A Novel Peptide-Based Enzyme-Linked Immunosorbent Assay (ELISA) for Detection of Neutralizing Antibodies Against NADC30-like PRRSV GP5 Protein

Porcine reproductive and respiratory syndrome (PRRS) is a pig respiratory disease threating the global swine industry. To combat PRRS, it is necessary of the effective diagnostic detection of antibody, including developing a neutralizing antibody against porcine reproductive and respiratory syndrome virus (PRRSV), especially the currently prevalent NADC30-like PRRSV in China. In this study, we prepared three monoclonal antibodies (mAbs) against NADC30-like PRRSV glycoprotein 5 (GP5) protein, and identified two corresponding precise epitopes (155WR156 and 196QWGRP200). In the neutralization test, 196QWGRP200 recognizing GP5 mAbs (11E6 and 12D1) exhibited obvious neutralizing activity, whereas the 155WR156 recognizing mAb (3A8) showed low neutralizing activity. Based on the two antigenic peptides, a peptide-based Enzyme-Linked Immunosorbent Assay (ELISA) was developed to detect antibodies against PRRSV, presenting high specificity, sensitivity, and repeatability. The concordance rate of the peptide-based ELISA and commercial IDEXX PRRSV X3 Ab ELISA in detection of 81 clinical samples was 82.7%. In conclusion, the GP5 peptide-based ELISA can be used for the detection of neutralizing antibodies against NADC30-like PRRSV, providing a rapid and reliable method for monitoring PRRSV infection.