User:Charlmane/sandbox
From Wikipedia, the free encyclopedia
In cell biology, a phagosome is a vesicle formed around a particle engulfed by a phagocyte via phagocytosis. Professional phagocytes include macrophages, neutrophils, and dendritic cells (DCs). A phagosome is formed by the fusion of the cell membrane around a microorganism or senescent cell. Phagosomes have membrane-bound proteins to recruit and fuse with lysosomes to form mature phagolysosomes. They contain hydrolytic enzymes and reactive oxygen species (ROS) which kill and digest the pathogens. Phagosomes can also form in non-professional phagocytes, but they can only engulf a smaller range of particles, and do not contain ROS. The useful materials (e.g. amino acids) from the digested particles are moved into the cytosol, and waste is removed by exocytosis. Phagosome formation is crucial for tissue homeostasis and both innate and adaptive host defense against pathogens.
![]() | This is the user sandbox of Charlmane. A user sandbox is a subpage of the user's user page. It serves as a testing spot and page development space for the user and is not an encyclopedia article. Create or edit your own sandbox here. Other sandboxes: Main sandbox | Template sandbox Finished writing a draft article? Are you ready to request review of it by an experienced editor for possible inclusion in Wikipedia? Submit your draft for review! |
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/Phagocytosis2.png/640px-Phagocytosis2.png)
However, some bacteria can exploit phagocytosis as an invasion strategy. They either reproduce inside of the phagolysosome (e.g. Coxiella spp.)[1] or escape into the cytoplasm before the phagosome fuses with the lysosome (e.g. Rickettsia spp.)[2]. Many Mycobacteria, including Mycobacterium tuberculosis [3] [4] and Mycobacterium avium paratuberculosis [5], can manipulate the host macrophage to prevent lysosomes from fusing with phagosomes and creating mature phagolysosomes. Such incomplete maturation of the phagosome maintains an environment favorable to the pathogens inside it [6].