|Cell culture supernatants||101%||86%-113%|
Proliferation of T lymphocytes is triggered by the interaction of IL-2 with its specific receptor following T lymphocyte activation. The receptor for IL-2 has three forms, generated by different combinations of three different proteins, the alpha chain (IL-2R alpha), the beta chain (IL-2R beta), and the gamma chain (IL-2R gamma). IL-2R alpha (also known as CD25) is a type I transmembrane protein present on activated T cells, activated B cells, some thymocytes, myeloid precursors, and oligodendrocytes. Soluble IL-2R alpha has been isolated and determined to result from extracellular proteolyisis. Soluble IL-2R alpha has been found in the plasma of patients with certain hematologic malignancies. Elevated plasma or serum concentration of soluble IL-2R alpha has also been reported as a biomarker of immune activation.