تسجيل الدخول

تسجيل

Antibody-Dependent Cell-Mediated Cytotoxicity

المؤلف:  Abbas, A. K., Lichtman, A. H., Pillai, S., & Henrickson, S. E.

المصدر:  Cellular and Molecular Immunology (2026)

الجزء والصفحة:  11E, P300

2026-09-06

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Natural killer (NK) cells and other leukocytes bind to antibody coated cells by Fc receptors and destroy these cells. This process is called antibody-dependent cell-mediated cytotoxicity (ADCC) (Fig. 1). It was first described as a function of NK cells, which use their Fc receptor, FcγRIIIA (CD16), to bind to antibody-coated cells. FcγRIIIA is a low-affinity receptor that binds clustered IgG molecules displayed on cell surfaces but does not bind circulating monomeric IgG. Therefore, ADCC occurs only when the target cell is coated with antibody molecules, and free IgG in plasma neither activates NK cells nor competes effectively with cell-bound IgG for binding to FcγRIII. The engagement of FcγRIIIA by antibody coated target cells activates the NK cells to synthesize and secrete cytokines, such as IFN-γ, and to discharge the contents of their granules, which mediate the killing functions of this cell type. ADCC can also be mediated by macrophages.

Fig1. Antibody-dependent cell-mediated cytotoxicity. Antibodies of certain immunoglobulin G (IgG) subclasses bind to cells (e.g., infected cells), and the Fc regions of the bound antibodies are recognized by an Fcγ receptor on natural killer (NK) cells. The NK cells are activated and kill the antibody-coated cells.

ADCC activity may be relevant to immunity directed at enveloped viruses since envelope/spike proteins can decorate infected cells. Correlations have been shown between ADCC activity and the reduction of viremia by vaccines and some therapeutic monoclonal antibodies. ADCC also may be a mechanism for the elimination of cells that are coated by certain therapeutic monoclonal antibodies, such as B cells and B cell–derived tumor cells that are targeted by monoclonal anti CD20 antibodies.