IL-4 is a pleiotropic cytokine produced by activated T cells. The IL-4 receptor also binds to IL-13, which may contribute many overlapping functions of IL-4 and IL-13. STAT6, a signal transducer and activator of transcription, is important in mediating the immune regulatory signal of this cytokine. This gene, IL-3, IL-5, IL-13, and CSF2 form a cytokine gene cluster on chromosome 5q. IL-4, IL-13 and IL-5 are found to be regulated coordinately by several long-range regulatory elements in an over 120 kilobase range on the chromosome. Two alternatively spliced transcript variants of this gene encoding distinct isoforms have been reported.
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<0.1 EU per 1 μg of the protein by the LAL method.
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.
>98% as determined by SDS-PAGE. Ni-NTA chromatography
The protein was lyophilized from a solution containing 1X PBS, pH 8.0.
It is recommended to reconstitute the lyophilized protein in sterile H₂O to a concentration not less than 100 μg/mL and incubate the stock solution for at least 20 minutes to ensure sufficient re-dissolved.
SDS-PAGE analysis of recombinant human IL-4