The role of commensal microflora in the inane immune response during infection

本研究探讨了消化道细菌在实验性脓毒症小鼠天然免疫应答中的作用。实验小鼠用含有多种抗生素（链霉素和头孢噻肟）的水喂养三周。实验组肠道细菌植物群数量显著减少，肠道有机酸谱发生变化。流式细胞术检测腹腔巨噬细胞TLR-4和TLR-2受体表达明显下调。脂多糖注射后血浆TNF-α水平升高（模拟临床脓毒症）已减弱。这种衰减伴随着死亡率的增加。这些数据表明，肠道细菌植物群可能在调节先天免疫系统中发挥重要作用。在脓毒症的治疗中，应考虑抗菌药物通过肠道菌群的变化而发挥的免疫调节作用。

We investigated the role of digestive commensal bacteria in the innate immune response in experimental mouse sepsis model. Experimental mice were fed by water including multiple antibiotics (streptomycin and cefotaxime) for three weeks. Significant decreases in the amount of commensal bacterial flora, as well as the changes in intestinal organic acid profiles were noted in the experimental group. The expressions of TLR-4 and TLR-2 receptors in the peritoneal macrophages assessed by flow-cytometry, have been significantly downregulated. The increase in plasma TNF-α level after lipopolysaccharide injection, mimicking clinical sepsis, has been attenuated. This attenuation was accompanied with the increases in the mortality. Those data suggests that commensal bacterial flora in the digestive tract might confer a significant role in modulating innate immune system. The immunomodulating effect of antimicrobials via the changes in commensal microflora should be considered in the sepsis treatment.