Doing the FOXP3 trot
Regulatory T (Tregs) cells are key components in down-regulating immune responses, and have been shown to play a role in diseases ranging from cancer to autoimmune diseases and infections. Tregs are CD4 T cells most often characterized by the expression of forkhead box P3 (FoxP3). These cells also regarded as having have bright expression of CD25 and low expression of CD127, although a recent publication has shown a great heterogeneity in the phenotypes of Tregs found in patients with chronic lymphocytic leukemia. Demaret and coworkers demonstrate a one step technique for staining FoxP3 in order to identify these cells. FoxP3 is an intracellular antigen, and as such, fixation/permeabilization techniques are required for staining. In the approach presented here, a commercial no wash kit is used for staining these cells with FoxP3 as well as surface markers with good results. This expedited protocol might obviate the need to use surrogate staining, such as CD25high and CD127low on CD4 cells to identify Tregs. One might hope that this expedient method would facilitate samples in clinical trials being run on fresh rather than cryopreserved samples, as cryopreservation has been shown to negatively impactthe detection and quantification of Tregs.
Demaret et al., Cytometry Part B 2013; 84B: 187–193
Contributor: J. Philip McCoy Jr., Ph.D., Bethesda, MD.