Regulation of intestinal immune networks by the DNA motifs from probiotics.

人们对酸奶对几种疾病的治疗和预防作用越来越感兴趣。德氏乳杆菌。保加利亚乳酸菌(L.Bulgaricus)和嗜热链球菌(S.thermophilus)是乳品乳酸菌(LAB)，在酸奶生产中得到了广泛的应用。在我们最近的研究中，我们特别关注酸奶发酵剂培养物中的DNA作为实验室免疫调节因子之一。本研究旨在阐明肠道中DNA的免疫调节功能。保加利亚乳杆菌和嗜热链球菌的DNA能显著刺激小鼠Peyer‘s斑块细胞的有丝分裂反应，并诱导细胞表面CD69。克隆了活性DNA，并在保加利亚乳杆菌NIAI B6中发现了类似CpG基序的DNA基序。保加利亚乳杆菌NIAI B6通过M细胞，被巨噬细胞/树突状细胞消化，通过DNA基序刺激免疫细胞。在Peyer‘s斑块细胞中证实了DNA基序的结合和摄取。DNA基序可增强派耶斑片中Th1型细胞因子(IL-7、IL-12、IL-18、干扰素γ)的表达。由于猪作为人类模型很有价值，根据其他哺乳动物IL-7的保守序列，用RACE方法从新生儿肠道上皮细胞中克隆了猪IL-7的cDNA.在B细胞、NK细胞、NKT细胞和树突状细胞等多种免疫细胞中检测到DNA基序诱导的细胞因子产生细胞。本研究证明保加利亚乳杆菌NIAI B6中存在粘膜免疫刺激DNA基序，并提出该微生物是生产新型功能食品“生物防御食品”的良好发酵剂。

A great interest has increased concerning the therapeutic and preventive effects of yogurt against several diseases. Lactobacillus delbrueckii ssp. bulgaricus (L.bulgaricus) and Streptococcus thermophilus (S.thermophilus), which are dairy lactic acid bacteria (LAB), has been commonly used in yogurt production in the world. In our recent study, we have been particularly focusing on the DNA from yogurt starter cultures as one of the immunomoduratory factors in the LAB.The present study was conducted to elucidate the immunomoduratory functions of the DNA in the gut. The DNA from L.bulgaricus and S.thermophilus significantly stimulated mitogenic responses to murine peyer's patch cells and induced CD69 on the cells. The active DNA was cloned and the DNA motif, looks like CpG motif, was found in L.bulgaricus NIAI B6. L.bulgaricus NIAI B6 was passed through the M cells and digested by macrophage/dendritic cells result in the stimulation of immune cells by the DNA motif. The binding and ingestion of the DNA motif were demonstrated in peyer's patch cells. The DNA motif augmented induction of Th1 type cytokine (IL-7, IL-12, IL-18, IFNγ) mRNA in peyer's patches. Since swine will be valuable as a human model, swine IL-7 cDNA was isolated from neonatal intestinal epithelium by the RACE methods with designated primers based on the conserved sequences of the other mammalian IL-7. Cytokine producing cells induced by the DNA motif were detected in several immune cells such as B, NK, NKT and Dendritic cells. This study demonstrated that mucosal immunostimulatory DNA motif exist in L.bulgaricus NIAI B6 and proposed that the microorganism is a good candidate of a starter culture for the production of new functional foods, "Bio-Defense Foods".