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Phagocytosis (from Ancient Greek φαγεῖν (phagein) 'to eat' and κύτος (kytos) 'cell') is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte.
This cytokine—a class of signaling molecule [39] —kills cancer cells and cells infected by viruses, and helps to activate the other cells of the immune system. [ 40 ] In some diseases, e.g., the rare chronic granulomatous disease , the efficiency of phagocytes is impaired, and recurrent bacterial infections are a problem. [ 41 ]
Signal Recognition: The process begins with the exposure of a signal on the target particle or cell. This signal, often referred to as an "eat-me" signal, is recognized by receptors on the surface of the phagocyte. [9] The phagocyte then engulfs the extracellular pathogen or particle, entrapping it within its membrane.
Due to their role in phagocytosis, macrophages are involved in many diseases of the immune system. For example, they participate in the formation of granulomas, inflammatory lesions that may be caused by a large number of diseases. Some disorders, mostly rare, of ineffective phagocytosis and macrophage function have been described, for example ...
Other non-professional phagocytes have some degree of phagocytic activity, such as thyroid and bladder epithelial cells that can engulf erythrocytes and retinal epithelial cells that internalise retinal rods. [8] However non-professional phagocytes do not express specific phagocytic receptors such as FcR and have a much lower rate of ...
In immunology, the mononuclear phagocyte system or mononuclear phagocytic system (MPS) also known as the macrophage system is a part of the immune system that consists of the phagocytic cells [1] located in reticular connective tissue. The cells are primarily monocytes and macrophages, and they accumulate in lymph nodes and the spleen.
NK cells also kill tumorous cells in a similar way, especially if the tumor cells have fewer MHC class I molecules on their surface than normal; this is a common phenomenon with tumors. [144] Sometimes antibodies are generated against tumor cells allowing for their destruction by the complement system. [139]
The phagocytes interact with the dying cells through the presenting eat-me signals through specific eat-me signal receptors on the phagocytic cell. [23] The phagocyte will engulf the eat-me signal presenting cell through induced signaling of engulfment receptors and by the reorganization of the phagocytic cell's cytoskeleton. [24] The ...