; Mu et al., 2020 ; Ma Z. et al., 2022 ; Yan et al., 2023 ). However, these methods are cumbersome, complex and time-consuming.…”