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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.
[49] [50] These molecules mark the cell for phagocytosis by cells that possess the appropriate receptors, such as macrophages. [51] The removal of dying cells by phagocytes occurs in an orderly manner without eliciting an inflammatory response and is an important function of phagocytes. [52]
The first demonstration of phagocytosis as a property of leukocytes, the immune cells, was from the German zoologist Ernst Haeckel. [14] [15] In 1846, English physician Thomas Wharton Jones had discovered that a group of leucocytes, which he called "granule-cell" (later renamed and identified as eosinophil [16]), could change shape, the phenomenon later called amoeboid movement.
Phagocytosis, also known as cell eating, is the absorption of larger particles such as bacteria into the cytosol. In smaller single-celled organisms, this is how it feeds. In larger multicellular organisms, it is a way of destroying old or damaged cells or ingesting microbial invaders.
Professional APCs specialize in presenting antigens to T cells. [5] They are very efficient at internalizing antigens, either by phagocytosis (e.g. macrophages), or by receptor-mediated endocytosis (B cells), processing the antigen into peptide fragments and then displaying those peptides (bound to a class II MHC molecule) on their membrane. [1]
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. [9] 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. A macrophage
Phagocytosis involves the internalization of solids, such as bacteria, by an organism. Phagocytosis in Three Steps. Macrophages, neutrophils, and dendritic cells are all cells of the innate immune system that utilize phagocytosis and are equipped with Toll-like receptors (TLR).
Phagocytosis is the process by which cells bind and internalize particulate matter larger than around 0.75 μm in diameter, such as small-sized dust particles, cell debris, microorganisms and apoptotic cells. These processes involve the uptake of larger membrane areas than clathrin-mediated endocytosis and caveolae pathway.