Clone REA570 recognizes the human CD25 glycoprotein, also known as the low-affinity interleukin-2 receptor alpha chain (IL-2Rα). It associates with IL-2 receptor β (CD122) and γ chains (CD132) to form a high affinity IL-2R complex. CD25 is expressed on activated T and B cells, on macrophages, and on a subset of non-activated CD4+
regulatory T cells. Clone REA570 recognizes epitope region A.