Exbio — About exbio — Blog — Detection of regulatory T cells using flow cytometry

Detection of regulatory T cells using flow cytometry

Regulatory T cells (Tregs) have become an attractive topic of research for their ability to suppress collateral damage triggered by immune responses against pathogens and allergens, and for their role in the process of self-tolerance, as well as maternal tolerance to the fetus during pregnancy, and in maintaining of homeostasis with commensal microbiota. Tregs are usually characterized as CD4+ CD25high T-cells expressing the transcription factor FOXP3. Such phenotype is found in 5-12% of human peripheral blood CD4+ T-cells. Tregs can be further distinguished into the so-called “natural” Tregs originating in thymus (tTreg cells) and the peripherally induced Tregs (pTreg cells). The discrimination between tTregs and pTregs is still disputable, however, several proteins have been proposed to be the tTreg defining marker, such as the transcription factor Helios, and Neutropilin-1.

TregFlowEx Kit (cat. no. ED7417) is designed for the detection of regulatory T-cells in human peripheral blood or human umbilical cord blood using flow cytometry. It contains fixation and lysing solution, permeabilizing solution, blocking buffer, cell surface antigens staining reagent (CD4 FITC/CD25 PE), and intracellular antigen staining reagent (FOXP3 APC). Helios (a tTreg marker) can be detected by a separately provided PE-Cy™7 conjugated antibody (cat. no. T7-771-T100), that is not included in TregFlowEx Kit.

Fig.1: Tregs affect multiple immune responses. In the blood they can be identified as CD4+CD25+FOXP3+ cells. TregFlowEx Kit contains a set of fluorochrome-conjugated antibodies that detect CD4 in FITC channel (green), CD25 in PE channel (orange), and FOXP3 in APC channel (red).

Fig. 2: Visualization of CD4+ lymphocytes plotted according to their CD25 and FOXP3 expression. The Treg cells (CD4+CD25+FOXP3+) are found in the upper right quadrant.