Rapid detection of African swine fever virus by a blue latex microsphere immunochromatographic strip.

Abstract

African swine fever (ASF) is a contagious viral disease in pigs, caused by the African swine fever virus (ASFV). Currently, there are no effective vaccines and drugs for ASFV, making diagnostic methods crucial for the prevention and control of ASF. In this study, the ASFV p30 protein was successfully expressed using a prokaryotic expression system and used as an immunogen to prepare monoclonal antibody (mAb) 2A5. The antigenic epitope recognized by the mAb 2A5 was identified as ⁵⁸VKYDIVKSARIYAGQGY⁷⁴. Then, a blue latex microsphere immunochromatographic strip method for detecting ASFV antigens was established. Wherein a rabbit polyclonal antibody (pAb) against p30 stored in our laboratory was coupled with blue latex microspheres to prepare an immune probe, with mAb 2A5 as the test line and goat anti-rabbit IgG as the control line. The immunochromatographic strip exhibited excellent sensitivity, with a minimum detection limit of 10 ng/mL for the p30 protein. It demonstrated good specificity, showing no cross-reactivity with PRRSV, PCV2, PPV, and PEDV. Moreover, it maintained good stability and could be stored for at least 100 days at 37 °C. The concordance rate between the immunochromatographic strip and qPCR test kit was 92.2%. The immunochromatographic strip method can meet the requirements of clinical testing and provide technical support for ASFV diagnosis.