Interleukin II (60-70) is a peptide with the sequence NH2-LEU-THR-PHE-LYS-PHE-TYR-MET-PRO-LYS-LYS-ALA-COOH, MW=1373.7. Interleukin 2 (IL-2) is a type of cytokine signaling molecule in the immune system, regulating the activities of white blood cells.