All Glia

Forming a barrier around the brain and central nervous system – the glia limitans (a thin layer of processes emanating from cells called astrocytes) is a bit like a moat around a castle, although ~100,000 times smaller. It protects the nervous system, yet must allow immune cells safe passage in times of infection. How this happens – known as immune privilege – is still a little mysterious. Here we see the glia limitans (highlighted in red) around part of the spinal cord of a living mouse. The genetically-modified mouse carries an altered gene that gives red fluorescence to the glia limitans. Researchers captured this video using intravital microscopy, also revealing fluorescent particles highlighting its blood vessels (green). The team hopes that similar transgenic mice will help researchers probe deeper into the glia limitans, and links between the nervous systems and immunity in health and disease.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

Website

• Video from work by Pauline Hélie-Legoupil and Florencia Kloster, and colleagues
• Theodor Kocher Institute, University of Bern, Bern, Switzerland
• Video originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Nature Communications, October 2025