Recombinant Human IL4

IL4 is produced mainly by a sub-population of activated T helper cells which also secrete IL5 and IL6. The biological activities of IL4 are mediated by a specific receptor, the extracellular domain of which is related to the receptors for EPO, IL6, and the beta chain of the IL-2 receptor. IL4 participates in several B-cell activation processes as well as of other cell types. A co-stimulator of DNA-synthesis, IL4 induces the expression of class II MHC molecules on resting B-cells, enhances both secretion and cell surface expression of IgE and IgG1, and also regulates the expression of the low affinity Fc receptor for IgE on both lymphocytes and monocytes. Pre-treatment of macrophages with IL4 prevents the production of IL1, TNF-alpha and prostaglandins in response to activation of the cells by bacterial endotoxins or IFN-gamma.