Gut infections establish long-lasting immune memory in the brain of mice

A study published in Nature Neuroscience reveals that intestinal infections can create long-lasting immune memories at the borders of the brain in mice. Researchers discovered that when mice experience gastrointestinal challenges from bacterial pathogens, antigen-specific, long-lived memory CD4+ helper T cells migrate from the gut to the dura mater, the outermost meningeal layer surrounding the brain.

These gut-derived immune cells contribute to recall immune responses that reduce the spread of pathogens to the brain. This occurs even if the subsequent challenge involves a different pathogen in models using shared antigens. The findings highlight a significant communication route between gut immunity and the central nervous system (CNS), suggesting that oral priming can help protect the brain from circulating microorganisms that might otherwise enter via the brain’s venous drainage system.