This antibody recognizes the same epitope as clone PC61. CD25, also known as the alpha chain of the interleukin-2 receptor (IL-2Rα), plays a significant role in the immune system. CD25 is a characteristic marker for Tregs, a subset of T cells that help suppress immune responses, thereby maintaining immune system homeostasis and self-tolerance. Tregs are particularly important in preventing autoimmune diseases and are also involved in the immune response to tumors. The expression of CD25 increases upon activation of T cells, making it a useful marker for identifying activated immune cells. High levels of CD25 expression are found in various hematological malignancies and are associated with Tregs within the tumor microenvironment. Targeting CD25 has been explored as a potential therapeutic strategy in cancer treatment, particularly in redirecting the immune response against tumors. There are monoclonal antibodies and other agents that target CD25, such as Daclizumab, which has been used in the treatment of multiple sclerosis and as an immunosuppressive agent in organ transplantation.