Human IL-4R alpha 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.