Development and application of a novel multi-peptide indirect ELISA based on VP1/VP2/VP3 proteins for the antibody...

The newly emerged senecavirus A (SVA) has been identified as an important etiological agent of vesicular disease in pigs, posing a major threat to the global swine industry. The absence of licensed vaccines in China against SVA underscores the urgent need for reliable diagnostic tools to control SVA infections. In this study, twelve immunodominant peptides were screened from the VP1, VP2, and VP3 proteins of SVA. Subsequently, a multi-peptide fusion protein VP123 expressed in Escherichia coli was used to develop an indirect ELISA (iELISA) for SVA antibodies detection. This assay showed no cross-reactivity with serum antibodies against other common swine viruses, and exhibited remarkable reproducibility and stability. ROC analysis revealed AUC values of 0.955 (vs. IFA) and 0.973 (vs. VNT), with strong correlation to VNT (Spearman's R = 0.6998). When the iELISA was employed to detect SVA seroprevalence in large-scale pig farms in Shanxi Province, China, the results revealed that SVA was widely circulating in pig farms, with a positive rate of 81.95%. In conclusion, the novel iELISA features strong stability, specificity, and sensitivity. It holds great promise as a diagnostic tool for SVA infections and for monitoring antibody responses in pigs vaccinated with SVA vaccines.