Immunity system complexity: controlling gut biome (Introduction)

by David Turell @, Wednesday, October 13, 2021, 18:51 (9 days ago) @ David Turell

IGA from gut immune cells control gut bacteria and keep them friendly:

"The bacteria living in the intestine consist of some 500 to 1000 different species. They make up what is known as the intestinal flora, which plays a key role in digestion and prevents infections. Unlike pathogens that invade from the outside, they are harmless and tolerated by the immune system. The way in which the human immune system manages to maintain this delicate balance in the intestine largely remains unknown. It is known that type A immunoglobulins, referred to as IgA antibodies, play an important role. These natural defense substances are part of the immune system, and recognize an exogenous pathogen very specifically according to the lock-and-key principle. (my bold)


"IgA antibodies are the most common antibodies in the human immune system, and are secreted by specialist cells in the mucous membranes. They account for two-thirds of human immunoglobulins. Surprisingly, most IgA antibodies produced by the body are directed against benign bacteria in the intestinal flora. Without this immune protection, these microorganisms could also have a detrimental effect on health and cause intestinal diseases. However, the mystery of the way in which IgA antibodies regulate the consensual coexistence in the intestine has remained unsolved.


"They succeeded in producing a sufficient amount of IgA antibodies specifically directed against a type of Escherichia coli bacteria, a typical intestinal bacterium. The antibodies recognized and bound a building block on the membrane of the microorganisms.


"The antibodies were found to affect the fitness of the bacteria in several ways. The mobility of bacteria was restricted, for example, or they hindered the uptake of sugar building blocks for the metabolism of the bacteria. The effect depended on the surface component that was specifically recognized. "This means that the immune system is apparently able to influence the benign intestinal bacteria through different approaches on a simultaneous basis", explains Hedda Wardemann of the German Cancer Research Center, co-author. The researchers therefore speak of IgA parallelism. (my bold)



"'our experiment shows that IgA antibodies can fine-tune the balance between the human organism and the intestinal flora,'"

Comment: read my bolds carefully. Bacteria let loose from the colon by a crack in the wall leads to severe peritonitis which kills quickly if not attacked by IV antibiotics. I read the word 'simultaneous' to indicate automaticity of the immune responses. Note the cells can quickly identify the gut bugs and handle them immediately. Newborns develop a gut biome immediately after birth with immediate inborn gut cell responses. No time to learn, just do it. This automaticity is medical text book teaching. The cells act intelligently because they are programmed that way. Sorry your pet theory doesn't fit this reality.

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