Why human immunity does not reject food

As you know, our body constantly fights cells that it considers foreign. So why after

After eating food, a person does not have an immune response if we just “let” foreign cells into ourselves. Scientists from the University of Minnesota Medical School answered this question. Discuss

A new study has shown that foreign proteins in food provoke the formation of regulatory immune cells that suppress serious inflammatory responses.

To prove such tolerance of the immunesystems to food, experts conducted tests with mice that grew up on a gluten-free diet. Subsequently, they were given different foods, including foods with one or more types of gluten proteins (gliadins), and analyzed for subsequent immune responses. It is known that people with dietary celiac disease have gluten intolerance precisely because of a defective immune response.

For most people, daily consumptionforeign plant and animal proteins does not lead to the development of a T-cell immune response. However, the same reactions still occur in the body that cause an immune response against the proteins of viruses and bacteria. Dietary proteins are presented by major histocompatibility complex class II (MHCII) to CD4+ T cells, which normally recognize foreign molecules for future pathogen attack. “In the fight against infection, T cells provoke an inflammatory response, which is absent in the case of dietary proteins.”

It turned out that in rodents after gliadinthere was only a slight increase in the number of protein-specific T cells in the lymphoid organs of the gastrointestinal tract. The proliferation of pro-inflammatory CD4+ cells was suppressed by a different type of immune cell known as “regulatory Treg cells”. Some of the gliadin-specific T cells then turned into follicular helper T cells, which elicited a weak antibody response. At the same time, a full-fledged immune response did not develop, since many T cells that could multiply turned out to be “non-canonical”, that is, unable to cause inflammation, eventually turning into Treg.

Exposure of dietary antigens to naive T cellsleads to the development of subpopulations of T cells that are unable to cause inflammatory functions and at the same time produce T cells that suppress inflammation, the scientists concluded.