Antibody-Dependent Phagocytosis of Tumor Cells by Macrophages: A Potent Effector Mechanism of Monoclonal Antibody Therapy of Cancer

Nowadays, it is impossible to imagine modern cancer treatment without targeted therapies, such as mAbs, that bind to tumor-associated antigens. Subsequently, mAbs can use a wide range of effector functions that mostly engage the immune system. mAbs can bridge immune effector cells with tumor cells, which can result in antibody-dependent cytotoxicity. Increasing evidence, however, identified macrophages as prominent effector cells and induction of antibody-dependent cell phagocytosis as one of the primary mechanisms of action mediated by mAbs. Macrophages are extremely effective in eliminating tumor cells from the circulation. Several immunosuppressive mechanisms may, however, hamper their function, particularly in solid malignancies. In this review, we discuss the evolving insight of macrophages as effector cells in mAb therapy and address novel (co)therapeutic strategies that may be used to fully unleash their cytotoxic capacity for the treatment of cancer.