Recombinant Mouse IL-31 Protein, CF

Mouse Interleukin-31 (IL-31) is likely a secreted, 24‑33 kDa short-chain member of the alpha-helical IL-6 family of cytokines (1, 2). The mouse IL‑31 cDNA encodes a 163 amino acid (aa) precursor that contains a 23 aa signal peptide and a 140 aa mature protein (3, 4). The mature region shows four alpha‑helices which would be expected to generate a typical up-up-down-down topology. There are three potential sites for N‑linked glycosylation. Mature mouse IL-31 shares 29% and 63% aa sequence identity with human and rat IL-31, respectively. Neither mouse nor human IL-31 are active on their counterparts receptors (1). IL-31 is associated with activated T cells and is preferentially expressed by Th2 rather than Th1 cells (1). IL-31 signals via a heterodimeric receptor complex composed of a newly identified, 120 kDa, gp130-related molecule termed IL-31 RA (also GPL and GLM-R) and the 180 kDa oncostatin M receptor (OSM R beta) (4‑8). In the complex, IL‑31 directly binds to IL‑31 RA, not OSM R (4, 5). IL-31 signaling has been shown to involve the Jak/STAT pathway, the PI3 kinase/AKT cascade, and MAP kinase pathway. Although multiple isoforms of IL-31 RA are known, only a form that contains the entire length of the cytoplasmic domain is signaling-capable (4‑7). The IL-31 receptor is constitutively expressed by keratinocytes and upregulated by IFN-gamma on monocytes (1, 3). Other cells known to be responsive to IL-31 include bronchial epithelium, type II alveolar cells, goblet cells, and likely hematopoietic progenitor cells (9‑11). Functionally, it has been shown that IL-31 may contribute to clinical pruritis (itching) associated with nonatopic dermatitis (1, 3, 12). This may be a consequence of IL-31’s ability to induce keratinocyte secretion of multiple cytokines, including TARC, GRO‑ alpha, MIP‑3 beta and I-309 (1). In addition, IL-31 promotes proliferation of high density cell populations such as myeloid progenitor cells, but conversely suppresses proliferation of lung epithelial cells (1). Finally, IL-31 may actually have a modulating effect on T cell subsets, influencing the ratio between Th1 and Th2 cells (1).