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==='''Promotion of phagocytosis'''===

==='''Promotion of phagocytosis'''===

Antibodies also have a function to facilitate [[Phagocytosis|phagocytosis]]. Phagocytes have receptors for the '''Fc''' portion of antibody, using '''Fc receptors (FcR)'''. FcR bind the Fc portion of antibody on antigen/antibody complexes, although the antibody alone does not interact with FcR. Interaction of FcR with Ab/Ag complexes stimulates '''cellular activation''' which greatly increases the efficiency of phagocytosis. This process is called '''opsonisation'''. Opsonisation promotes the '''production of intracellular enzymes''' and therefore promotes the killing and digestion of internalised micro-organisms. Systems used by phagocytes that are important in intracellular killing include free radicals such as oxygen and chlorine, hydrogen peroxidase and nitric oxide produced by nitric oxide synthase. Ultimately phagocytes undergo '''degranulation''' resulting in the '''secretion of certain enzymes and cytotoxic molecules'''. These systems are also activated by the interferons, especially the immune interferon – IFN & gamma. Antibody-mediated opsonisation of micro organisms is much more efficient that innate immune system receptors. Phagocytes also have receptors for iC3b, a [[Complement|complement]] component which is also a major initiator of opsonisation. Two particulary important phagocytic cells that have FcR are the [[Neutrophils|neutrophils]] and [[Macrophages|macrophages]].

Antibodies also have a function to facilitate [[Phagocytosis|phagocytosis]]. Phagocytes have receptors for the '''Fc''' portion of antibody, using '''Fc receptors (FcR)'''. FcR bind the Fc portion of antibody on antigen/antibody (Ag/Ab) complexes, although the antibody alone does not interact with FcR. Interaction of FcR with Ag/Ab complexes stimulates '''cellular activation''' which greatly increases the efficiency of phagocytosis. This process is called '''opsonisation'''. Opsonisation promotes the '''production of intracellular enzymes''' and therefore promotes the killing and digestion of internalised micro-organisms. Systems used by phagocytes that are important in intracellular killing include free radicals such as oxygen and chlorine, hydrogen peroxidase and nitric oxide produced by nitric oxide synthase. Ultimately phagocytes undergo '''degranulation''' resulting in the '''secretion of certain enzymes and cytotoxic molecules'''. These systems are also activated by the interferons, especially the immune interferon – IFN & gamma. Antibody-mediated opsonisation of micro organisms is much more efficient that innate immune system receptors. Phagocytes also have receptors for iC3b, a [[Complement|complement]] component which is also a major initiator of opsonisation. Two particulary important phagocytic cells that have FcR are the [[Neutrophils|neutrophils]] and [[Macrophages|macrophages]].

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