Recombinant Human CD161/CLEC5B-Fc Chimera (carrier-free)

Pricing & Availability
Regulatory Status
Other Names
KLRB1, CD161, NKRP1A, NKR, Killer cell lectin-like receptor subfamily B member 1, C-type lectin domain family 5 member B, HNKR-P1a, NKR-P1A, Natural killer cell surface protein P1A, NKRP1A, NKR-P1
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Product Citations
When human CD161/CLEC5B is immobilized at 2.0 µg/mL, biotinylated human CLEC2D binds with EC50 of 75 - 300 ng/mL. HRP Avidin (Cat. No. 405103) was used to detect the binding.
  • Human_CD161slashCLEC5B-Fc_Chimera_CF_RECOM_1_012119.png
    When human CD161/CLEC5B is immobilized at 2.0 µg/mL, biotinylated human CLEC2D binds with EC50 of 75 - 300 ng/mL. HRP Avidin (Cat. No. 405103) was used to detect the binding.
  • Human_CD161slashCLEC5B-Fc_Chimera_CF_RECOM_1_012119.png
    Stability testing for Human CD161/CLEC5B. Human CD161/CLEC5B was aliquoted in PBS, pH 7.2 at 0.2 mg/mL. One aliquot was frozen and thawed four times (4x Freeze/Thaw), and compared to a control kept at 4°C (Control). The samples were tested for their ability to bind human CLEC2D.
Cat # Size Price Save
780302 10 µg ¥16,640
780304 25 µg ¥30,240
780306 100 µg ¥99,800

CLEC5B (CD161, KLRB1, NKR-P1A) is a C-type lectin protein belonging to the natural killer (NK) cell receptor family. Human CLEC5B is a 225 amino acid type II transmembrane glycoprotein. It contains a 158 amino acid extracellular domain with several motifs characteristic of C-type lectins, a 29 amino acid transmembrane domain, and a 38 amino acid cytoplasmic domain. CLEC5B plays an inhibitory role on NK cells by binding to CLEC2D/LLT1 and inhibiting NK cell-mediated cytotoxicity as well as interferon-gamma secretion in target cells. CLEC5B also reportedly acts as a potentiation receptor on T cells to increase IFN-gamma production in concert with TCR engagement.  CLEC5B is known to be expressed by a distinct set of lymphocytes, in a subset of NK cells predominantly in intestinal epithelium and liver. It is also detected in peripheral blood T-cells, preferentially in adult T-cells with a memory antigenic phenotype.

Product Details
Technical data sheet

Product Details

Human CD161/CLEC5B, amino acid Gln67-Ser225 (Accession # Q12918) with a C-terminal human IgG Fc and 6His tag was expressed in CHO cells.
Molecular Mass
The 403 amino acid recombinant protein has a predicted molecular mass of approximately 46 kD. The DTT-reduced proteins migrate at approximately 60 kD, and non-reduced proteins migrate at approximately 115 kD by SDS-PAGE. The predicted N-terminal amino acid is Gln.
>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 protein as determined by the LAL method.
10 and 25 µg sizes are bottled at 200 µg/mL. 100 µg size is lot-specific and bottled at the concentration indicated on the vial. To obtain lot-specific concentration, please enter the lot number in our Concentration and Expiration Lookup or Certificate of Analysis online tools.
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.
When human CD161/CLEC5B is immobilized at 2.0 µg/mL, biotinylated human CLEC2D binds with an EC50 of 75 - 300 ng/mL. HRP Avidin (Cat. No. 405103) was used to detect the binding.


Additional Product 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

Measured by its ability to bind CLEC2D
Cell Sources
Interacts with acid sphingomyelinase/SMPD1
Cell Type
NK cells, T cells, Thymocytes
Biology Area
Cell Biology, Immunology, Innate Immunity, Signal Transduction
Molecular Family
CD Molecules, Soluble Receptors
Antigen References
  1. Lanier LL, et al. 1994. J. Immunol. 153:2417-28.
  2. Poggi A, et al. 1998. Eur. J. Immunol. 28:1611-6.
  3. Aldemir H, et al. 2005. J. Immunol. 175:7791-5.
  4. Rosen DB, et al. 2005. J. Immunol. 175:7796-9.
  5. Pozo D, et al. 2006. J. Immunol. 176:2397-406.
  6. Germain C, et al. 2010. J. Biol. Chem. 285:36207-15.
Gene ID
3820 View all products for this Gene ID
View information about CD161 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) = 10e6/ ED50 (ng/mL)
Go To Top Version: 1    Revision Date: 01/18/2019

For research use only. Not for diagnostic use. Not for resale. BioLegend will not be held responsible for patent infringement or other violations that may occur with the use of our products.


*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.


BioLegend Inc., 8999 BioLegend Way, San Diego, CA 92121
Toll-Free Phone: 1-877-Bio-Legend (246-5343) Phone: (858) 768-5800 Fax: (877) 455-9587


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