Inflammatory bowel disease (IBD) has been attributed to overexuberant host immunity or the emergence of harmful intestinal flora. The transcription factor T-bet orchestrates inflammatory genetic programs in both adaptive and innate immunity. We describe a profound and unexpected function for T-bet in influencing the behavior of host inflammatory activity and commensal bacteria. T-bet deficiency in the innate immune system results in spontaneous and communicable ulcerative colitis in the absence of adaptive immunity and increased susceptibility to colitis in immunologically intact hosts. T-bet controls the response of the mucosal immune system to commensal bacteria by regulating TNF-α production in colonic dendritic cells, critical for colonic epithelial barrier maintenance. Loss of T-bet influences bacterial populations to become colitogenic, and this colitis is communicable to genetically intact hosts. These findings reveal a novel function for T-bet as a peacekeeper of host-commensal relationships and provide new perspectives on the pathophysiology of IBD. © 2007 Elsevier Inc. All rights reserved.
Garrett, W. S., Lord, G. M., Punit, S., Lugo-Villarino, G., Mazmanian, S. K. K., Ito, S., … Glimcher, L. H. (2007). Communicable Ulcerative Colitis Induced by T-bet Deficiency in the Innate Immune System. Cell, 131(1), 33–45. https://doi.org/10.1016/j.cell.2007.08.017