Used in immunological research to quantify levels of the interleukin-2 receptor alpha chain (CD25) in biological samples. This ELISA kit enables detection of soluble CD25 or membrane-bound CD25 shed into serum, plasma, or cell culture supernatants. It is particularly valuable in studies related to T-cell activation, immune regulation, and autoimmune diseases. Researchers also use it in cancer immunology, as elevated CD25 levels are associated with certain lymphomas and leukemias. The assay supports monitoring immune responses in therapeutic development, including checkpoint inhibitor studies and adoptive cell therapies.