Understanding the impact of food components and microbial metabolites on interactions of gut microbes with the immune system

目前关于肠道微生物与免疫系统相互作用的重要作用的证据引起了人们对益生菌、益生元和膳食纤维的强烈兴趣。然而，应用益生菌的最新知识和通过饮食策略来控制肠道微生物的尝试结果好坏参半。基于饮食-微生物策略的结果不仅取决于微生物、食物成分和由此产生的微生物代谢物，而且还受宿主因素的影响。例如，女性和男性在益生元对免疫系统的影响方面的差异表明，基于性别的因素可以产生饮食和肠道微生物治疗结果的差异。然而，在益生元和益生菌的研究中很少涉及这方面。关于使用益生菌的其他问题包括食用益生菌的食物对其活性的影响。肠上皮细胞（IEC）和抗原提呈细胞（APC）在肠道界面的免疫活动中是不可或缺的，它们在那里遇到肠道微生物、食物成分和微生物代谢物。微生物代谢物和可溶性介质越来越被认为是益生菌、饮食和肠道微生物对免疫系统影响的关键参与者。关于益生菌、食物成分、微生物代谢物和宿主影响的相互作用网络的知识空白必须填补，以便设计有效的使用策略。

Current evidence for essential roles of gut microbe interactions with the immune system has generated strong interest in probiotics, prebiotics and dietary fibres. However, attempts to apply recent knowledge about probiotics and to manipulate gut microbes through strategic use of diet have had mixed results. Outcomes of diet-microbe based strategies not only depend on microbes, food components and the resulting microbial metabolites, but are also influenced by host factors. For example, differences between females and males in impact of prebiotics on the immune system show that sex-based factors can generate variation in outcomes of diet and gut microbe-based treatments. However, this aspect is rarely addressed in studies of prebiotics and probiotics. Other questions about use of probiotics include the impact that the foods they are consumed in have their activity. Intestinal epithelial cells (IEC) and antigen presenting cells (APC) are integral in immune activity at the intestinal interface, where they encounter gut microbes, food components and microbial metabolites. Microbial metabolites and soluble mediators are increasingly seen as key participants in effects of probiotics, diet and gut microbes on the immune system. Gaps in knowledge about the network of interactions involving probiotics, food components, microbial metabolites and host impact must be filled in order to design effective strategies for their use.