AUTHOR=Arrieta Marie-Claire, Finlay Barton TITLE=The Commensal Microbiota Drives Immune Homeostasis JOURNAL=Frontiers in Immunology VOLUME=3 YEAR=2012 URL=https://www.frontiersin.org/articles/10.3389/fimmu.2012.00033 DOI=10.3389/fimmu.2012.00033 ISSN=1664-3224 ABSTRACT=For millions of years, microbes have coexisted with eukaryotic cells at the mucosal surfaces of vertebrates in a complex, yet usually harmonious symbiosis. An ever-expanding number of reports describe how eliminating or shifting the intestinal microbiota has profound effects on the development and functionality of the mucosal and systemic immune systems. Here, we examine some of the mechanisms by which bacterial signals affect immune homeostasis. Focusing on the strategies that microbes use to keep our immune system healthy, as opposed to trying to correct the immune imbalances caused by dysbiosis, may prove to be a more astute and efficient way of treating immune-mediated disease.