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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.
Unbound phagocyte surface receptors do not trigger phagocytosis. 2. Binding of receptors causes them to cluster. 3. Phagocytosis is triggered and the particle is taken up by the phagocyte. Phagocytosis is the process of taking in particles such as bacteria, invasive fungi, parasites, dead host cells, and cellular and foreign debris by a cell. [22]
Thus, phagocytosis is not a randomly occurring event. It is triggered by a ligand binding to a receptor. Some cells are specially designed to phagocytize. These cells include Natural Killer cells, macrophages, and neutrophils. All of these are involved in the immune response and serve to degrade foreign or antigenic material [4]
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.
Phagocytosis of a bacterium, showing the formation of phagosome and phagolysosome 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).
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 ...
Opsonins induce phagocytosis of targets by binding the targets (e.g. bacteria) and then also binding phagocytic receptors on phagocytes. Thus, opsonins act as bridging molecules between the target and the phagocyte, bringing them into contact, and then usually activating the phagocytic receptor to induce engulfment of the target by the phagocyte.
Cellular immunity, also known as cell-mediated immunity, is an immune response that does not rely on the production of antibodies. Rather, cell-mediated immunity is the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.