Screening and validation of rabbit monoclonal antibody pair against human FGF21 for human plasma FGF21 high sensitivity bioanalysis

Summary FGF21 has been reported to have a high correlation with various dysmetabolism-associated diseases. However, a portion of FGF21 in human blood samples remains below the detection limit of the state-of-the-art commercial ELISA kit. Quantitative determination of FGF21 with high sensitivity will benefit FGF21 functional research and drug development. Here, a pair of monoclonal antibodies was screened and prepared through immunizing a rabbit with recombinant human FGF21, flow cytometry single B cell sorting, and ELISA screening. The lowest limit of quantification of the sandwich ELISA method was 1.526 pg/mL, which possessed the highest sensitivity ever reported. Moreover, the carboxyl-terminus 10 amino acids of FGF21 were found to be unnecessary for the binding of this pair of antibodies. The sandwich ELISA method exhibited good robustness when validated using 22 human plasma samples. Together, we reported a pair of rabbit monoclonal antibodies for sensitive and robust bioanalysis of total FGF21, supporting FGF21 functional research and drug development.