Go Back IL-5 R alpha (322aa) - Fc Chimera

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A DNA sequence encoding the signal peptide and extracellular domain of human IL-5 R alpha (aa 1-342) was fused to the Fc region of human IgG1 (aa 90-330). The chimeric protein was expressed in modified human 293 cells.

Interleukin 5 (IL-5) plays an important role in B cell development by inducing the terminal differentiation of late-developing B cells. Additionally, IL-5 regulates the differentiation, survival and degranulation of eosinophils. IL-5 is expressed predominately by T-lymphocytes and mast cells, and to a lesser extent by eosinophils, natural killer cells and endothelial cells. IL-5 specifically binds to the IL-5 receptor-alpha (IL-5 R alpha; IL-5Ra) subunit expressed predominately on CD5+ B cells, eosinophils, mast cells, CD34+ stem cells, and basophils. Binding allows association with the common beta subunit (ßc), shared by the IL-3 and GM-CSF receptors. In addition to the membrane bound form of IL-5Ra, soluble forms of IL-5Ra have been identified and are inhibitory to IL-5 activity. There is also evidence to suggest that the levels of membrane bound and soluble IL-5 receptors are altered in disease states such as asthma, where there is an increase in the membrane bound form and a concomitant decrease in the soluble receptor form. Symansis IL-5 R alpha is produced as an ECD-Fc fusion protein with the aim of enhancing its activity. ECD-Fc fusion proteins have an advantage over soluble receptors because many receptors are only functional in dimeric form. Fusion to the Fc domain of IgG1 induces dimerization due to the ability of the Fc domain to form disulfide bonds. The resulting dimeric receptor (EDC-Fc) mimics the activated form of the receptor and possesses enhanced affinity for its cognate ligand relative to its monomeric form. For a review of the structure and function of IL-5 receptor please see Takatsu K (1995) Yakugaku Zasshi 115:570-583.