ABSTRACT
The characterization of the human microbiome by molecular typing has paved the way to new insights on the interaction of the microbiota and our immune system and revealed numerous associations of immunological diseases with microbiota disruption. In the last years, more and more mechanisms explaining these interactions have been described. Among them, membrane and cytosolic receptors of pathogen-associated molecules induce various pathways of inflammation, and bacterial metabolites like short chain fatty acids, secondary bile acids, or indoles modulate homeostasis of epithelial as well as a variety of cells of innate and adaptive immunity. Three major clinical situations discussed in this chapter are the role of microbiota in transplantation, their contribution to autoimmune diseases, and the increasing role of microbiota in tumor immunotherapy.
