Description
Mouse Interleukin-13 (IL-13) is produced primarily by activated Th2 cells. IL-13 is a pleiotropic immune regulatory cytokine that promotes growth of human B cells; induces expression of germ line Ce transcripts, directs na?ve B cells to switch to the synthesis of IgE and IgG4, and induces expression of CD23 and Class II-MHC. In monocytes, IL-13 down-regulates FcgR expression; inhibits synthesis of proinflammatory cytokines, including TNF-a, IL-1b, IL-6 and IL-8; induces monocyte/macrophage fusion and mannose receptor expression. IL-13 inhibits the synthesis of IL-12, nitric oxide synthase and cyclooxigenase-2. The mouse IL-13 cDNA encodes a 131 amino acid protein that shares 58% identity with human IL-13 and exhibits cross-species activity on human cells. Additionally, IL-13 shares 30% sequence homology to IL-4 and the two cytokines exert overlapping biological activities. IL-13 binds to a heterodimeric receptor formed by the IL-13Ra and the IL-4Ra. The mouse IL-13 cDNA encodes a 131 amino acid protein containing a proposed 20 amino acid signal peptide. The 106 amino acid residue recombinant protein has a predicted molecular mass of approximately 11.5 kDa. The purified protein migrates anomalously on SDS-PAGE as a 9 kDa protein