Rapid and sensitive detection of H3 AIV HA1 protein using a quantum dot-labeled immunochromatographic strip

Avian influenza virus (AIV) subtype H3 has evolved into a major zoonotic pathogen and poses a potential threat to public health. Hemagglutinin 1 region (HA1) proteins constitute the globular head region of hemagglutinin proteins, contain receptor-binding domains and esterase structural domains, and are an important molecular basis for antigenic variation in AIV. Therefore, a rapid and highly sensitive assay for the HA1 protein of this viral subtype is essential for effective epidemic control. Using quantum dots (QDs) as the core material, a fast-response fluorescent immunochromatographic test strip was developed in this study for the specific recognition of the HA1 protein. The fluorescent probe required for detection was constructed by covalently binding the QDs to a high-affinity HA1 monoclonal antibody (mAb). The test strip works based on the double antibody sandwich principle and can detect the HA1 protein in as little as 15 min. The method was validated with recombinant HA1 protein and the visual limit of detection (LOD) was 15.63 ng/mL. The assay exhibited high specificity, demonstrating no cross-reactivity with other prevalent subtypes of AIV, infectious bronchitis virus (IBV), or infectious bursal disease virus (IBDV). In conclusion, this method combines high sensitivity, high specificity and high timeliness, which can provide an effective idea for the detection and rapid diagnosis of avian influenza.