Fluorescence-activated cell sorting-based efficient screening of monensin monoclonal antibodies and applications in...

Monensin is widely used in livestock and poultry for disease prevention and growth promotion. Still, its improper use can lead to residues in animal-derived foods, posing risks to human health. In immunoassays, monoclonal antibodies (mAbs) remain a preferred choice due to their high sensitivity and specificity. However, traditional hybridoma technology often suffers from a lengthy screening cycle and the risk of losing effective clones. To address these limitations, this study employed fluorescently labeled monensin antigens combined with fluorescence-activated cell sorting (FACS) for rapid screening of hybridoma cells secreting anti-monensin mAbs. Compared to the conventional limiting dilution method, this approach increased the yield of specific hybridoma cells by tenfold and reduced the screening cycle from four weeks to one week. Based on the selected mAb (4E6), a rapid visual lateral flow immunoassay (LFIA) was developed for on-site detection of monensin, with a total detection time of 10 min. The assay exhibited a half-maximal inhibitory concentration (IC₅₀) of 2.32 μg/kg and a linear detection range of 0.32-10.3 μg/kg. This study provides a promising strategy for efficient hybridoma cell screening and practical monitoring of monensin residues in environmental and food samples.