(Medical Xpress) -- Adult brains generate thousands of new brain cells called neurons each day; however only a small fraction of them survive. The rest die and are consumed by scavenger cells called phagocytes. Until now, ...
Aug 10, 2011
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Scientists at the University of Sheffield have identified a protein which causes cells to eat their dying neighbours, helping to prevent inflammation - something which is vital in the fight to stop cancer spreading.
Sep 12, 2016
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(Medical Xpress)—Membrane fusion is a highly regulated event, both inside cells, and between them. From the moment a sperm first fuses with an egg, subsequent developmental events depend upon its proper control. Inside ...
(Medical Xpress) -- Researchers at the University of Illinois at Chicago College of Medicine have found in an animal model of acute lung injury a molecular mechanism that allows cells of the immune system to reduce tissue ...
Dec 14, 2011
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(HealthDay)—The cytokine M-CSF promotes survival of lung and liver mononuclear phagocytes to mediate host defense during bacterial pneumonia, according to an experimental study published in the June 15 issue of The Journal ...
Aug 4, 2016
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UCI scholars Zachary W. Wagoner, a graduate student researcher in cellular & molecular biosciences, and Weian Zhao, professor of pharmaceutical sciences, have identified a new mechanism by which transplanted stem cells treat ...
May 18, 2021
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The natural life cycle of cells that line the intestine is critical to preserving stable conditions in the gut, according to new research led by a Weill Cornell Medicine investigator. The findings may lead to the development ...
Mar 1, 2017
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Seasonal epidemics of influenza result in nearly 36,000 deaths annually in the United States, according to the Centers for Disease Control. Current vaccines against the influenza virus elicit an antibody response specific ...
Mar 14, 2013
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(Medical Xpress)—A team of Canadian researchers has found that platelets in mice liver collaborate with special types of white blood cells to help capture bacteria. In their paper published in the journal Nature Immunology, ...
Mononuclear phagocytes can both promote and inhibit inflammation. An LMU team has now shown that individual phagocytes in the central nervous system can play both roles, sequentially adopting different phenotypes with distinct ...
Sep 11, 2018
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Phagocytes are the white blood cells that protect the body by ingesting (phagocytosing) harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek phagein, "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek kutos, "hollow vessel". They are essential for fighting infections and for subsequent immunity. Phagocytes are important throughout the animal kingdom and are highly developed within vertebrates. One litre of human blood contains about six billion phagocytes. Phagocytes were first discovered in 1882 by Ilya Ilyich Mechnikov while he was studying starfish larvae. Mechnikov was awarded the 1908 Nobel Prize in Physiology or Medicine for his discovery. Phagocytes occur in many species; some amoebae behave like macrophage phagocytes, which suggests that phagocytes appeared early in the evolution of life.
Phagocytes of humans and other animals are called "professional" or "non-professional" depending on how effective they are at phagocytosis. The professional phagocytes include cells called neutrophils, monocytes, macrophages, dendritic cells, and mast cells. The main difference between professional and non-professional phagocytes is that the professional phagocytes have molecules called receptors on their surfaces that can detect harmful objects, such as bacteria, that are not normally found in the body. Phagocytes are crucial in fighting infections, as well as in maintaining healthy tissues by removing dead and dying cells that have reached the end of their lifespan.
During an infection, chemical signals attract phagocytes to places where the pathogen has invaded the body. These chemicals may come from bacteria or from other phagocytes already present. The phagocytes move by a method called chemotaxis. When phagocytes come into contact with bacteria, the receptors on the phagocyte's surface will bind to them. This binding will lead to the engulfing of the bacteria by the phagocyte. Some phagocytes kill the ingested pathogen with oxidants and nitric oxide. After phagocytosis, macrophages and dendritic cells can also participate in antigen presentation, a process in which a phagocyte moves parts of the ingested material back to its surface. This material is then displayed to other cells of the immune system. Some phagocytes then travel to the body's lymph nodes and display the material to white blood cells called lymphocytes. This process is important in building immunity. However, many pathogens have evolved methods to evade attacks by phagocytes.
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