IL2 is a secreted cytokine that is important for the proliferation of T and B lymphocytes. The receptor of this cytokine is a heterotrimeric protein complex whose gamma chain is also shared by interleukin 4 (IL4) and interleukin 7 (IL7). The expression of this gene in mature thymocytes is monoallelic, which represents an unusual regulatory mode for controlling the precise expression of a single gene. 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.
Interleukin-2 human recombinant produced in E. coli is a single, non-glycosylated mutein (variant form) of human IL-2 polypeptide chain containing 134 amino acids and having a molecular mass of 15517 Dalton. The IL-2 is purified by proprietary chromatographic techniques. Purity is greater than 98.0% as determined by RP-HPLC and SDS-PAGE. The ED50 as determined by the dose-dependent stimulation of murine CTLL-2 cells is < 0.0645 ng/ml, corresponding to a specific activity of 16.9 MIU/mg.
Protein quantitation was carried out by two independent methods: UV spectroscopy at 280 nm using the absorbency value of 0.614 as the extinction coefficient for a 0.1% (1 mg/ml) solution; and analysis by RP-HPLC using a calibrated solution of IL-2 as a reference standard. The protein (1.1 mg/ml) was lyophilized after extensive dialysis against 0.17 mg sodium monobasic and 0.89 mg dibasic sodium phosphate buffer to a pH=7.5.
The sequence of the first five N-terminal amino acids was determined and was found to be Met-Ala-Pro-Thr-Ser. Our Interleukin-2 has an Ser substitute for Cysteine at position 126.