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| | ==[[Recognition of Microorganisms]]== | | ==[[Recognition of Microorganisms]]== |
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| − | ==Phagocytosis== | + | ==[[Phagocytosis]]== |
| − | * Phagocytosis is a very primitive system of defence against infection
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| − | ** Even exists in invertebrates
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| − | * Phagocytosis is a form of endocytosis (cell eating), it is the method of removal of bacteria and dead cells by vesicular internalisation
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| − | ** The internalised vesicle is referred to as the "phagosome"
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| − | ** '''Lysosomes''', which contain a large range of enzymes, fuse with the phagosome, killing the microbes in an energy-dependent way
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| − | *** Oxygen-dependant degradation utilizes Oxygen and chlorine free-radicals, Hydrogen peroxide, and Nitric oxide
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| − | *** Oxygen-independant degradation depends on granules containing proteolytic enzymes such as Defensins, Lysozyme, and cationic proteins
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| − | **** In addition, these granules contain antimicrobial elements such as lactoferrin
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| − | ** Microbes are then digested by a number of different catabolic enzymes
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| − | *** Glycosidases: Digest carbohydrates
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| − | *** Lipases: Digest lipids
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| − | *** Proteases: Digest protein
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| − | ** Waste products of phagocytosis are either exocytosed or further degraded by the phagocyte
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| − | * '''Neutrophils''' and '''macrophages''' are phagocytic
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| − | * '''Opsonins''' promote and accelerate phagocytosis
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| − | * Phagocytic cells target pathogens by using cell membrane receptors (PRRs) that recognise intrinsically foreign components of microorganisms (pathogen-associated molecular patterns; PAMPs)
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| − | Video of phagocytosis of ''Candida albicans'': [http://www.cellsalive.com/qtmovs/mac_mov.htm]
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| | =Tools of Innate Immunity= | | =Tools of Innate Immunity= |