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Updated: May 10, 2026

Induction of Intestinal Inflammation by Adoptive Transfer of CBir1 TCR Transgenic CD4+ T Cells to Immunodeficient Mice
Published on: December 16, 2021
Double-stranded RNA of intestinal commensal but not pathogenic bacteria triggers production of protective
Tadaomi Kawashima1, Akemi Kosaka, Huimin Yan
1Biomedical Research Institute, National Institute for Advanced Industrial Science and Technology-AIST, Tsukuba, Ibaraki 305-8566, Japan.
Abstract:
The small intestine harbors a substantial number of commensal bacteria and is sporadically invaded by pathogens, but the response to these microorganisms is fundamentally different. We identified a discriminatory sensor by using Toll-like receptor 3 (TLR3). Double-stranded RNA (dsRNA) of one major commensal species, lactic acid bacteria (LAB), triggered interferon-β (IFN-β) production, which protected mice from experimental colitis. The LAB-induced IFN-β response was diminished by dsRNA digestion and treatment with endosomal inhibitors. Pathogenic bacteria contained less dsRNA and induced much less IFN-β than LAB, and dsRNA was not involved in pathogen-induced IFN-β induction. These results identify TLR3 as a sensor to small intestinal commensal bacteria and suggest that dsRNA in commensal bacteria contributes to anti-inflammatory and protective immune responses.
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