Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida Gainesville, FL, USA ; Division of Gastroenterology Hepatology & Nutrition, Department of Medicine, College of Medicine, University of Florida Gainesville, FL, USA.
Front Immunol. 2013 Feb 6;4:25. doi: 10.3389/fimmu.2013.00025. eCollection 2013.
As highlighted by the development of intestinal autoinflammatory disorders when tolerance is lost, homeostatic interactions between gut microbiota, resident immune cells, and the gut epithelium are key in the maintenance of gastrointestinal health. Gut immune responses, whether stimulatory or regulatory, are dictated by the activated dendritic cells (DCs) that first interact with microorganisms and their gene products to then elicit T and B cell responses. Previously, we have demonstrated that treatment with genetically modified Lactobacillus acidophilus is sufficient to tilt the immune balance from proinflammatory to regulatory in experimental models of colitis and colon cancer. Given the significant role of DCs in efficiently orchestrating intestinal immune responses, characterization of the signals induced within these cells by the surface layer molecules, such as lipoteichoic acid (LTA), and proteins of L. acidophilus is critical for future treatment and prevention of gastrointestinal diseases. Here, we discuss the potential regulatory pathways involved in the downregulation of pathogenic inflammation in the gut, and explore questions regarding the immune responses to LTA-deficient L. acidophilus that require future studies.
正如肠道自身炎症性疾病的发展所强调的那样,当耐受丧失时,肠道微生物群、固有免疫细胞和肠道上皮之间的稳态相互作用是维持胃肠道健康的关键。肠道免疫反应无论是刺激还是调节,都取决于最初与微生物及其基因产物相互作用的活化树突状细胞 (DC),然后引发 T 和 B 细胞反应。以前,我们已经证明,用基因修饰的嗜酸乳杆菌治疗足以使实验性结肠炎和结肠癌模型中的免疫平衡从促炎转向调节。鉴于 DC 在有效协调肠道免疫反应中的重要作用,因此,表征这些细胞内由表面层分子(如脂磷壁酸 (LTA))和嗜酸乳杆菌蛋白诱导的信号对于未来治疗和预防胃肠道疾病至关重要。在这里,我们讨论了参与肠道中致病性炎症下调的潜在调节途径,并探讨了有关对缺乏 LTA 的嗜酸乳杆菌的免疫反应的问题,这些问题需要进一步研究。