A Novel Time-resolved Fluorescence Immunochromatographic Strip for the Diagnosis of Avian Infectious Bronchitis Virus.

Avian infectious bronchitis virus (AIBV) is the main pathogen of avian infectious bronchitis (AIB), causing significant economic losses in the poultry industry worldwide. A novel time-resolved fluorescence immunochromatographic (TRFIM) strip for the diagnosis of AIB was developed via sensitive and quantitative detection of AIBV antigen. In this study, a two-steps TRFIM strip based on europiumion (Eu) fluorescence microspheres was first developed for sensitive and quantitative detection of AIBV antigen. The AIBV-MAb usage, T line MAb concentration, Eu-AIBV-MAb complex usage and reaction time were optimized to improve the detection performance and improve the on-site detection efficiency. Finally, prepared and assembled the strips according to the optimal conditions, and then evaluate their sensitivity, specificity, precision, stability, and real sample detection performance. A two-steps TRFIM strips were prepared and assembled, and their sensitivity was 0.17 ng/mL, with high specificity for AIBV. The reference interval of the TRFIM strips is > 0.42 ng/mL, the recoveries of the intra-batch and inter-batch samples ranged from 88.50 to 97.35%, and all coefficient of variations (CVs) were less than 10%. The period of validity is more than 12 month at room temperature. The performance of the TRFIM strips in real sample detection is comparable to RT-PCR. Therefore, the developed strips have high sensitivity, accuracy, specificity and stability for detection of chicken AIBV antigen, exhibiting potential for broad applications in the on-site surveillance of AIBV in the poultry industry.