The Microbiota Limit CX3CR1+ Cell-Dependent Trafficking of a Pathogenic Bacterium to the Mesenteric Lymph Nodes. (71.9)
| Autor: | Gretchen Diehl, Randy Longman, Jing-Xin Zhang, Beatrice Breart, Susan Schwab, Dan Littman |
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| Rok vydání: | 2012 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 188:71.9-71.9 |
| ISSN: | 1550-6606 0022-1767 |
| Popis: | The organization of the intestine makes regulating inflammation a unique challenge. The lumen of the intestine contains not only partially digested food, but also an enormous load of beneficial bacteria (up to 10^12 organisms/gram of contents). As commensal and pathogenic bacteria contain the same immunostimulatory molecules, it is unclear how the intestinal immune system can distinguish between the two. We hypothesized that recognition of commensals modulates intestinal immune responses to limit inflammation. To this end, we examined immune responses against non-invasive Salmonella Typhimurium in MyD88-deficient mice or wildtype mice treated with antibiotics to reduce their microbiota. We found that, in the presence of commensals, non-invasive Salmonella, a pathogen whose entry is limited, is unable to reach the mesenteric lymph nodes (MLN). However, in animals where the load of commensals has been reduced with antibiotics or in animals deficient for MyD88, non-invasive Salmonella trafficks to the MLN in a CCR7-dependent manner. This trafficking to the MLN results in the induction of IgA. Additionally, we found that CX3CR1+ mononuclear phagocytes, an intestinal cell population previously thought to be non-migratory, are responsible for this trafficking of non-invasive Salmonella. These findings indicate that recognition of commensals limits the amount of antigen reaching the MLN. This in turn limits induction of immune responses and serves to reduce intestinal inflammation. |
| Databáze: | OpenAIRE |
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