A quantum dots dual immunochromatography strip for differential detection of high and low virulence ASFV antibodies.

UNLABELLED: African swine fever (ASF), caused by African swine fever virus (ASFV), is a highly contagious disease that infects both domestic and wild pigs and poses a significant threat to the global pig industry. Given the absence of vaccines and effective treatments, the development of rapid and precise serological diagnostic methods is critical for the prevention and control of ASFV. However, traditional enzyme-linked immunosorbent assay (ELISA) is unsuitable for point-of-care testing (POCT). Immunochromatographic strip (ICS) offers portability but suffers from low sensitivity and an inability to differentiate between high virulence wild-type ASFV and low virulence ASFVΔCD2v infections. Consequently, there is an urgent need to develop a rapid, sensitive, and accurate ICS that can distinguish between wild-type ASFV and ASFVΔCD2v infection for ASFV control. In this study, we developed a novel quantum dot (QDs) dual ICS using p54 and CD2v proteins as test 1 line (T1 line) and test 2 line (T2 line) capture antigens, and QDs as the tracer for specific ASFV antibody detection. The QDs dual ICS had no cross-reactivity with other swine disease antibodies, could detect ASFV antibody-positive serum diluted to 1:106, and exhibited excellent repeatability, reproducibility, and stability. A total of 589 clinical samples were analyzed using QDs dual ICS. Compared to commercial ELISA kits, T1 line achieved 99.66% accuracy, 100% sensitivity, and 99.62% specificity, and T2 line achieved 100% accuracy, sensitivity, and specificity. It offers a new technical method for POCT of ASFV antibodies and differentiation between wild-type ASFV and ASFVΔCD2v infection.

IMPORTANCE

The concurrent prevalence of both high-virulence wild-type ASFV and low-virulence ASFVΔCD2v has increased the pressure on the prevention and control of ASFV. Based on the p54 and CD2v proteins of ASFV, a highly sensitive and specific quantum dots (QDs) dual immunochromatography strip (ICS) was developed using QDs conjugated with SPA as a tracer. The developed novel QDs dual ICS can rapidly detect ASFV antibodies and differentiate from high-virulence wild-type ASFV or low-virulence ASFVΔCD2v infections. This novel QDs dual ICS could be used for the serological differential diagnosis and epidemiology study of ASFV.