The shared and contrasting roles of interleukin-2 (IL-2) and IL-15 in the life and death of normal and neoplastic lymphocytes: implications for cancer therapy

摘要

Interleukin-2 (IL2) and IL15, members of the 4α-helix bundle family of cytokines, play pivotal roles in the control of the life and death of lymphocytes. Although their heterotrimeric receptors have two receptor subunits in common these two cytokines have contrasting roles in adaptive immune responses. The unique role of IL2 through maintenance of fitness of regulatory T cells (Treg) and activation-induced cell death (AICD) is the elimination of self-reactive T cells to prevent autoimmunity. In contrast to IL2, IL15 is dedicated to the prolonged maintenance of memory T-cell responses to invading pathogens. Blockade of IL2 and IL15 using monoclonal antibodies has been reported to be of value in the treatment of patients with leukemia, autoimmune disorders and in the prevention of allograft rejection. IL2 has been approved by the FDA for the treatment of patients with malignant renal cell cancer and metastatic malignant melanoma. Clinical trials involving recombinant human IL15 given by bolus infusions have been completed, and by subcutaneous and continuous intravenous infusions are underway in patients with metastatic malignancy. Furthermore, clinical trials are being initiated that employ the combination of IL15 with IL15Rα^+/− IgFc.