Affinity-based selection of anti-Feline Leukaemia Virus p27 monoclonal antibodies for efficient lateral flow assay development.

Traditional diagnostic methods like RT-PCR and proviral DNA PCR have limitations, underscoring the need for swift, sensitive alternatives such as lateral flow immunoassays (LFIA). Yet, efficiently identifying monoclonal antibody (mAb) pairs for robust ternary antigen-antibody interactions remains a universal bottleneck, as conventional ELISA screening is costly and may not accurately reflect native binding. Here, we combined ELISA with Spectral Shift Technology (SST) to minimise reagent use and comprehensively profile anti-FeLV p27 mAbs. This orthogonal approach enabled rapid selection of two low nanomolar mAbs with different epitope targets that form a ternary complex, which translates into a sensitive detection of the FeLV p27 in a LFIA prototype. Our screening methodology supports resource-efficient LFIA development for FeLV and extends to other significant animal and human pathogens like Monkeypox or Helicobacter pylori, improving diagnostics and quality control.