Trabikibart (CSL311), a βc ( CSF2RB )-specific, fully human monoclonal antibody, binds to a unique epitope that is specific to the cytokine-binding site of the human βc receptor. Trabikibart has picomolar binding affinity for the human βc receptor. Trabikibart is a potent inhibitor of the combined effects of IL-3 , GM-CSF and IL-5 on the survival of eosinophils. Trabikibart has the potential for chronic inflammatory diseases research.