Human Interleukin-2 (IL-2) is a lymphokine which biological effects include activation and proliferation of T cells, B cells, and other lymphokine activated killer cells. Human IL-2 is composed of 133 amino acids, including 3 cysteine residues, two of which are involved in a disulfide bond essential for biological activity. Human and murine IL-2 are 62% homologous, and human IL-2 has been found to be active on murine cell lines. >95% pure. Lyophilized in the presence of stabilizer (mannitol), low levels of SDS (preventing aggregation), and Sodium Phosphate.