Optimization and application of an immuoperoxidase monolayer assay for the detection of PRRSV.

Background: Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), is a highly contagious disease with high morbidity and mortality that affects the global swine industry. Despite efforts to control it, there is still a widespread dissemination of PRRSV with obvious genetic variations in swine population, resulting in huge economic losses annually. Consequently, accurate laboratory diagnosis is crucial for the rapid confirmation of PRRSV infections.

Results: An immunoperoxidase monolayer assay (IPMA) was developed for the specific and sensitive detection of PRRSV based on a broad-spectrum anti-PRRSV monoclonal antibody (mAb) 28F6. The mAb 28F6-based IPMA could specifically detect PRRSV and possessed no cross-reactions with CSFV, PCV2, and PEDV. Sensitivity analysis showed that the limit of detection of the IPMA reached 10^- 2.25 TCID₅₀/100 µL. There was no significant difference in the detection of PRRSV of different passages with different batches of mAb 28F6, indicating that the IPMA had excellent repeatability. Additionally, the IPMA was capable of detecting multiple PRRSV variants, including field strains (e.g., BJ-4, HN07-1, and HNhx) and vaccine strains (e.g., HuN4-F112, JXA1-R, TJM-F92, GDr180, VR2332, CH-1R, and R98). Validation of the IPMA with qRT-PCR showed 100% concordance between the two assays for detecting PRRSV from 108 clinical samples.

Conclusions: The IPMA could meet the demand for the specific and sensitive detection of PRRSV, which is helpful for accurate monitoring and early warning of PRRSV infections.