How does the brain protect itself? A protective barrier around the blood vessels prevents all but the smallest of molecules from invading. This keeps pathogens out but elements of the immune system too. The brain compensates for this shortage with its own long, branched immune cells (above) whose ‘fingers’ continuously monitor the surroundings. Should these cells encounter an unusual signal, perhaps from an ailing brain cell, invading pathogen or broken blood vessel, they morph to become rounded and mobile. When they reach the problem they change again, this time into a cell that can engulf and destroy foreign material. Here, using cell culture and 3D modelling, researchers demonstrate these super-immune cells are derived not from the brain but from a primitive blood cell. This goes some way to explain why they are similar to several other regular immune cells.
Written by Julie Webb
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