Hu Recom IL-13, 10 µg

STEMCELL Technologies supplies Human Recombinant IL-13 as a research-use reagent expressed in E. coli and presented as a lyophilized powder from a sterile-filtered solution containing sodium citrate at pH 3. Interleukin-13 (IL-13) is a cytokine involved in type 2 immune responses and is expressed by T helper type 2 (Th2) cells and group 2 innate lymphoid cells (ILC2s). The cytokine binds a receptor composed of IL-4Rα together with IL-13Rα1 or IL-13Rα2, which is expressed on B cells, basophils, eosinophils, mast cells, endothelial cells, fibroblasts, monocytes, macrophages, respiratory epithelial cells, and smooth muscle cells. Engagement of this receptor activates the JAK/STAT and IRS-1/IRS-2 signalling pathways.

In vivo, IL-13 has roles in resistance to extracellular helminth parasites by regulating gastrointestinal parasite expulsion, as well as in airway hyperresponsiveness, allergic inflammation, tissue remodelling, tumor cell growth, and fibrosis. The supplied recombinant protein is described as a variant of wild-type IL-13 and as not species-specific but with greater activity on human cells compared with mouse cells.

The product has a predicted molecular mass of 12.6 kDa and a stated purity of ≥ 95%. Specific activity is ≥ 2 x 10^5 units/mg, determined by a cell proliferation assay using TF-1 cells with an EC50 of ≤ 5 ng/mL; a representative assay gave an EC50 of 3-4 ng/mL. Endotoxin level is ≤ 1 EU/μg protein, measured by kinetic Limulus amebocyte lysate (LAL) analysis. The recommended storage condition is -20 to -80 °C, with a stated shelf life of 12 months from the date of receipt. The lyophilized product is reconstituted in 10 mM hydrochloric acid to at least 0.1 mg/mL by pipetting the solution down the sides of the vial; vortexing is advised against.