Recombinant Human IL-21R (carrier-free)

Pricing & Availability
Regulatory Status
Other Names
Interleukin-21 receptor, IL-21 receptor, IL-21R, novel interleukin receptor, NILR, CD360
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Product Citations
Human IL-21R inhibits the IFNγ production induced by IL-21 in human NK-92 cells in a dose dependent manner.
  • Human_IL-21R_RECOM_1_040518
    Human IL-21R inhibits the IFNγ production induced by IL-21 in human NK-92 cells in a dose dependent manner.
  • Human_IL-21R_RECOM_2_040518
    Stability testing for human IL-21R. Human IL-21R was aliquoted in PBS at 0.2 mg/ml; one aliquot was kept at 4°C (control) and another was freeze-thawed four times (4 x freeze-thaws). After this procedure, the samples were tested by its property to inhibit the IFNγ production induced by human IL-21 in human NK-92 cells.
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773102 10 µg 62€
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773104 25 µg 90€
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IL-21R is a type I transmembrane protein, belonging to the class I cytokine receptor family. IL-21R contains the WSXWS motif, closely resembling IL-2Rβ and IL-4Rα. Intracellular domain of IL-21R includes the Box 1 and Box 2 elements, which are similar to the IL-9R intracellular region. IL-21R is expressed on B cells and at various levels on NK and T cells, but it is up-regulated after activation. Some studies indicated high levels of IL-21R in some leukemia and lymphoma. IL-21R expression is also elevated by CD40 triggering. IL-21R forms a heterodimer with common γ subunit (CD132), which is shared by the receptors for other interleukins, including IL-2, IL-4, IL-7, IL-9 and IL-15. Upon IL-21 ligation, IL-21R associates with JAK1 and induces phosphorylation cascade and STAT1, 3, 5 transduction pathways. Several evidences shown that IL-21/IL-21R signaling is essential for proliferation and differentiation of B, NK and T cells. In normal B cells, IL-21 mediates cell proliferation, growth arrest, and terminal differentiation, or apoptosis, depending on their activation status. In addition, mice lacking IL-21R have increased production of serum IgE but decreased IgG1. After immunization, antigen-specific IgG production was impaired, indicating IL-21/IL-21R is critical for regulating immunoglobulin production. Though B cell development and acute CD8+ T cell response are normal in IL-21R-deficient mice, development of memory B cells and maintenance of T cell function during chronic viral infection are impaired. IL-21/IL-21R complex can enhance NK cytotoxic activity and IFNγ production. In human, the loss of function in IL-21R gene leads to autosomal recessive IL21R immunodeficiency (IL21RID), resulting in dysfunction of B cells, T cells and NK cells, and a primary immunodeficiency syndrome. 

Product Details
Technical data sheet

Product Details

Human IL-21R, amino acid (Cys20-Pro236) (Accession: # Q9HBE5.1) with a C-terminal 6His tag, was expressed in CHO cells.
Molecular Mass
The 223 amino acid recombinant protein has a predicted molecular mass of approximately 25.83 kD. The DTT-reduced and non-reduced protein migrates at approximately 50 kD by SDS-PAGE. The predicted N-terminal amino acid is Cys.
> 95%, as determined by Coomassie stained SDS-PAGE.
0.22 µm filtered protein solution is in PBS, pH 7.2.
Endotoxin Level
Less than 0.1 EU per µg cytokine as determined by the LAL method.
10-25 µg sizes are bottled at 200 µg/mL.
Storage & Handling
Unopened vial can be stored between 2°C and 8°C for up to 2 weeks, at -20°C for up to six months, or at -70°C or colder until the expiration date. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C or colder. Stock solutions can also be prepared at 50 - 100 µg/mL in appropriate sterile buffer, carrier protein such as 0.2 - 1% BSA or HSA can be added when preparing the stock solution. Aliquots can be stored between 2°C and 8°C for up to one week and stored at -20°C or colder for up to 3 months. Avoid repeated freeze/thaw cycles.
The ED50 = 0.02 - 0.10 µg/mL as determined by its ability to inhibit human IL-21-induced IFNγ production on NK92 cells (in the presence of 10 ng/ml of human IL-21, Cat. No. 571202). Human IFN-γ ELISA MAX™ Deluxe Kit (Cat. No. 430104) was used to measure IFNγ production.


Application Notes

BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue-ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are verified in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at

Antigen Details

Cytokine receptor

Resting and activated B cells, T cells, NK cells and dendritic cells, activated macrophages, leukemia, lymphoma.

IL-21/IL-21R induces T and B cell proliferation, B cell Ig class switching to IgG production, decreases dendritic cell function, enhances differentiation of effector and central memory T cells, and regulates T cell and hematopoietic progenitor cell homeostasis.
Biology Area
Immunology, Innate Immunity
Molecular Family
CD Molecules, Cytokine/Chemokine Receptors, Soluble Receptors
Antigen References
  1. Parrish-Novak J, et al. 2000. Nature. 408: 57-63.
  2. Hamming OJ, et al. 2012. J. Biol. Chem. 287: 9454-60.
  3. Fröhlich A, et al. 2009. Science. 324: 1576-80.
  4. de Totero D, et al. 2006. Blood 107: 3708-15.
  5. Ozaki K, et al. 2002. Science 298: 1630-4.
  6. Kasaian MT, et al. 2002. Immunity 16: 559-69.
  7. Rankin AL, et al. 2011. J. Immunol. 186: 667-74.
  8. Kotlarz D, et al. 2013. J. Exp. Med. 210:433-43.
  9. Akamatsu N, et al. 2007. Cancer Lett. 256:196-206.
  10. Mehta DS, et al. 2004. Immunol. Rev. 202: 84-95.
Gene ID
50615 View all products for this Gene ID
View information about IL-21R on

Related FAQs

Why choose BioLegend recombinant proteins?

     • Each lot of product is quality-tested for bioactivity as indicated on the data sheet.
     • Greater than 95% Purity or higher, tested on every lot of product.
     • 100% Satisfaction Guarantee for quality performance, stability, and consistency.
     • Ready-to-use liquid format saves time and reduces challenges associated with reconstitution.
     • Bulk and customization available. Contact us.
     • Learn more about our Recombinant Proteins.

How does the activity of your recombinant proteins compare to competitors?

We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!

What is the specific activity or ED50 of my recombinant protein?

The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.

Have your recombinants been tested for stability?

Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.

Does specific activity of a recombinant protein vary between lots?

Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.

How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?

Use formula Specific activity (Units/mg) = 10^6/ ED50 (ng/mL)

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*These products may be covered by one or more Limited Use Label Licenses (see the BioLegend Catalog or our website, BioLegend products may not be transferred to third parties, resold, modified for resale, or used to manufacture commercial products, reverse engineer functionally similar materials, or to provide a service to third parties without written approval of BioLegend. By use of these products you accept the terms and conditions of all applicable Limited Use Label Licenses. Unless otherwise indicated, these products are for research use only and are not intended for human or animal diagnostic, therapeutic or commercial use.


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