Immune system intestinal microbiota

Magrone T, Jirillo E. The interplay between the gut immune system and microbiota in health and disease nutraceutical intervention for restoring intestinal homeostasis. Curr Pharm Des. 2013 19 1329-1342. 

V. Effect of Intestinal Microbiota on the Immune System Preclinical Studies... 

There is accumulating evidence that the interaction between the intestinal microbiota and the gut plays an important role for the postnatal development of the immune system. However, the interactions between the intestinal epithehal and immune cells and the different species of the intestinal microbiota are very complex and not fully understood. The complexity of these interactions is based on the fact that on the one hand the human defense system consists of several layers, for example, of mechanical and chemical barriers (first line of defence) as well as innate and adaptive immunity (67) all of which can be influenced by microbiota (68). 

In the same experiments, different classical fiber mixtures in a similar dose to the GOS/lcFOS mixture were tested. There was no effect of these fibers on the measured parameter of the immune system, indicating that different nondigestible carbohydrates react differently with respect to intestinal microbiota and immune function (71). 

In summary, the animal data allow the conclusion that prebiotics, like the mixture of GOS/lcFOS, modulate the immune system and provide a preventive effect with regard to the development of allergic diseases. This effect is mainly mediated by modulation of the intestinal microbiota. 

There is increasing evidence that the interaction between the intestinal microbiota and the intestinal epithelial and immune cells plays a key role in the postnatal development of the immune system. First studies with probiotics (74) and synbio-tics (40) demonstrate effects during infancy, and studies regarding the vaccination response in the elderly (75) indicate that the prebiotics might also influence the immune system. In particular, the animal experiments with prebiotics described above allow the hypothesis that prebiotics that are able to influence the composition of the entire intestinal microbiota toward microbiota found in breastfed infants might support the development of the immune system during infancy. 

Proper development of immune tolerance is necessary for the maintenance of gut homeostasis and an efficient response against pathogens. Dysregulation of the involved mechanisms can lead to inappropriate intestinal inflammation against microbiota, such as inflammatory bowel disease. The immaturity of the neonatal immune system explains the age-dependent differences of the immune responses against pathogens and the susceptibility to different types of infection (Tourneur and Chassin 2013). 

Purchiaroni, F., Tortora, A., Gabrielli, M., Bertucci, R, Gigante, G., laniro, G., et al. (2013). The role of intestinal microbiota and the immune system. European Review for Medical and Pharmacological Sciences, 17(3), 323-333. 

Hooper LV, Littman DR, Macpherson AJ. Interactions between the microbiota and the immune system. Science. 2012 336 1268-1273. Wardwell LH, Huttenhower C, Garrett WS. Current concepts of the intestinal microbiota and the pathogenesis of infection. Curr Infect Dis Rep. 2011 13 28-34. 

However, the probiotic concept should be interpreted very carefully, particularly when one considers how the numerous different members of the gut microbiota and the highly complex interactions that occur within this vast microbial consortium may affect the metabolism and the immune-system of the host. The intestinal microbiota and its host enjoy a "fluctuating" relationship that depends on the type of bacterial species present. Symbiotic components may be present where both partners derive benefit from this relationship, but this may turn into commensalism where only a single partner enjoys a positive effect from the interaction. ... 

Macpherson AJ, Harris NL (2004) Interactions between commensal intestinal bacteria and the immune system. Nat Rev Immunol 4(6) 478 85 Maslowski KM, Mackay CR (2011) Diet, gut microbiota and immune responses. Nat Immunol 12(l) 5-9. doi 10.1038/Ni0111-5... 

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