Interleukin 2: a review.

Interleukin 2 (IL 2) is a central mediator of the growth and functional activity of B- and T-cells, and cytotoxic cells, including Natural Killer and Lymphokine Activated Killer cells. Significant defects in the production of, and response to, IL 2 have been described in a variety of congenital and acquired immunodeficiency states. IL 2 has demonstrated major anti-tumor activity in animal models. The biochemistry and molecular biology of IL 2 and its gene are reviewed, along with data regarding the IL 2 receptor, normal T-cell activation, abnormalities in IL 2 production and response in immunodeficiency states and leukemia, and initial explorations of IL 2 in the treatment of human cancer.