In vitro studies performed on human cell lines demonstrate the immunoregulatory properties of Interleukin-2 (IL-2) including: 1) enhancement of lymphocyte mitogenesis and stimulation of long-term growth of human Interleukin-2 (IL-2) dependent edll lines; 2) enhancement of lymphocyte cytotoxicity; 3) induction of killer cell (lymphokine-activated (LAK) and natural (NK)) activity; 4) induction of interferon-gamma production. Recombinant human Interleukin-2 (IL-2) is a highly purified protein with a molecular weight of approximately 15,300 Da. The chemical name is des-alanyl-1, serine-125 human interleukin-2. It is produced by recombinant DNA technology using a genetically engineered E. coli strain containing an analog of the human Human Interleukin-2 (IL-2) gene.