Recombinant Human IL-2Rα

IL-2 receptor alpha chain (IL-2 Rα), also known as IL2RA, CD25 and TAC antigen, is a type I transmembrane glycoprotein. It is a component of high-affinity IL-2 receptors and thus is a key regulator of lymphocyte proliferation (1). IL-2 Rα is expressed on activated T cells and regulatory T cells and is capable of binding IL-2 with low affinity by itself. However, a ligand-induced high affinity heterotrimeric receptor complex is produced when IL-2 Rα is associated non-covalently with the IL-2 Rβ and IL-2 Rγ chains. Subsequently, the complex initiates intracellular signal pathways such as MAPK or JAK/STAT. IL-2 Rα is essential for regulation of both the size and content of the peripheral lymphoid compartment, probably by influencing the balance between clonal expansion and cell death following lymphocyte activation (2). Proteolytic processing of IL-2 Rα releases the entire extracellular domain thereby generating soluble IL-2 Rα (sIL-2 Rα). The secreted sIL-2 Rα is expressed on leukemia cells, lymphoma cells, newly activated T and B cells, as well as on approximately 10% of NK cells (3). Infection by the protozoan trypanosoma cruzi causes Chagas disease, characterized by a reduction in the amount of IL-2 Rα expressed on the surface of immune cells.

Measured by its ability to inhibit the IL-2-dependent proliferation of MO7e human megakaryocytic leukemic cells.⁵ In the presence of 30 ng/mL of recombinant human IL-2, the ED₅₀ for this effect is 0.15‑0.75 µg/mL.

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Glu22

Lyophilized

The predicted molecular weight of Recombinant Human IL-2 Rα is Mr 22 kDa. However, the actual molecular weight as observed by migration on SDS-PAGE is Mr 36 kDa.

22

This recombinant protein was 0.2 µm filtered and lyophilized from modified Dulbecco’s phosphate buffered saline (1X PBS) pH 7.2 – 7.3 with no calcium, magnesium, or preservatives.

The lyophilized protein should be stored desiccated at -20°C. The reconstituted protein can be stored for at least one week at 4°C. For long-term storage of the reconstituted protein, aliquot into working volumes and store at -20°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles.

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1. Leonard, WJ. et al. (2002) The EMBO Journal 21: 3051
2. Alt, FW. et al. (1995) Immnnity 3: 521
3. Greene, WC. et al. (1990) J Invest Dermatol. 94: 27S
4. Avanzi, G. et al. (1988) Br. J. Haematol. 69:359.