Centro de Referencia para Lactobacilos (CERELA-CONICET), Chacabuco 145, San Miguel de Tucumán (T4000ILC), Argentina.
Int J Food Microbiol. 2010 Apr 15;138(3):223-31. doi: 10.1016/j.ijfoodmicro.2010.01.020. Epub 2010 Feb 1.
The prevention of pathogen infections is one of the most extensively studied effects of probiotics. L. casei CRL 431 is a probiotic bacterium and its effects on the gut immune cells have been extensively studied. The aim of the present study was to determine, using a mouse model, the preventive and therapeutic effect of L. casei CRL 431 to achieve protection against Salmonella enteritidis serovar Typhimurium infection. In both previous and continuous (previous and post-infection) probiotic administration, the mechanisms induced by this lactic acid bacteria on the first line of intestinal defense (non-specific barrier and the innate immune cells associated to the gut), as a way to understand some of the mechanisms involved in the protection against Salmonella enteritidis serovar Typhimurium, were analyzed. The results obtained demonstrated that 7 days L. casei CRL 431 administration before infection decreased the severity of the infection with Salmonella enteritidis serovar Typhimurium, demonstrating that the continuous administration (even after infection) had the best effect. This continuous administration diminished the counts of the pathogen in the intestine as well as its spread outside this organ. Several mechanisms and cells are involved in this protective effect against Salmonella enteritidis serovar Typhimurium. L. casei CRL 431 acted on cells of the innate and adaptive immune response. The probiotic administration decreased the neutrophil infiltration with the consequent diminution of intestinal inflammation; activated the macrophage phagocytic activity in different sites such as Peyer's patches, spleen and peritoneum; and increased the number of IgA+cells in the lamina propria of the small intestine which was correlated with increased release of s-IgA specific against the pathogen in the intestinal fluids. The mechanism of the inhibition of cellular apoptosis was not involved.
益生菌的最广泛研究的作用之一是预防病原体感染。干酪乳杆菌 CRL431 是一种益生菌，其对肠道免疫细胞的影响已被广泛研究。本研究的目的是使用小鼠模型确定干酪乳杆菌 CRL431 的预防和治疗效果，以实现对肠炎沙门氏菌 Typhimurium 感染的保护。在以前和连续（以前和感染后）益生菌给药中，这种乳酸菌对肠道第一道防线（非特异性屏障和与肠道相关的固有免疫细胞）的诱导机制，以了解一些参与保护肠炎沙门氏菌 Typhimurium 的机制，进行了分析。结果表明，感染前 7 天给予干酪乳杆菌 CRL431 可降低肠炎沙门氏菌 Typhimurium 感染的严重程度，表明连续给药（甚至在感染后）效果最佳。这种连续给药减少了肠道内病原体的数量及其在器官外的传播。几种机制和细胞参与了这种对肠炎沙门氏菌 Typhimurium 的保护作用。干酪乳杆菌 CRL431 作用于先天和适应性免疫反应的细胞。益生菌给药减少了中性粒细胞的浸润，从而减少了肠道炎症；激活了吞噬活性在不同部位如派尔集合淋巴结、脾脏和腹膜的巨噬细胞；并增加了小肠固有层中 IgA+细胞的数量，这与肠道分泌物中针对病原体的 s-IgA 特异性释放增加有关。细胞凋亡抑制机制不参与其中。
