Tac antigen
Tac an·ti·gen
CD25
A 55-kD monomeric glycoprotein low-affinity receptor for IL-2–IL-2R alpha. With p75 beta chain—CD122 antigen, IL-2Rbeta—CD25 forms a high affinity IL-2R complex.Normal expression
CD25 is expressed on activated T and B cells in the germinal centre, mantle zone, on activated macrophages and thymic medulla cells; it is absent from thymocytes and resting T and B cells.
Abnormal expression
Hairy cell leukaemia and Hodgkin lymphoma, and may be expressed on T and B cell NHLs, and HTLV I/II-associated T cell leukaemias.