[Interleukin-2 and cancer treatment]

Interleukin-2 (IL-2) is a type of the lymphokine which Morgan et al. found in 1976 to be a specific growth factor of T lymphocytes. Initially, it was called the T cell growth factor (TCGF), but it was renamed interleukin-2 (IL-2) in 1979. IL-2 is an essential factor for the differentiation and growth of T cell and NK cell, and it is involved in the adaptive immune reaction through such cells. Thus, IL-2 can be expected to play an important role in the improvement of the immunologic adaptive function in various immune system failure type disease and in malignant tumors among others. With the recent production of recombinant IL-2, the latter's biological and immunological functions are gradually coming to light, and its clinical applicability is also being seen in terms of effectiveness. Thus, administration of IL-2 alone, the induction of IL-2-dependent, tumor-specific CTL (cytotoxic T lymphocyte), or the induction and growth by IL-2 of lymphokine-activated killer (LAK) cell, have paved the way for adoptive immunotherapy. The clinical phase I study of IL-2 (TGP-3) has been completed, and the second phase study is now in progress. A pilot study is also under way using LAK cells.