IL-4 can signal through type I and type II receptor complexes, which share a common γ chain (γc). The type I receptor contains in addition to the γ chain an IL-4Rα subunit, whereas the type II receptor contains the IL-13Rα. The secreted extracellular domain of IL-4Rα, called sIL-4Rα, binds IL-4 and antagonizes its activity. It plays an important role in regulating the differentiation of naive CD4 T cells and class switching to IgG1 and IgE. Recombinant Human sIL-4Rα is a 209 amino acid protein that corresponds to the entire extracellular domain of IL-4Rα.
Amino Acid Sequence
The ED 50 was determined by its ability to inhibit the IL-4 dependent proliferation of human TF-1 cells is ≤ 5.0 ng/ml (in the presence of 0.5 ng/ml of IL-4), corresponding to a specific activity of ≥ 2×10 5 units/mg.
Endotoxin level is <0.1 ng/μg of protein (<1EU/μg).
Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.1–1.0 mg/ml. Do not vortex. This solution can be stored at 2–8°C for up to 1 week. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at –20°C to –80°C.