- Antibody-dependent cell-mediated cytotoxicity
Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) is a mechanism of cell-mediated immunity whereby an effector cell of the
immune systemactively lyses a target cell that has been bound by specific antibodies. It is one of the mechanisms through which antibodies, as part of the humoral immune response, can act to limit and contain infection. Classical ADCC is mediated by natural killer (NK) cells; monocytesand eosinophils can also mediate ADCC. For example Eosinophilscan kill certain parasitic worms known as helminths through ADCC. ADCC is part of the adaptive immune response due to its dependence on a prior antibody response.
ADCC by NK cells
The typical ADCC involves activation of NK cells by antibodies. An NK cell's Fc receptor recognizes the Fc portion of an
antibody, such as IgG, which has bound to the surface of a pathogen-infected target cell. The most common Fc receptor on the surface of an NK Cell is called CD16or FcγRIII. Once bound to the Fc receptor of IgG, the Natural Killer cell releases cytokinessuch as IFN-γ, and cytotoxic granules containing perforinand granzymesthat enter the target cell and promote cell death by triggering apoptosis. This is similar to, but independent of, responses by cytotoxic T cells (CTLs).
ADCC by eosinophils
parasites like helminths are too big to be engulfed and killed by phagocytosis. They also have an external structure or integumentthat is resistant to attack by substances released by neutrophils and macrophages. However, an antibody called IgEcan coat these parasites. The Fc receptor(FceRI) of an eosinophilcan then recognize IgE. The interaction between FceRI and the Fc portion of helminth-bound IgE causes the eosniophil to degranulate.
*cite book | author = Janeway CA, Jr. "et al" | title = Immunobiology. | edition = 5th ed. | publisher = Garland Publishing | year = 2001 | id = [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowTOC&rid=imm.TOC&depth=10 (electronic full text via NCBI Bookshelf)] ISBN 0-8153-3642-X
*cite book | author = Pier GB, Lyczak JB, Wetzler LM | title = Immunology, Infection, and Immunity | edition = | publisher = ASM Press| year = 2004 | id = ISBN 1-55581-246-5
* [http://www-micro.msb.le.ac.uk/3035/3035Immunopath.html University of Leicester] , Virus Immunopathology Notes
Wikimedia Foundation. 2010.
Look at other dictionaries:
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