IL-15 enhanced antibody-dependent cellular cytotoxicity mediated by NK cells and macrophages

Abstract

Previously we demonstrated that IL-15 by continuous infusion at 2 μg/kg/d for 10 days induced a 38-fold increase in circulating natural killer (NK) cells and a 358-fold increase in CD56 bright NK cells. In the present study we demonstrated that IL-15 enhanced antibody-dependent cellular cytotoxicity (ADCC) of tumor-directed monoclonal antibodies in two systems. Both NK cells and macrophages were required for optimal therapeutic responses. These studies support clinical trials of IL-15 combined with tumor-directed monoclonal antibodies. In translation of this study, a phase I trial of IL-15 combined with alemtuzumab has been opened for patients with adult T cell leukemia (ATL) NCT02689453.