Innate immune system: Difference between revisions

Revision as of 03:56, 12 October 2023

Revision as of 15:23, 29 November 2023

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The word 'phagocyte' literally means 'eating cell'. These are immune cells that engulf, or '[[Phagocytosis|phagocytose]]', pathogens or particles. To engulf a particle or pathogen, a phagocyte extends portions of its [[plasma membrane]], wrapping the membrane around the particle until it is enveloped (i.e., the particle is now inside the cell). Once inside the cell, the invading pathogen is contained inside a [[phagosome]], which merges with a [[lysosome]].<ref name="Janeway"/> The lysosome contains enzymes and acids that kill and digest the particle or organism. In general, phagocytes patrol the body searching for pathogens, but are also able to react to a group of highly specialized molecular signals produced by other cells, called [[cytokines]]. The phagocytic cells of the immune system include macrophages, [[neutrophils]], and dendritic cells.

Phagocytosis of the hosts’hosts' own cells is common as part of regular tissue development and maintenance. When host cells die, either by [[apoptosis]] or by cell injury due to an infection, phagocytic cells are responsible for their removal from the affected site.<ref name=Alberts/> By helping to remove dead cells preceding growth and development of new healthy cells, phagocytosis is an important part of the healing process following tissue injury. [[File:Macrophage.jpg|thumb|left|150px|A macrophage]]

====Macrophages====