Flex-T™ Custom HLA Tetramer

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Regulatory Status
Other Names
MHC tetramer, HLA tetramer, HLA monomer, MHC monomer, biotinylated HLA monomer
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280014 Custom
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CD8+ T cells are essential components of the immune system. They function through TCR recognition of antigens (peptide epitopes) presented by the class I MHC (HLA in humans) molecules. Thus, TCR recognition of cognate MHC/peptide complex can be utilized for the detection of antigen-specific CD8+ T cells. Due to the intrinsic low affinity of MHC/TCR interaction, the detection of antigen specific T cells requires enhanced binding avidity by multimerization of MHC/peptide monomers, ensuring the interaction of multiple MHC/TCR simultaneously. This can be accomplished by using streptavidin to tetramerize biotinylated MHC class I complexes.

Flex-T™ Custom HLA tetramers provide peptide loaded HLA tetramers ready to use for flow cytometric staining.

Product Details
Technical Data Sheet (pdf)

Product Details

Storage & Handling
Store between 4 and 8°C.


Recommended Usage

Please use this form to order the product: http://www.biolegend.com/custom_flex-t

For flow cytometric staining, the suggested use of this reagent is 2μl per test.

Antigen Details

Gene ID

Related FAQs

Is there any peptide length recommended?

There are no special requirements for the peptides. Peptides that naturally bind to MHC molecules will bind to Flex-T™ reagents. For class I molecules, typical length is about 8 – 10 amino acids. Class II molecules accommodate longer peptides, about 14 – 20 amino acids1.

1) Mohan JF and Unanue ER. Unconventional recognition of peptides by T cells and the implications for autoimmunity. Nat Rev Immunol. 2012 Oct;12(10):721-8.

What are MHC tetramers and what can you do with them?

The T-cell mediated innate immune response is defined by the interaction between antigen presenting cells and T cells, through the Major Histocompatibility Complex (MHC) and the T cell receptor (TCR). MHC molecules present a peptide to antigen-specific T cells that recognize this peptide. Soluble, monomeric MHC molecules bind very weakly to the TCR. However, by making a tetramer through a fluorescently labeled streptavidin conjugate, the complex binds to several TCRs, creating a more stable interaction and making it useful for flow cytometric detection of antigen specific T cells.

I am interested in finding novel peptides instead, are there any resources for this?

There are a number of databases and webpages that can help, these are three of them:



What are the specifications of the UV source?

Long-wave UV, 366 nm, 8 Watts (We recommend, for example, CAMAG cat# 022.9115, or Ultraviolet Crosslinker CL-1000). The distance from the solution to the light source should be 2 – 5 cm (approximately 0.8 – 3 inches).

What is Flex-T™?

Flex-T™ (Flexible-Tetramers) is BioLegend’s brand name for our Soluble MHC product line. It encompasses monomers, the ultraviolet (UV) peptide exchange technology, and all associated products and applications.

Do I need to know the sequence of the UV-labile peptide?

The sequence of the UV-labile peptide is not needed to use the reagent. MHC molecules are not stable without a peptide, so these peptides are used just for two purposes: stabilize the MHC molecules and serve as a place holder to be substituted by the peptide of interest.

Do you offer mouse monomers or tetramers?

Not currently.

Do you offer custom products and services?

Yes, please contact our Custom Solution Team with your request at cst@biolegend.com, or contact your local BioLegend representative.

How do I evaluate the efficiency of the peptide exchange?

Follow the protocol for HLA class I ELISA. An assay positive control is provided (Cat#280301) that can be diluted to a high, medium, and low concentration. Signal intensity can be correlated to affinity of the peptide.

What is the peptide exchange technology and what's the advantage of using it?

Flex-T™ MHC monomers are loaded with a peptide that can be degraded by the use of a UV light source. This allows for a peptide exchange when the UV irradiation is done in the presence of the peptide of interest (which is not UV-labile). This flexibility permits the screening of virtually any peptide of interest with enough affinity for the MHC allele that it is loaded onto.

Is it feasible to screen not just peptides, but also several specificities of antigen-specific T cells in one sample?

With the traditional pre-assembled Tetramer approach, this is difficult to do, and not cost-effective. With Flex-T™ technology, as there is more flexibility to assemble the tetramers, it is easy and affordable to screen a sample for several specificities2. To facilitate this approach, a combinatorial color coding system has been developed. Please visit the Flex-T™ webpage for a detailed description.

2) Hadrup SR et al. Parallel detection of antigen-specific T-cell responses by multidimensional encoding of MHC multimers. Nat Methods. 2009 Jul;6(7):520-6.

Is there any advantage in buying biotinylated monomers?

Yes, the same monomer can be assembled with different Streptavidin conjugates, providing great flexibility for color choices. Additionally, it can be stored frozen and the tetramer assembled shortly before the experiment. This increases the storage time of the reagent.

Go To Top Version: 1    Revision Date: 02.02.2017

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, www.biolegend.com/ordering#license). 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 www.biolegend.com
Toll-Free Phone: 1-877-Bio-Legend (246-5343) Phone: (858) 768-5800 Fax: (877) 455-9587

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