The antibody reacts with the α chain of the Interleukin-2 Receptor (55 kDa glycoprotein). CD25 is expressed on activated T-lymphocytes and B-lymphocytes.
CD25 is the alpha chain of the IL-2 receptor. It is a type I transmembrane protein present on activated T cells, activated B cells, some thymocytes, myeloid precursors, and oligodendrocytes that associates with CD122 to form a heterodimer that can act as a high-affinity receptor for IL-2. CD25 is expressed in most B-cell neoplasms, some acute nonlymphocytic leukemia's, neuroblastomas, and tumor infiltrating lymphocytes. Its soluble form, called sIL-2R may be elevated in these diseases and is occasionally used to track disease progression.Synonyms: IL-2 receptor alpha subunit, IL-2-RA, IL2-RA, Interleukin-2 receptor alpha chain, TAC antigen, p55