Interleukin-2 receptor subunit alpha (CD25) (CD25)

Interleukin-2 receptor subunit alpha, commonly referred to as CD25, is a type I transmembrane glycoprotein that serves as a critical component of the high-affinity interleukin-2 (IL-2) receptor complex (UniProt: P01589). While CD25 itself possesses low affinity for IL-2, its association with the IL-2 receptor beta (CD122) and gamma (CD132) chains allows for high-affinity ligand binding, which is essential for the robust proliferation and signal transduction of activated T-cells (NCBI Gene: 3559). CD25 is constitutively expressed at high levels on regulatory T cells (Tregs) and is rapidly upregulated on effector T cells following antigenic stimulation, making it a marker of lymphocyte activation. In clinical contexts, CD25 is overexpressed in various hematological malignancies, including Adult T-cell leukemia/lymphoma and Hairy cell leukemia, and is a central mediator in the pathogenesis of autoimmune disorders and allograft rejection (StatPearls: IL-2 Receptor). Pharmacological targeting of CD25 involves monoclonal antibodies such as Basiliximab and Daclizumab, which function as IL-2 antagonists to prevent transplant rejection or treat multiple sclerosis (DrugBank: DB00074, DB00111). Additionally, the receptor is utilized as a docking site for antibody-drug conjugates and immunotoxins designed to selectively eliminate activated pathogenic T cells or tumor cells.

Other names

IL2RATAC antigenp55Interleukin-2 receptor alpha chainIDDM10TCGFR

Competitive antagonism of interleukin-2 binding to the high-affinity IL-2 receptor complex to inhibit T-lymphocyte activation and proliferation; targeted delivery of cytotoxic moieties via antibody-drug conjugates (ADCs) or immunotoxins to CD25-expressing malignant or activated cells.