Has the Microbiota Played a Critical Role in the Evolution of the Adaptive Immune System?

A Gutsy Analysis Efforts to sequence the human microbiome—the genomes of all the microbes that inhabit our bodies—have demonstrated its enormous diversity. Analyses to probe the various functions of the microbiota, particularly of those that reside in the gut, have revealed that our microbiota has a profound impact on the development and function of our immune systems. Lee and Mazmanian (p. 1768 ) review how the microbiota influences the development of the adaptive immune system. Specific species and families of microbiota support the differentiation of particular populations of T cells, and alterations in intestinal microbiota affect the development of inflammation and autoimmunity.