Environmental cues shape the development of immune tissues and also regulate immune responses. Kiss et al. now show that natural ligands of the aryl hydrocarbon receptor (AhR) are important for the postnatal development of specialized immune structures in the gut called intestinal lymphoid follicles and for protective responses against the enteric bacterium Citrobacter rodentium. AhR ligands in the diet regulated the size of the innate lymphocyte pools, and mice fed diets that lacked AhR ligands exhibited impaired intestinal lymphoid follicle development.
E. A. Kiss, C. Vonarbourg, S. Kopfmann, E. Hobeika, D. Finke, C. Esser, A. Diefenbach, Natural aryl hydrocarbon receptor ligands control organogenesis of intestinal lymphoid follicles. Science 334, 1561–1565 (2011). [Abstract] [Full Text]