| Background | 
                                Interleukin-4 (IL-4) is a key cytokine produced by activated T cells, mast cells, basophils, neutrophils and eosinophils. IL-4 is critical for the development of Th2-mediated responses, which is related to allergy and asthma. It can also regulate B cell responses, including survival, cell proliferation and gene expression. IL-4 also plays fundamental role for B-cell stimulation, including induction of the IgE isotype switch. | 
                            
                            
                            
                                | Synonyms | 
                                interleukin 4, BCGF, BCDF, B-cell Stimulating Factor (BSF-1), IL4 | 
                            
                            
                            
                                | Uniprot ID | 
                                P05112 | 
                            
                            
                            
                                | Molecular Weight | 
                                The protein has a calculated MW of 15.9 kDa.
The protein migrates as 12 kDa under reducing condition (SDS-PAGE analysis). | 
                            
                            
                            
                                | Expression System | 
                                Escherichia coli | 
                            
                            
                            
                                | Purity | 
                                >98% as determined by SDS-PAGE analysis. | 
                            
                            
                            
                                | Activity | 
                                Measure by its ability to induce TF-1 cells proliferation. The ED₅₀ for this effect is <0.2 ng/mL. The specific activity of recombinant human IL-4 is approximately >2.8 x 10⁷ IU/mg. | 
                            
                            
                            
                                | Endotoxin Level | 
                                <0.05 EU per 1 μg of the protein by the LAL method. | 
                            
                            
                            
                                | Protein Sequence | 
                                MHKCDITLQEIIKTLNSLTEQKTLCTELTVTDIFAASKNTTEKETFCRAATVLRQFYSHHEKDTRCLGATAQQFHRHKQLIRFLKRLDRNLWGLAGLNSCPVKEANQSTLENFLERLKTIMREKYSKCSS with polyhistidine tag at the C-terminus. | 
                            
                            
                            
                                | Protein Tag | 
                                His Tag (C-term) | 
                            
                            
                            
                                | Form | 
                                Lyophilized from a 0.2 µm filtered solution of PBS, pH 8.0. | 
                            
                            
                           
                              
                                | Application | 
                                Cell Culture |