Dedicated immunosensing of the mouse intestinal epithelium facilitated by a pair of genetically coupled lectin-like receptors

Mucosal Immunol. 2015 Mar;8(2):232-42. doi: 10.1038/mi.2014.60. Epub 2014 Jul 2.

Abstract

The integrity of the intestinal epithelium is constantly surveyed by a peculiar subset of innate-like T lymphocytes embedded in the epithelial cell layer, hence called intestinal intraepithelial lymphocytes (IELs). IELs are thought to act as "first-line" sentinels sensing the state of adjacent epithelial cells via both T-cell receptors and auxiliary receptors. Auxiliary receptors modulating IEL activity include C-type lectin-like receptors encoded in the natural killer gene complex such as NKG2D. Here, we report that the CTLR Nkrp1g is expressed by a subpopulation of mouse CD103(+) IELs allowing immunosensing of the intestinal epithelium through ligation of the genetically coupled CTLR Clr-f that is almost exclusively expressed on differentiated intestinal epithelial cells (IECs). Most of these Nkrp1g-expressing IELs exhibit a γδTCR(bright)Nkg2a(-) phenotype and are intimately associated with the intestinal epithelium. As Clr-f expression strongly inhibits effector functions of Nkrp1g-expressing cells and is upregulated upon poly(I:C) challenge, Clr-f molecules may quench reactivity of these IELs towards the epithelial barrier that is constantly provoked by microbial and antigenic stimuli. Altogether, we here newly characterize a genetically linked C-type lectin-like receptor/ligand pair with a highly restricted tissue expression that apparently evolved to allow for a dedicated immunosurveillance of the mouse intestinal epithelium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Female
  • Gene Expression
  • Humans
  • Immunophenotyping
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / immunology*
  • Intestinal Mucosa / metabolism*
  • Lectins, C-Type / chemistry
  • Lectins, C-Type / genetics*
  • Lectins, C-Type / metabolism
  • Lymphocytes / immunology
  • Lymphocytes / metabolism
  • Mice
  • Multigene Family
  • NK Cell Lectin-Like Receptor Subfamily B / genetics
  • NK Cell Lectin-Like Receptor Subfamily B / metabolism
  • Organ Specificity / genetics
  • Peyer's Patches / cytology
  • Peyer's Patches / immunology
  • Peyer's Patches / metabolism
  • Phenotype
  • Poly I-C / pharmacology
  • Protein Binding
  • Protein Multimerization
  • Receptors, Antigen, T-Cell / metabolism
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocyte Subsets / metabolism

Substances

  • Lectins, C-Type
  • NK Cell Lectin-Like Receptor Subfamily B
  • Receptors, Antigen, T-Cell
  • Poly I-C