IL-4 is a multi-functional cytokine that plays a critical role in the regulation of immune responses. It induces differentiation of naive helper T cells to Th2 cells. Upon activation by IL-4, Th2 cells subsequently produce additional IL-4 in a positive feedback loop. IL-4 is produced primarily by mast cells, Th2 cells, eosinophils and basophils. It is closely related and has functions similar to interleukin 13. This protein 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 is a key regulator in humoral and adaptive immunity. IL-4 plays a dominant role in the development of allergic inflammation and asthma. Also, it is crucial in the development of allergic airway inflammation originates. Recombinant protein corresponding to aa25-153 from IL-4, fused to His-Tag at C-terminal, expressed in HEK293 cells. Molecular Weight: ~16.1kD Biological Activity: Measured in a cell proliferation assay using TF-1 human erythroleukemic cell. The ED50 range 0.5ng/ml. Amino Acid Sequence: HKCDIT LQEIIKTLNS LTEQKTLCTE LTVTDIFAAS KNTTEKETFC RAATVLRQFY SHHEKDTRCL GATAQQFHRH KQLIRFLKRL DRNLWGLAGL NSCPVKEANQ STLENFLERL KTIMREKYSK CSS Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 6 months after receipt at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.