The role of the gastrointestinal tract

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According to numerous reports [62-68], Mature gastrointestinal tract has a protective mechanisms, preventing the penetration of antigens. However, the mucous membrane of the intestine, especially in children of early age is not an insurmountable barrier.
Penetration antigens through the intestinal mucosa occurs, apparently, in several stages (Fig. 2). Macromolecule adsorbed on the microvilli membrane and invalidinput it (endocytosis); they are prisoners in small vacuoles due to volatile movements. Formed vacuoles move from the surface to the center of the cell and merge to form a larger vacuoles (vagotomy). Intracellular complementary mechanism to absorb vagotomy, resulting in the formation of an even larger vacuoles (phagolysosome), in which the absorption of particles. The remaining undigested particles enclosed in small vacuoles, move to the basal surface of cells that are released from vacuoles (exocytosis) and deposited in the intercellular space. The more molecules pass through the epithelial cell intestine, the more likely they enter the lymphatic system and blood. The factors, which increase absorption of macromolecules are incomplete their assimilation within cells, a violation of the mucous membrane of the intestines and the reduction of the amount of IgA [70]. In experiments on rats found that the absorption of intact protein in the small intestine is much more intensive than in the colon [67]. The intestinal wall rich lymphoid tissue, concentrated mainly in Meyerovich plaques and diffuse scattered throughout stroma. Stroma cells produce immunoglobulins all classes, but most of all IgA [62, 63, 66].
Apparently, the immune system prevents absorption of macromolecules at the level of cells and is involved in the neutralization of molecules antigens in case of their penetration into blood. Specific antibodies that are formed for a particular antigen can be detected in the secret of intestines, or in Calais (coproantigen) [71-74].
In the examination of children under the age of 2 years with gastrointestinal Allergy to cow's milk Kletter et al. [75] found using the method of radioimmunoconjugates that coproantigen to milk proteins are mainly in the IgA class, and only partly to IgG class. Meanwhile, the ratio of IgA and IgG in blood was the opposite; in addition, antibody levels in Calais and serum correlated among themselves. These data suggest that local immune response in the intestine does not depend on systemic reactions. The hypothesis is confirmed by the data Ogra and Karzon [73]who examined children after they produced double-barreled stoma. Drip live vaccine polio in the distal section of the intestine resulted in him antibodies only IgA class, and the title was significantly higher than in the proximal colon. Serum was found mainly IgG antibodies, a IgA antibodies appeared later, with the titer of them was significantly lower titers of IgG antibodies. Some authors suggest that sensitised lymphocytes stroma small intestine can penetrate into the blood and then get into the exocrine glands, including dairy, where they continue to produce antibodies (mainly IgA class) against the antigen to which they are sensitized [76-79A] (Fig. 3).

Fig. 3.
Circulation of lymphocytes from the intestine into the mammary gland (intermammary circulation). Special transport cages (M) carry entering the intestine mother antigen, bringing it to lymphoid cells (L)who are beginning to produce specific IgA antibodies. Then they migrate through the lymph vessels in the mesenteric nodes and thoracic lymphatic duct and then fall into the General circulation. In the period of hormonal stimulation of these cells accumulate in the breast and produce IgA antibodies against primary antigen, trapped in the body of the mother [Kleinman R. E., Walker W. A., 1979].