Recombinant Human IL13

Human IL13 is expressed in activated T helper cells (resembling Th0, Th1, Th2), and T cells expressing CD8. The alpha chain of the IL13 receptor has weak binding activity for IL13. High affinity receptors are formed when the receptor alpha chains of IL13 and IL4 receptors are coexpressed. Different IL13 receptor structures have been shown to exist on various cell types and the IL13 receptor may share more than one component with IL4 receptor. IL13 down-modulates macrophage activity, reducing the production of pro-inflammatory cytokines and chemokines in response to IFN-gamma or bacterial lypopolysaccharides. IL13 enhances the production of the IL1 receptor antagonist IL1ra. IL13 also decreases the production of nitric oxide by activated macrophages, leading to a decrease in parasiticidal activity. IL13 induces differentiation of human monocytes, enhances survival time in culture, and also induces differentiation and proliferation and isotype switching in B cells.