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
<0.01 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 <0.2 ng/mL.
The specific activity of recombinant human IL-2 is approximately >2.5 x 10⁷ IU/mg.
Measure by its ability to induce proliferation in NK cells.
The ED₅₀ for this effect is <46 ng/mL.

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