Humans and their microbiota have coevolved a mutually beneficial relationship in which the human host provides a hospitable environment for the microorganisms and the microbiota provides many advantages for the host, including nutritional benefits and protection from pathogen infection. Maintaining this relationship requires a careful immune balance to contain commensal microorganisms within the lumen while limiting inflammatory anti-commensal responses. Antigen-specific recognition of intestinal microorganisms by T cells has previously been described. Although the local environment shapes the differentiation of effector cells it is unclear how microbiota-specific T cells are educated in the thymus. Here we show that intestinal colonization in early life leads to the trafficking of microbial antigens from the intestine to the thymus by intestinal dendritic cells, which then induce the expansion of microbiota-specific T cells. Once in the periphery, microbiota-specific T cells have pathogenic potential or can protect against related pathogens. In this way, the developing microbiota shapes and expands the thymic and peripheral T cell repertoire, allowing for enhanced recognition of intestinal microorganisms and pathogens.
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http://dx.doi.org/10.1038/s41586-021-03531-1 | DOI Listing |
Trends Cell Biol
January 2025
Department of Immunology, Ophthalmology, and ENT, Universidad Complutense de Madrid, Instituto de Investigación Sanitaria Hospital 12 de Octubre (Imas12), Madrid, Spain. Electronic address:
The generation of regulatory T cells (Tregs) through interactions with antigen-presenting cells (APCs) is essential for establishing tolerance to gut commensals. Recent findings highlight the critical role of RORγt-lineage APCs, especially in gut-associated lymphoid tissues, in the induction of microbiota-specific peripheral Tregs and maintaining gut immune homeostasis.
View Article and Find Full Text PDFImmunity
October 2024
Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA; Perlmutter Cancer Center, New York University Langone Health, New York, NY 10016, USA; Howard Hughes Medical Institute, New York, NY 10016, USA. Electronic address:
bioRxiv
July 2024
Department of Cell Biology, New York University School of Medicine, New York, NY, USA.
The gastrointestinal tract is continuously exposed to foreign antigens in food and commensal microbes with potential to induce adaptive immune responses. Peripherally induced T regulatory (pTreg) cells are essential for mitigating inflammatory responses to these agents. While RORγt antigen-presenting cells (RORγt-APCs) were shown to program gut microbiota-specific pTregs, understanding of their characteristics remains incomplete, and the APC subset responsible for food tolerance has remained elusive.
View Article and Find Full Text PDFImmunity
July 2024
Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA, USA; Division of Medical Oncology, Department of Medicine, University of Washington, Seattle, WA, USA. Electronic address:
Allogeneic T cell expansion is the primary determinant of graft-versus-host disease (GVHD), and current dogma dictates that this is driven by histocompatibility antigen disparities between donor and recipient. This paradigm represents a closed genetic system within which donor T cells interact with peptide-major histocompatibility complexes (MHCs), though clonal interrogation remains challenging due to the sparseness of the T cell repertoire. We developed a Bayesian model using donor and recipient T cell receptor (TCR) frequencies in murine stem cell transplant systems to define limited common expansion of T cell clones across genetically identical donor-recipient pairs.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2023
Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO 63110.
Recent studies have characterized various mouse antigen-presenting cells (APCs) expressing the lymphoid-lineage transcription factor RORγt (Retinoid-related orphan receptor gamma t), which exhibit distinct phenotypic features and are implicated in the induction of peripheral regulatory T cells (Tregs) and immune tolerance to microbiota and self-antigens. These APCs encompass Janus cells and Thetis cell subsets, some of which express the AutoImmune REgulator (AIRE). RORγt MHCII type 3 innate lymphoid cells (ILC3) have also been implicated in the instruction of microbiota-specific Tregs.
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