Intestinal immunology

The microbiota - the collection of microorganisms that live within and on all mammals - provides crucial signals for the development and function of the immune system. Increased availability of technologies that profile microbial communities is facilitating the entry of many immunologists into the evolving field of host-microbiota studies. The microbial communities, their metabolites and components are not only necessary for immune homeostasis, they also influence the susceptibility of the host to many immune-mediated diseases and disorders...

In most chronic inflammatory diseases, the cause remains unknown. Chronic infection is, however, among the current hypotheses. Recent technological advances have allowed in-depth studies of the gut microflora, or microbiota, which contains a vast array of organisms, most of which cannot be cultured. Inflammatory bowel disease has been associated with distinctive changes in the gut microbiota, which persist between disease flares and may play a pathogenic role. Links have been demonstrated between the gut microbiota and joint inflammation in murine models of arthritis but have received little attention in human patients...

Changes in bacterial communities are associated with the pathogenesis of many diseases including inflammatory bowel disease and liver disease. Dysbiosis can induce intestinal inflammation resulting in increased intestinal permeability and bacterial translocation. The majority of chronic liver diseases are associated with bacterial translocation resulting in or enhancing an inflammatory response in the liver. Intestinal inflammation and a dysfunctional intestinal barrier are not sufficient to cause liver disease in the absence of an additional liver insult...

Proper adaptation to environmental perturbations is essential for tissue homeostasis. In the intestine, diverse environmental cues can be sensed by immune cells, which must balance resistance to microorganisms with tolerance, avoiding excess tissue damage. By applying imaging and transcriptional profiling tools, we interrogated how distinct microenvironments in the gut regulate resident macrophages. We discovered that macrophages exhibit a high degree of gene-expression specialization dependent on their proximity to the gut lumen...