IL-2 is a secreted cytokine that regulates the proliferation of T and B lymphocytes. The IL-2 receptor is a heterotrimeric protein complex whose gamma chain is also shared by interleukin 4 (IL-4) and interleukin 7 (IL-7). The IL-2 gene in mature thymocytes is monoallelic, which represents an unusual regulatory mode to control the gene expression precisely. The targeted disruption of a similar gene in mice leads to ulcerative colitis-like disease, which suggests an essential role of this gene in the immune response to antigenic stimuli. Expression System Escherichia coli Sequence MAPTSSSTKKTQLQLEHLLLDLQMILNGINNYKNPKLTRMLTFKFYMPKKATELKHLQCLEEELKPLEEVLNLAQSKNFHLRPRDLISNINVIVLELKGSETTFMCEYADETATIVEFLNRWITFCQSIISTLT with polyhistidine tag at the C-terminus Species Human Tag polyhistidine tag at the C-terminus Endotoxin Level <0.05 EU per 1 µg of the protein by the LAL method. Activity Measure by its ability to induce proliferation in CTLL-2 cells. The ED50 for this effect is <3 ng/mL. The specific activity of recombinant human IL-2 is approximately >5 x 10⁶ IU/mg. Purity >98% as determined by SDS-PAGE. Ni-NTA chromatography Formulation The protein was lyophilized from a solution containing 1X PBS, pH 8.0. Reconstitution 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-2
