The CD4+ T cell response to a commensal-derived epitope transitions from a tolerant to an inflammatory state in Crohn's disease

Immunity. 2022 Oct 11;55(10):1909-1923.e6. doi: 10.1016/j.immuni.2022.08.016. Epub 2022 Sep 16.

Abstract

Reciprocal interactions between host T helper cells and gut microbiota enforce local immunological tolerance and modulate extra-intestinal immunity. However, our understanding of antigen-specific tolerance to the microbiome is limited. Here, we developed a systematic approach to predict HLA class-II-specific epitopes using the humanized bacteria-originated T cell antigen (hBOTA) algorithm. We identified a diverse set of microbiome epitopes spanning all major taxa that are compatible with presentation by multiple HLA-II alleles. In particular, we uncovered an immunodominant epitope from the TonB-dependent receptor SusC that was universally recognized and ubiquitous among Bacteroidales. In healthy human subjects, SusC-reactive T cell responses were characterized by IL-10-dominant cytokine profiles, whereas in patients with active Crohn's disease, responses were associated with elevated IL-17A. Our results highlight the potential of targeted antigen discovery within the microbiome to reveal principles of tolerance and functional transitions during inflammation.

Keywords: MHC class II; T cells; epitope prediction; immunodominance; inflammation; inflammatory bowel disease; metagenomics; microbial antigens; microbiome; mucosal immunology.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD4-Positive T-Lymphocytes
  • Crohn Disease*
  • Epitopes, T-Lymphocyte
  • Humans
  • Immunodominant Epitopes*
  • Interleukin-10
  • Interleukin-17

Substances

  • Epitopes, T-Lymphocyte
  • Immunodominant Epitopes
  • Interleukin-17
  • Interleukin-10