Immunity complexity: the gut produces brain protections (Introduction)

by David Turell , Wednesday, November 04, 2020, 22:53 (1271 days ago) @ David Turell

It makes antibodies to protect the brain:

https://cosmosmagazine.com/health/body-and-mind/how-the-gut-protects-the-brain/?utm_sou...

"The gut is well known for being the first line of defence against infection, but it seems it also protects our most important organ – the brain.

"According to surprising new research, antibodies that defend the perimeter of the brain are normally found in, and trained by, our gut.

“'This finding opens a new area of neuroimmunology, showing that gut-educated antibody-producing cells inhabit and defend regions that surround the central nervous system,” says Dorian McGavern from the National Institutes of Health, US, co-author of a paper in the journal Nature.

“'This finding was completely unexpected,” says McGavern. “Prior to our study, IgA cells had not been shown to reside in the dura mater – the outer meninge – under steady state conditions.”

"The researchers first found these cells in mice then confirmed that IgA was also present in human cells they collected from the meninges during surgery.

"They used DNA sequencing to identify the origin of these IgA cells and found that, out of millions of IgA sequences, they most closely matched a very specific gut IgA that occurred in the intestine.

"Understandably, the gut microbiome helps gut IgA learn to defend against infections that may enter our stomach and intestine, but these two IgA share an origin, which means brain IgA cells share the same training ground.

“'It’s truly remarkable that in such a small piece of intestine we would see this large an overlap with cells in the meninges,” McGavern says. “These data provide more compelling evidence that the brain is protected by immune cells that are educated in the gut.”

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“'But actually, it makes perfect sense: even a minor breach of the intestinal barrier will allow bugs to enter the bloodstream, with devastating consequences if they’re able to spread into the brain,” says Cambridge’s Menna Clatworthy.

“'Seeding the meninges with antibody-producing cells that are selected to recognise gut microbes ensures defence against the most likely invaders.'”

Comment: The bold is the key to understanding why it is set up like this. It is great design planning since the stomach and gut are the necessary entry into our bodies.