Interleukin-13 Receptor alpha 2 (IL-13 Ra2), also known as IL-13 Ra’, IL-13 binding protein, and CD213a2, is a widely expressed 55 kDa cytokine receptor that plays an important role in the Th2‑polarized immune responses characteristic of a variety of pathologies including parasitic infections and allergic asthma (1, 2). Mature mouse IL-13 Ra2 consists of a 313 amino acid (aa) extracellular domain with three fibronectin type-III domains, a WSxWS motif, a 21 aa transmembrane segment, and a 28 aa cytoplasmic domain (3). Within the ECD, mouse IL-13 Ra2 shares 64% and 94% aa sequence identity with human and rat IL-13 Ra2, respectively. A 40 kDa ‑ 50 kDa soluble form of mouse IL-13 Ra2 can be generated by alternate splicing or MMP-8 mediated shedding (4, 5). The biological effects of IL-13 and IL-4 are closely related in part due to a shared receptor system. IL‑13 binds to IL-13 Ra1 which then forms a signaling complex with IL-4 Ra (6, 7). IL-13 Ra2 functions as a decoy receptor by binding and internalizing IL-13 and preventing it from signaling through the IL-13 Ra1/IL-4 Ra complex (3, 8). IL‑13 Ra2 can also block IL-4 induced responses by inhibiting IL-4 bound IL-13 Ra1/IL-4 Ra receptor complexes even though it does not itself bind IL-4 (9, 10). Aside from its decoy function, IL‑13‑activated IL-13 Ra2 directly promotes the development of tissue fibrosis by inducing the transcription of TGF-beta (11). Soluble IL‑13 Ra2 retains ligand binding capability and attenuates responses to IL-13 but not to IL-4 (9, 12). The up‑regulation of transmembrane and soluble IL‑13 Ra2 during Th2-biased immune responses limits the extent of those responses (13 ‑ 15). IL‑13 Ra2 is expressed in some cancers, and its ability to block IL-13 and IL-4 contributes to tumorigenesis and metastasis (10, 16).