The use of MHC tetramers for the detection of antigen specific T cells has been a well-established technique since it originally gained prominence in the mid-1990s. Since then, the sophistication of MHC tetramer and multimer design as well as its sensitivity in detecting target T cells has been steadily improving. Most applications of MHC Tetramers involve the use of Flow Cytometry to enumerate, purify or sort specific T cells, but in some cases, it is possible to use tetramers to visualize entire immunological processes taking place inside a whole body.
We want to bring to your attention a recent paper by Welsh and Song et. al. (Plos Biology Feb, 2020)1. In their study, while constantly using MHC Class II tetramers to detect and enumerate pathogenic T cells, responsible for the progression of Rheumatoid Arthritis (RA) as well as Experimental Autoimmune Encephalomyelitis (EAE) induced in mice models, the group performed a number of imaging trials. This imaging procedure involved a modified in vivo NIRF whole-body imaging technique described in the paper. The group was successful in identifying a co-localized population of Collagen peptide specific T-cells and a molecular probe specific for denatured Collagen protein molecules using an IRDye800CW-conjugated CII(280–294) peptide loaded HLA-DR1 tetramer.