Used in immunological research to study eosinophil activation and differentiation, particularly in asthma and allergic disease pathways. Serves as a capture or detection target in ELISA and flow cytometry assays due to the His tag facilitating purification and detection. Employed in drug development for targeting IL-5 signaling in eosinophilic disorders. Supports binding studies with anti-IL-5Rα antibodies and therapeutic agents to evaluate inhibition efficacy.