Recombinant Human IL-9

Interleukin-9 (IL-9), also known as P40 and MEA (mast cell growth-enhancing activity), is a 30-40 kDa glycosylated member of a cytokine family that includes Interleukins-2, -4, -7, -15, and -21. These proteins utilize heteromeric receptors containing the Common gamma chain (gamma c) in addition to ligand-specific subunits. IL-9 interacts selectively with IL-9 R which then associates with gamma c to form the functional receptor complex. IL-9 contributes to allergic inflammation, autoimmunity-induced inflammation, parasite clearance from the GI tract, and Treg-mediated immune suppression ^{[1, 2]}. It enhances the expansion and recruitment of mast cells and eosinophils as well as the production of IgE and Th2 cytokines ^[3-6]. It is required for anaphylactic responses to ingested allergens but not to systemic allergens ^[7]. IL-9 plays multiple roles in the development and function of subsets within the CD4+ T cell lineage ^[8]. It is expressed by activated Th9, Th17, Treg, and Th2 cells ^{[3, 9-12]}. IL-9 acts as an autocrine growth and activation factor for Th17, Treg, and mast cells ^{[3, 11, 13]}.

Reference

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[11]. Elyaman, W. et al. (2009) Proc. Natl. Acad. Sci. USA 106:12885.

[12]. Lu, L.-F. et al. (2006) Nature 442:997.

[13]. Stassen, M. et al. (2000) J. Immunol. 164:5549.