Major histocompatibility complex (MHC) class I and class II molecules share the task of presenting peptides on the cell surface for recognition by T cells and play a pivotal role in the adaptive immune system.
Peptide-MHC (pMHC) complexes are recognized by CD4+ and CD8+ T cells expressing a repertoire of hypervariable αβ T cell receptors (TCRs). The interaction between the pMHC complex and a cognate TCR is short lived and of low affinity. By the multimerization of four pMHC molecules on a streptavidin scaffold, the tetramer binds to TCR with high affinity and specificity. Thus, pMHC tetramers can be used to identify, monitor, and handle T cells through direct and specific staining.
The pMHC molecules including HLA-A, HLA-B, HLA-C and HLA-DR are biotinylated. Available formulations are monomers and tetramers.
More than 30 MHC class I allotypes are available to be made into tetramers with optional labels.
The tetramers with phycoerythrin (PE) and allophycocyanin (APC) fluorochromes are available for flow cytometric analysis to characterize and quantify epitope specific T cells.