Human IL-4R alpha Biotinylated Antibody

Interleukin 4 (IL‑4) is a pleiotropic cytokine produced by activated T cells, mast cells, and basophils. The biological functions of IL‑4 are mediated by the binding of IL‑4 to high‑affinity cell surface receptor complexes. Two types of IL‑4 receptor complexes have been described. The type I IL‑4 receptor complex is composed of a high‑affinity IL‑4‑binding subunit (referred to as IL‑4 R alpha) and the common gamma chain that does not bind IL‑4 by itself. The type II IL‑4 receptor complex is composed of IL‑4 R alpha and IL‑13 R alpha1. Besides IL‑4 signals, the type II IL‑4 receptor complex can also transduce IL‑13 signals. In the type II complex, the IL‑4 R alpha subunit binds only IL‑4 and not IL‑13. Similarly, the IL‑13 R alpha1 subunit binds only IL‑13 and not IL‑4. The cDNA clones for both the human and mouse IL‑4 R alpha have been isolated and shown to encode an approximately 140 kDa type I transmembrane protein with a large cytoplasmic domain that is essential for signal transduction. In mouse cells, an alternatively spliced variant encoding a soluble secreted IL‑4 R alpha isoform has also been identified. Naturally occurring soluble IL‑4 R alpha that binds IL‑4 with high‑affinity has been found in mouse and human biological fluids.