Immune Cells Trained by the Gut To Protect the Brain

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immune cells found in the meninges are trained in the gut

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In the inside of our heads, battles are consecutively occurring. A press release by the U.S. National Institute of Neurological Disorders and Stroke (NINDS) said that the membranes surrounding our brains are in a never-ending battle against deadly infections, as germs constantly make their way and try to flee from watchful immune cells and sneak past a special protective barrier that is called meninges.

Researchers from the National Institutes of Health and Cambridge University presented that some of the immune cells fighting in the membranes are trained to fight the infections by spending time in the gut. Based on investigating what kind of antibodies were produced by plasma cells in the meninges led to a discovery of a type of antibodies called Immunoglobulin A (IgA), which are generally produced either in the gut and mucosal lining of the lungs and nose.

Co-senior author of the study, and senior investigator at National Institute of Neurological Disorders (NINDS), Dorian McGavern, Ph.D., said in a statement that the findings of the study open a new area of neuroimmunology showing that antibody-producing cells educated by the gut inhabit and defend regions that surround the central nervous system.

According to NIH, the central nervous system (CNS) is protected from pathogens both by a three-membrane barrier called the meninges and immune cells. They added that CNS is walled off from the rest of the body utilizing specialized blood vessels that are tightly sealed with the blood-brain barrier.

Menna Clatworthy from the University of Cambridge said that it is quite a surprise the important line of defense the brain uses to protect itself from infection is quite surprising. According to NIH, when the researchers compared DNA sequences of IgA cells found in the meninges to those from the intestine's short segments, the researchers found out that more than 20 percent overlap between the two. According to D. McGavern, this implies that the brain is safeguarded by immune cells educated in the gut.

Evidence

According to the researchers, several follow-up experiments using a mouse as models affirmed the strong gut-brain relationship when they raised mice with no gut bacteria allowing them to discover that there is no IgA producing cells in the meninges of their brain, leading them to a hypothesis that the role of specific immune cells is to protect the brain from destroying gut microbes that can enter the bloodstream. Clatworthy said that a minor breach of the intestinal barrier would allow bugs to enter the bloodstream and cause serious trouble to the brain. She added that the antibody-producing cells present in the meninges would make the defense stronger because they will recognize the gut microbes, ensuring the invaders' defense.

Implication

According to the researchers, the tissue removed during the routine surgeries validated the animal findings, confirming the gut-brain relationship is vital in helping the body battle specifically in the Central nervous system infections such as meningitis.

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