Interleukin 21 receptor (IL21R), recombinant human protein is supplied as a lyophilized powder. It is suitable for use in analysis of protein structure. In general, recombinant proteins can also be used as an immunogen, as a protein standard, or in cell biology research applications.

This recombinant protein was expressed from a DNA sequence encoding the human IL21R (Q9HBE5-1) extracellular domain (Met 1-Pro 236) was expressed, with a polyhistidine tag at the C-terminus.

Activity:
1. Measured by its ability to bind human IL21 in a functional ELISA.
2. Measured by its ability to inhibit IL21-induced Interferon gamma secretion by human natural killer lymphoma NK-92 cells. The ED₅₀ for this effect is typically 1-5 ng/ml in the presence of 100 ng/ml of recombinant human IL21.
3. Measured by its ability to inhibit IL21 induced Interferon gamma secretion by human natural killer lymphoma NK-92 cells. The ED₅₀ for this effect is typically 50-200 pg/mL in the presence of 10 ng/ml of recombinant human IL21.

Formulation: Lyophilized in PBS, pH7.4, 5% Mannitol, 5% Trehalose, and 0.02% Tween-80.

Reconstitution: Dissolve the protein in sterile double distilled water to a concentration of 25 mg/ml or lower. It is recommended that the protein be aliquoted and be used as soon as possible. Store aliquots under sterile conditions at -20°C. Avoid repeated freeze-thaw cycles.

Expiration Date: Expires one year from date of receipt when stored as instructed.