Recombinant Human IL-4Rα

IL-4 receptor alpha (IL-4 Rα), also known as IL4RA and CD124, is the alpha chain of the Il-4 receptor which binds to both IL-4 and IL-13 to regulate immune and allergenic responses. Hematopoietic cellular responses to IL-4 are mediated by a high affinity receptor complex comprised of the IL-4 Rα subunit and the common cytokine γ chain (CD132) (1). In non-hematopoietic cells, the IL-4 Rα subunit associates with the IL-13 Rα chain and serves as a functional complex for IL-13. IL-4 Rα is a single-pass type I transmembrane protein and similar to those present in the IL-2 receptor and GM-CSF receptor ß-chains. As a receptor for both IL-4 and IL-13, IL4 Rα couples to the JAK1/2/3-STAT6 pathway, and is involved in regulating IgE production and chemokine and mucus production at sites of allergic inflammation, as well as promoting differentiation of Th2 cells (2). The secreted extracellular domain of IL4 Rα, called sIL-4 Rα, can inhibit IL-4-mediated cell proliferation and IL-5 up-regulation by T cells but it has no signaling abilities. Allelic variations in the IL-4 Rα gene have been associated with atopy, a condition that can manifest itself as allergic rhinitis, sinusitis, asthma or eczema (3).