Tetramer assay

A tetramer assay is used to detect the presence of antigen specific T-cells. The main component of the assay is an MHC tetramer. This reagent has to be custom made for each antigen specific t-cell that one desires to detect. The MHC tetramer consists of four units of the MHC molecule bound together by a biotin molecule. A peptide from the antigen is attached to the MHC molecules. The MHC with its bound peptide will only bind the specific T-cells that respond to that peptide. The tetramer can be detected by flow cytometry using streptavidin labeled with a fluorescent dye.