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Immudex Dextramer™ Technology

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MHC Dextramer™ Reagents

Immudex specializes in the detection of antigen-specific T-cells and produces and sells MHC multimer reagents that are based on the Dextramer™ Technology.

MHC Dextramer™ reagents are superior for the detection of antigen-specific T cells using flow cytometry and immunohistochemistry. 

MHC Dextramer™ - Products & Ordering

MHC Dextramer™ reagents are manufactured by Immudex, Copenhagen, Denmark and sold all over the world.

 

Ordering

MHC Dextramers can detect low affinity antigen-specific T cells, Tetramers cannot

Efficient detection of antigen specific T-cells depends on sensitive, high quality reagents. The MHC Dextramer™ reagents are a new generation of fluorescent MHC multimers that are particularly efficient in the detection of T-cells carrying T-cell receptors with very low affinity for MHC. The Dextramer™ reagents carry more MHC-molecules and more fluorochromes than conventional MHC multimers and are produced to the highest standards ensuring reproducibility in every experiment. MHC Dextramer™ reagents thus provide the following benefits:

Brighter staining, Higher resolution, Lower background, Higher stability, Minimal lot-to-lot variation

The MHC Dextramer™ reagents can be used to detect antigen-specific T-cells in fluid cell samples (e.g. blood, cultured cell lines, CSF, lymph, synovial fluid) using flow cytometry, or antigen-specific T-cells may be detected in situ in tissue sections.

Fields of application:

  • Monitoring vaccine studies
  • Monitoring effect of Immunotherapy
  • Determination of immune status (e.g. in connection with transplantation and other immunodeficiency)
  • Monitoring T-cell responses in infectious disease, cancer, autoimmunity and other malignancies
  • Detection of antigen-specific T-cell responses in immunological research

The Dextramer™ Technology

MHC Dextramer™ reagents are fluorescent labeled MHC multimers that can be used to detect antigen-specific T cells in fluid cell samples and solid tissue samples.

Detection of antigen-specific T-cells with MHC multimers
T-cells carry T-cell receptors (TCRs) that recognize specific MHC-peptide complexes displayed on the surface of antigen-presenting cells. This specific interaction between T cells and MHC-peptide complexes has been used to detect and isolate distinct populations of T cells with specificity for a given MHC-peptide complex. The individual TCR has low affinity for the MHC-peptide complex, which makes it difficult to detect or isolate T cells with similar specificities using monomer MHC-peptide complexes. The introduction of so-called MHC multimers has solved this problem. MHC multimers are reagents that carry multiple MHC-peptide complexes, and thus have the ability to interact simultaneously with multiple TCRs on a single T cell, allowing for a much more stable interaction between the reagent and the T cell. Multimeric MHC reagents bind with higher affinity as a result of the increased avidity. Fluorescent-labeled MHC multimers are used to detect and quantify antigen-specific T cells in fluid samples (e.g. blood, synovial fluid) by flow cytometry, and can be used for in situ detection (e.g. in solid tumors) using immunohistochemistry (IHC). MHC multimers may also be used to isolate antigen specific T-cell populations.

MHC Dextramer™ Reagents
The MHC Dextramer™ consists of a dextran polymer backbone carrying an optimized number of MHC and fluorochrome molecules. MHC Dextramer™ reagents carry more MHC molecules and more fluorochromes than conventional MHC multimers. This increases their avidity for the specific T-cell and enhances their staining intensity, thereby increasing resolution and the signal-to-noise ratio. An optimized formulation of the MHC Dextramer™ products ensures minimal background staining. The dextran polymer backbone stabilizes the conformation of the attached proteins, the MHC-peptide complexes and fluorochromes. Thus, MHC Dextramer™ reagents are highly stable reagents.

MHC Dextramers are suitable for basic and clinical research in a number of applications including drug and vaccine development.

MHC Dextramers are produced to the highest standards using purified single components, and without risk of peptide contamination from a peptide exchange reaction as Immudex’s production method involves no such exchange reaction. Every single product is quality-controlled for fluorescence and correct folding of MHC-peptide complexes. This ensures high reproducibility and minimal lot-to-lot variations.

Performance of MHC Dextramer™ Reagents

MHC Dextramer™ reagents are used in the study of antigen-specific T cells. High avidity, brightness and excellent resolution make MHC Dextramer™ reagents the superior choice for detection of antigen-specific T-cells in flow cytometry and immunohistochemistry.

Flow cytometry
The MHC Dextramer™ reagents come with any of three different flurochromes (PE, APC or FITC). When using flow cytometry they may be used to accurately monitor CD8+ T-cell responses in blood, CSF or other fluid cell samples.

Below the benefits of using Dextramer™ reagents compared to conventional MHC multimers are shown.

MHC Dextramers can detect low affinity antigen-specific T cells which Tetramers cannot

 (Preliminary data kindly provided by independent UK lab)
A, B, and C: Flow cytometry analysis of a cell sample constituting 99% “negative” HPBMC cells spiked with 1% cells of a T- cell line specific for the multimer reagents. Cells were stained with either Tetramers or Dextramers carrying pMHC with A) low affinity for TCR, B) medium affinity for TCR, or C) no affinity for TCR (negative control). Gated cells; live singlets, CD3+, CD14- and CD19-. D) Signal intensity of the T-cell line when stained with the respective MHC multimers. Cell count and multimer signal is shown for each of the three multimer specificities. Given KD-values are for monomeric pMHC-TCR interaction as measured by SPR.

Dextramers have stronger signals, less background staining

Ficoll-purified human peripheral blood mononuclear cells (HPBMC) were stained with Dextramer™, Tetramer and Pentamer according to each product’s recommended procedures. Gating strategy:
CD4-, CD14- and CD3+. As may be seen, MHC Dextramer™ reagents provide the highest resolution yet has the lowest background staining.

Dextramers stain 10x stronger

(The data was kindly provided by David Lissauer, Karen Piper, Professor Mark Kilby and Professor Paul Moss, Birmingham University, Birmingham, UK)

An approximately 10-fold brighter staining of a human T cell clone specific for the HLA-A2 restricted HY derived epitope FIDSYICQV is observed when stained with HLA-A2(FIDSYICQV)/PE Dextramer™ than with HLA-A2(FIDSYICQV)/PE Tetramer.