The interaction between host and microbiota previously defined in a reductive as diner (only one of the two benefits), is actually very active, symbiotic or mutualistic, where the immunity system is the most involved in this report, especially in maintaining the balance between tolerance and immune activation.
The immunological surveillance of the populations of intestinal microorganisms involves receptor proteins belong to the class of pattern recognition receptors (PPR), which recognize the structural reasons preserved expressed by microorganisms, pathogen associated molecular patterns (PAMP) through the toll- like receptors (toll-like receptors, TLRs) and nucleotide binding oligomerization domain (NOD). These receptors act in distinct cellular compartments thus contributing to tolerance towards commensal bacteria and food-borne antigens . The recognition of these receptors on the apical surface of the epithelium promotes tolerance and the right tone inflammatory; on the contrary the activation of these same receptors from the side basolateral promotes strong inflammatory responses.
Cooperative as well as competitive interactions may occur between the microbiota, via 'pattern recognition receptors' (TLRs and NODs), or other components of the innate immune system leading to pro-inflammatory or anti-inflammatory immune responses in different cell types.
The intestinal microflora plays a definitely important role both in intestinal inflammation that in the development of tumors of the gastro-intestinal tract. Alterations of this ecosystem have been observed such as in older people with cancer of the colon and rectum. In particular, it has been highlighted the prevalence of clostridia at the expense of bifidobacteria compared to healthy elderly in these individuals . The interaction between the microbiota and the immune system in cancer patients is important not only for the aspects of the pathogenesis but also because it can provide an opportunity for therapeutic management/ frequency of surgical complications is related to the assumption of chemotherapy (lower incidence of secondary complications).
Using Soluble Fractions of Dietary Fiber as Immunological Adjuvants
The '-glucans are linear polysaccharides consisting of glucose molecules joined together by glycosidic bonds . Some types of beta-glucan are destroyed by the gastric juices and thus are not orally active, but the beta fraction 1,3-1,6-D-glucan, derived from baker's yeast, is stable. The receptors Members of the recognition of the beta-l, 3-1.6 D-glucan are expressed by macrophages and thus able to induce the activation. In a study conducted by Bogwald & collaborators , it was shown that activated macrophages from glucan are able to recognize and phagocytose different types of cancer cells such as melanoma and mast cell tumor, while other researchers have shown that the glucan is capable of significantly reduce the growth of breast cancer cells and B16 melanoma in mouse models, suggesting that the glucan possesses also antitumor activity [10,11].
The beneficial properties of beta-glucans in the supportive care of cancer are now well defined and clearly associated with their immunomodulatory activity . It 'also known, that the combination of beta-glucans with other natural compounds can potentiate the activity. In particular, the acid ascorbic acid (vitamin C) is an important factor in the processes of macrophage activation. In fact, the activated macrophage consuming and requires ascorbic acid in amounts to 1,000 times higher than those present in the blood. More recent studies have shown that some bioactive molecules, such as vitamin C and resveratrol can further boost the impact of beta-glucan, when given in combination [12,13]. It was observed that their combination suppresses more effectively the growth of mammary tumors and lung, promoting apoptosis of the cancerous cells. In this regard, some polysaccharides such as the '-Glucan, can be used not only for their ability to act as immunostimulants but also as prebiotics. Indeed, the '-glucans are highly fermented by the gut microbiota blind and the small intestine and can increase the rate of growth and production of lactic acid of microbes isolated human intestine . These findings could open up new therapeutic prospects integration using appropriate strains of probiotics combined with micronutrients ('-Glucan, Vit. C, resveratrol) in maintaining a healthy intestinal environment (eubiosis) and for a proper balance of the innate immune system.