Ala 21 - Thr 153. Purity > 95% by SDS - PAGE. MW: 16 kDa with a 6xHis tag at the C-terminus. Interleukin-2 (IL-2) is a potent immuno-modulator, which mediates a wide range of immune and inflammatory responses and is important for the proliferation of T and B lymphocytes. IL-2 is one of the key cytokines for the immune system, tolerance and immunity. It has been approved for the treatment of metastatic renal cell carcinoma and metastatic melanoma in cancer immunotherapy with long term disease control. In addition to being used as monotherapy, IL-2 can also be combined with other anticancer immunotherapies, such as adoptive cell transfer, vaccination, and blockade of immune checkpoint inhibitory molecules, such as cytotoxic T lymphocyte-associated antigen 4 and programmed death 1 monoclonal-antibodies as a promising treatment for metastatic cancer.