Discription：Interleukin-4 （IL-4） is a pleiotropic cytokine that induces differentiation of naive helper T cells （Th0 cells） to Th2 cells and produced primarily by mast cells, Th2 cells, eosinophils and basophils. IL-4 is a key regulator in humoral and adaptive immunity and has many biological roles, including the stimulation of activated B-cell and T-cell proliferation, and the differentiation of B cells into plasma cells. It regulates the differentiation of naive CD4+ T cells into helper Th2 cells and immunoglobulin class switching to the IgG1 and IgE isotypes. Excessive IL-4 production by Th2 cells is associated with allergies. Mature human IL-4 shares 55％, 39％ and 43％ aa sequence identity with bovine, mouse, and rat IL-4, respectively. Human, mouse, and rat IL-4 are species-specific in their activities. IL-4 has a compact, globular fold, stabilized by 3 disulfide bonds. The recombinant Interleukin-4 is a 15kDa protein consisting of 129amino acid.
