Researchers at the Institute for Basic Science record how a regular balanced diet provides immune tolerance conditions in the small intestine.

Our immune system evolved to attack foreign materials entering our body. Food is technically foreign, but it is somehow tolerated by the immune system so that our body can absorb the nutrients. The immune system has built-in tolerance mechanisms that harness itself from responding to benign foreign antigens beneficial to our system, like food. When such tolerance fails, we suffer from an overt immune reaction, such as food allergies, which can be severe enough to be fatal. Despite the increasing incidence and severity of food allergies, the details on how immune tolerance to dietary antigens is normally established remain largely unknown. Scientists from the Academy of Immunology and Microbiology (AIM) within IBS in South Korea have recently uncovered one of the key mechanisms in the small intestine that triggers this process.

A key mechanism used by our body to induce immune tolerance is by induction of regulatory T (Treg) cells, a subset of white blood cell that orders other T cells to stand down. In the gut, a special subset of Treg cells, called peripheral Treg (pTreg) cells, exists in both the small and large intestine. Previous research showed that pTreg cells are created in the large intestine in response to the normal commensal intestinal bacteria, which play a vital symbiotic role in our health. pTreg cells were also believed to exist in the small intestine to inform the immune system on which food antigens can enter our body. The IBS research team has now discovered that normal diet does indeed induce the creation of the pTreg cells in the small intestine.

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