Interleukin-5 receptor (IL-5R)

The Interleukin‑5 receptor is a heterodimeric type I cytokine receptor composed of an α subunit (IL‑5RA), which confers specificity for interleukin 5 binding, and a common β subunit (CSF2RB), which mediates signal transduction. The α chain is primarily expressed on eosinophils, some basophils, and B cell precursors. Upon ligand binding, the β chain activates intracellular signaling pathways involving Janus kinases such as JAK2. This receptor plays a central role in regulating eosinophil proliferation, activation, and survival—processes implicated in allergic inflammation and diseases like asthma. Therapeutic monoclonal antibodies targeting either the ligand or its receptor are approved for severe eosinophilic asthma[1][6].

Other names

IL-5RInterleukin 5 receptorCD125 (for the alpha subunit)IL5RA (for the alpha subunit)

Monoclonal antibodies block ligand binding or deplete target cells by antibody-dependent cell-mediated cytotoxicity (e.g., benralizumab binds to IL‑5Rα and induces eosinophil apoptosis via ADCC)[1].