#phagocytes

True/False: Neutrophils are the first phagocytic cells to arrive at the site of invasion.

Show Your Teeth

Phagocytes are immune cells with a big appetite. They usually engulf whole pathogens, but this phagocyte has been fooled – placed over a glass plate loaded with tempting antibodies it stretches out over something it can never consume. This ‘frustrated’ phagocytosis allows researchers to peek at the molecular machinery involved, poking a microscope into the opening 'jaw' of a phagocyte. A technique called iPALM highlights its skeleton of tiny actin filaments that rearrange to form rings of pointy structures called podosomes – sometimes known as phagocytic teeth – used to latch onto targets at the beginning of phagocytosis. Rainbow colours highlight actin fibres at different depths, giving researchers hints to the 3D structure of podosomes, that future drug treatments may influence to improve the fight against disease-carrying pathogens.

Written by John Ankers

Image from work by J. Cody Herron, Shiqiong Hu and Takashi Watanabe, and colleagues

University of North Carolina at Chapel Hill, Chapel Hill, NC, USA

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Nature Communications, July 2022

my anatomy and physio class brought up microglia briefly and i just thought. what if they were in CaW and then i took it a step further and included them in my furry au <3

Gernot Kleinberger et al. The FTD‐like syndrome causing TREM2 T66M mutation impairs microglia function, brain perfusion, and glucose metabolism, The EMBO Journal (2017). DOI: 10.15252/embj.201796516

Phagocytes in the Brain: Good or Bad?

The role of microglial cells in neurodegenerative disease is not fully understood. But new results from researchers in Munich and Basel suggest that stimulation of this arm of the immune system might well delay the onset of such disorders.

Brain Defenders

Your bloodstream can carry any number of toxins and infections. That’s why your brain is protected from it by the blood-brain barrier, a tight seal allowing nutrients in but keeping potential threats out. However, it also keeps out the blood's immune cells. Thankfully, your brain has its own immune cells, perivascular macrophages (pvMs). These maintain the blood-brain barrier and are involved in immunity. Researchers take a closer look at these cells using mice genetically manipulated with fluorescent tags for macrophage markers. Through fluorescence microscopy of the brain (pictured), the team confirm the presence of a known population of macrophages with the marker Lyve1 (blue) around blood vessels (green, red) but also identify another population with the marker CX3CR1, which perform phagocytosis. What's more, after inducing a stroke in these mice, pvM numbers increased. These cells are, therefore, more diverse than originally thought and respond to the brain injury, stroke.

Written by Lux Fatimathas

Image from work by C. Siret and colleagues

Aix-Marseille Univ, CNRS, INSERM, Centre d’Immunologie de Marseille-Luminy (CIML), Marseille, France

Imageoriginally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Nature Communications, November 2022

The Scientific Research Notes of S. Sunkavally. Years: 1986 - 1990.