Uniqueness of Mucosal Immunity System – M cells and Peyer’s Pathces

So let me tell you about the importance of mucosal immunity including mammary gland immunity or intestinal immunities. This is one model of intestinal immunity because my major is mucosa immunity. Of course, you guys every day eat food, like meat or fish but simultaneously several microorganisms, not only pathogenic bacteria but also beneficial bacteria are infiltrated into the tissues in the gastrointestinal tract. Some of the bacteria are pathogenic. That’s why if you don’t have any immune system in the gastrointestinal tract, of course, you cause diseases like diarrhea. But of course, you don’t cause diseases such as diarrhea very often because you have immunity in your gastrointestinal tract that is mucosal immunity.

So understanding the mucosal immune system is very important in order to control the mucosal infectious diseases. This slide shows you how IgA antibodies are produced in the gastrointestinal tract in the gut immune system. Because the gut immune system has been well studied in the mucosa immunity. In the gastrointestinal tract, there are two distinct tissue structures. One is inductive tissues

and the other is effector tissues.

Inductive tissue contains a large number of mature naive B cells and some of them are stimulated by antigens. Because in the inductive site, in the exterior layers, there are very specialized unique cells named M cells. And M cells take up to numeral antigens in order to stimulate B cells which are mostly naive B cells. And then after antigens stimulations B cells start to move to the effector tissues, such as lamina propria then they start to produce IgA antibodies. And these IgA antibodies are very important to establish a symbiotic relationship between the host and microorganisms.

The inductive tissues of intestinal tissues so we have known that the Peyer’s patches that is the name of the inductive tissues in the small distance is well studied. So if you see the structures of the inductive tissues, that is Peyer’s patches, that Doctor Peyer identified the structures in almost 17 centuries.