Recombinant Human IL-5R alpha/CD125 Protein (C-His)

Measured by functional ELISA. Immobilized recombinant human IL-5Rα binds recombinant human IL-5 and reference anti-IL-5Rα antibody (benralizumab class) with EC50 values in the ng/mL range.

The interleukin-5 receptor alpha chain (IL-5Rα, CD125) is the cytokine-binding subunit that defines eosinophil and basophil identity. Expressed specifically on the eosinophil lineage, it pairs with the common beta chain to transduce IL-5 survival and activation signals; unlike IL-5 itself, the receptor is directly cross-linked and internalized by therapeutic antibodies. Benralizumab exploits this biology with a fucosylated Fc engineered for potent NK-cell-mediated ADCC, depleting eosinophils in severe asthma and hypereosinophilic syndrome. Recombinant IL-5Rα extracellular domain enables ligand-blocking assays, anti-receptor drug screening and eosinophil-depletion potency testing for this growing respiratory-medicine arena.