| Lactic acid bacteria exopolysaccharides (LAB EPS) is a sort of polysaccharides compound secrected to cell walls in the metabolic process. It had safe, non-toxic and unique physical a chemical nature, meanwhile had anti-tumor activity, immunomodulatory activity and regulation of gastrointestinal function and other aspects of the biological activity. Peyer’patches (PP) is considered to be the induction site of intestinal mucosal immunity, and play a pivotal role in the intestinal immunity and immune defense. PP contains a variety of immune cells, and it produced them itself or acquired from outside, such as APC and T, B lymphocytes, while the Th17cells is one of effect type T cells, which is differentiated form the CD4+T cells, mostly secreting cytokines of IL-17and IL-21,and are considered to be the key point of regulating all kinds of microbial infection, and play a dominant role in inflammatory bowel disease. Many studies indicate that the Lactobacillus casei exopolysaccharide, within many of the lactic acid bacteria polysaccharide, performs prominent immune regulation characteristics. This study is mainly expected to explore the influence of L.casei EPS on the differentiation of CD4+T cells to Th17and its path, and the effects of EPS on the essential condition of the Th17migration to PP, to clarify the regulation mechanism of Lactobacillus casei exopolysaccharide in those aspects.This study was mainly conducted in the following aspects:(1)Ferment cultures were made by centrifugation, trichloroacetic acid deproteinization, ethanol precipitation, dialysis and freeze drying steps crude to isolate polysaccharide.(2) Different concentration of L.casei EPS was given to six groups BALB/c mice for consecutive seven days, put these mice to death and separate Peyer’ patches.(3) With ELISA analysis method, expression of IL-17, IL-21and IL-22, that is, Th17standard cell factors were examinedto observe effect of L.casei EPS on CD4+T cells to Th17cell differentiation.(4) The expression of important cell factors in Th17cells differentiation process, TGF β-1, IL-6, IL-21, IL-23were analyzed by ELISA; key nuclear transcription factors ROR γt protein to Th17was analysized by western blot; Th17main inhibitory factor IL-4, IFN-γ andIL-2were analyzed by ELISA. To observe how L.casei EPS effect on CD4T cells, and what specific ways and means influence Th17cell differentiation. ELISA method respectively and relative quantitative PCR technology were used to show chemokine CCL20expression in different dose of EPS, CCL20is a necessary condition of Th17migration to PP.Results were showed as follows:(1) L.casei EPS could induce serection of IL-17, IL-21and IL-22in PP of mice,which were Th17type factors, and control its serection to avoid eccessive differentiation.(2) EPS could induce and control the expression of RORyt,it showed that EPS effect the Th17through RORyt.(3) EPS could stimulate secretion of cell factors that is good to Th17differentiation in PP, such as TGF β-IL-6, IL-23,It showed that EPS could induce the serection of those factors undirectly.(4) Under the effect of EPS, the relationship between Th17、Th1、Th2and Treg was to limite or promote each other.(5) EPSould promote the expression of chemokine CCL20and its mRNA, which played a key role in PP migration., but this promotion was conservatism.This showed EPS could adjust PP to secret different types of cell factors and the chemokine, as a result, a induction of the Th17type cell-mediated immune response wass induced.but it also controled the excessive response of Th17. It can be predicted that under inflammation conditions, EPS will make Th17migrate to PP.Conclusion:EPS were shown to induce CD4+T cells to Th17in PP, but it also controled the excessive response of Th17; EPS provide necessary condition that migration of Th17to PP. |
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