What are Peyer's PLATES and their function
Our immune system It is made up of primary organs, where immune cells, such as the bone marrow and thymus, are generated and matured, and of secondary organs, where the immune response takes place against antigens, such as the spleen, lymph nodes, or mucosa-associated lymphoid tissue (MALT). In this article by a PROFESSOR we will talk about this fabric and what are Peyer's patches and their function. If you want to find out more about them, read us in the next article!
Index
- What are Peyer's patches
- Characteristics of Peyer's patches
- Function of Peyer's patches
What are Peyer's patches.
The immune response in our body It is mediated by different types of cells, some with a more nonspecific response and others more specific for a certain antigen. In this more specific response in the recognition of antigens, the most important are the lymphocytes.
Peyer's patches are regions that are located under the mucosa of the gastrointestinal tract, specifically in the lamina propria (loose connective tissue) of the small intestine. As with lymphoid follicles in the submucosa of the appendix or in the tonsils of the pharynx, Peyer's patches
look like lymph nodes in their function, with the great difference that they are neither encapsulated nor as organized as these.Peyer's patches were first described in 1645 as "lymphoid clusters or follicles" by the Italian physician Marco Aurelio Severino. However, it was not until 1677 when the term Peyer's patches was adopted to name these structures, due to the Swiss pathologist who made a more detailed description of these structures, Conrad Peyer.
However, although its structure was known, its function remained unknown until 1922, when Kenzaburo Kumagai described its capacity in the absorption of pathogenic and foreign cells through the epithelium of Peyer's patches.
Image: Tucuerpohumano.com
Characteristics of Peyer's patches.
Unlike other encapsulated organs where the immune response compared to antigens, such as the spleen or lymph nodes, the mucosa-associated lymphoid tissue (MALT) is not an organ as such, but are accumulations of non-encapsulated lymphoid tissue in different locations in the body, such as the bronchi (BALT), associated with the nose (NALT), the genitourinary tract or the intestine (GALT). In this last group (GALT) are known as Peyer's patches.
Peyer's patches are made up of lymphoid follicles (aggregate or set of lymphoid cells without a defined structure or a particular organization) distributed throughout the entire gastrointestinal tract, mainly grouped in the final portion of the small intestine (the ileum), and represents one of the largest lymphoid ‘organs’ in the body, since in it they are almost 70% of immune cells.
Peyer's patches adopt an almost oval structure and irregularly distributed. There is no consensus on the area occupied and the number of these plaques that are distributed in the intestine, but it is believed that most are concentrated in the last 25 cm of the ileum and reach their maximum peak between the second and third decade of the life.
Like other body tissues, the organogenesis of these plaques depends on specific cytokines (small molecules released by different cells in the body) that mediate the differentiation of these regions of the body.
Function of Peyer's patches.
The main function of Peyer's patches is to serve as an immune system to the mucosa of the intestine and protect it from invasions of microorganisms and potentially dangerous substances.
The cells of the lymphoid follicles of Peyer's patches also serve to discriminate between pathogens and commensals (those that are part of the normal microbiota of the intestine and that play a role in helping the digestion and immune defense), since these microorganisms interact directly with the epithelium intestinal.
By participating also in the absorption of foreign or pathogenic cells, the Peyer's patches belonging to this region are also capable of differentiate between certain potentially dangerous antigens and non-pathogenic bacteria associated with the intestine.
The process by which nonpathogenic antigens are recognized and tolerated is called oral tolerance and it is a process that requires the formation of T lymphocytes with the ability to recognize and tolerate these antigens and thus prevent an unnecessary immune response that could be harmful to the body. Therefore, oral tolerance is defined as the impediment in the production of cellular and humoral immune responses towards Specific antigens that arrive orally and are a very useful mechanism to avoid immune reactions unfavorable.
These mechanisms of oral tolerance fthey also unite with food, since these are also substances foreign to our body and the immune system is prepared to respond to substances foreign to us. However, these mechanisms sometimes fail and hypersensitivity reactions or food allergies can occur that can be very serious.
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Bibliography
- Ramiro-Puig, E., Pérez-Cano, F. J., Castellote, C., Franch, A., & Castell, M. (2008). The intestine: a key part of the immune system. Spanish Journal of Digestive Diseases, 100 (1), 29-34.
- Roux, M. E., López, M. C., Melton, E., Slobodianik, N. H., Gonzålez Ariki, S., & Garcia, P. (1989). Lymphoid system and protein deficiency. Differentiation in thymus and Peyer's patches. Medicine (Buenos Aires), 49, 162-165.
- Roca, V., Manchego, A., Sandoval, N., Chiok, K. L., & Rivera, H. (2014). Histological characterization and lymphoid dynamics of Peyer's patches in baby alpaca during the first 45 days of life. Journal of Veterinary Research of Peru, 25 (3), 341-349.
