R&D Systems now offers a human Multi-color Flow Cytometry Kit (Catalog #FMC013) that can be used for single step staining and identification of human regulatory T (Treg) cells. The kit includes APC-conjugated anti-FoxP3, PE-conjugated anti-CD25, and PerCP-conjugated anti-CD4 antibodies, as well as specially formulated staining buffers and a goat IgG-APC isotype control. The APC-conjugated anti-human/mouse/rat polyclonal FoxP3 antibody (Catalog #IC3240A) and specially formulated FoxP3 staining Buffer (Catalog #FC011) are also now available individually. FoxP3 is a member of the forkhead box (Fox) family of transcription factors and is required for the differentiation of Treg cells. Treg cells negatively modulate physiological and pathological immune responses, and defects in their differentiation or function have been linked to inflammatory/autoimmune disorders.

Detection of FoxP3+ Cells by Flow Cytometry. Human PBMCs (A), mouse splenocytes (B), and rat splenocytes (C) were stained with the new APC-conjugated anti-human/mouse/rat FoxP3 polyclonal antibody (Catalog #IC3240), as well as PerCP-conjugated anti-CD4 (left panel) or PE-conjugated anti-CD25 (right panel). Dot plots show the relative FoxP3+ , CD4+ , and CD25+ cell populations. Quadrants were set based on isotype controls.