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.
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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. |
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