Differential controls of MAIT cell effector polarization by mTORC1/mTORC2 via integrating cytokine and costimulatory signals

Nat Commun. 2021 Apr 1;12(1):2029. doi: 10.1038/s41467-021-22162-8.

Abstract

Mucosal-associated invariant T (MAIT) cells have important functions in immune responses against pathogens and in diseases, but mechanisms controlling MAIT cell development and effector lineage differentiation remain unclear. Here, we report that IL-2/IL-15 receptor β chain and inducible costimulatory (ICOS) not only serve as lineage-specific markers for IFN-γ-producing MAIT1 and IL-17A-producing MAIT17 cells, but are also important for their differentiation, respectively. Both IL-2 and IL-15 induce mTOR activation, T-bet upregulation, and subsequent MAIT cell, especially MAIT1 cell, expansion. By contrast, IL-1β induces more MAIT17 than MAIT1 cells, while IL-23 alone promotes MAIT17 cell proliferation and survival, but synergizes with IL-1β to induce strong MAIT17 cell expansion in an mTOR-dependent manner. Moreover, mTOR is dispensable for early MAIT cell development, yet pivotal for MAIT cell effector differentiation. Our results thus show that mTORC2 integrates signals from ICOS and IL-1βR/IL-23R to exert a crucial role for MAIT17 differentiation, while the IL-2/IL-15R-mTORC1-T-bet axis ensures MAIT1 differentiation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Differentiation / immunology
  • Cells, Cultured
  • Cytokines / immunology*
  • Cytokines / metabolism
  • Humans
  • Inducible T-Cell Co-Stimulator Protein / immunology*
  • Inducible T-Cell Co-Stimulator Protein / metabolism
  • Interleukin-15 / immunology
  • Interleukin-15 / metabolism
  • Interleukin-2 / immunology
  • Interleukin-2 / metabolism
  • Lymphocyte Activation / immunology*
  • Mechanistic Target of Rapamycin Complex 1 / immunology*
  • Mechanistic Target of Rapamycin Complex 1 / metabolism
  • Mechanistic Target of Rapamycin Complex 2 / immunology*
  • Mechanistic Target of Rapamycin Complex 2 / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Mucosal-Associated Invariant T Cells / cytology
  • Mucosal-Associated Invariant T Cells / immunology*
  • Mucosal-Associated Invariant T Cells / metabolism
  • Signal Transduction / immunology
  • TOR Serine-Threonine Kinases / immunology
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • Cytokines
  • Inducible T-Cell Co-Stimulator Protein
  • Interleukin-15
  • Interleukin-2
  • Mechanistic Target of Rapamycin Complex 1
  • Mechanistic Target of Rapamycin Complex 2
  • TOR Serine-Threonine Kinases