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Microbiology General d67d10e5

Which is the main cell involved in antibody-dependent cell-mediated cytotoxicity (ADCC)?

A
Natural killer cells
B
CD 4+ T cells
C
Cytotoxic T lymphocytes
D
B lymphocytes
High-Yield Explanation
NK cells bind to antibody-coated cells by Fc receptors and destroy these cells. This process is called antibody-dependent cell-mediated cytotoxicity (ADCC). It was first described as a function of NK cells, which use their Fc receptor, FcgRIII, to bind to antibody-coated cells. FcgRIII/CD16 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. Engagement of FcgRIII by antibody-coated target cells activates the NK cells to synthesize and secrete cytokines such as IFN-g as well as to discharge the contents of their granules, which mediate the killing functions of this cell type. NK cells are the major cell type that carries out antibody-dependent cellular cytotoxicity (ADCC). ADCC can also be carried out by other cells that express Fc receptors and have the machinery to kill targets. Thus neutrophils,eosinophils, monocytes, and macrophages also carry out ADCC, although they use different effector molecules than NK cells.

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