Surface expression of transglutaminase 2 by dendritic cells and its potential role for uptake and presentation of gluten peptides to T cells

Scand J Immunol. 2007 Mar;65(3):213-20. doi: 10.1111/j.1365-3083.2006.01881.x.

Abstract

Celiac disease is a chronic small intestinal inflammation driven by gluten-reactive T cells of the intestinal mucosa. These T cells are HLA-DQ2 or -DQ8 restricted, and predominantly recognize gluten peptides that are deamidated by the enzyme transglutaminase 2 (TG2). Our recent results strongly suggest that duodenal CD11c(+) dendritic cells (DC) are directly involved in T cell activation in the celiac lesion. The aim of this study was to investigate whether surface-associated TG2 could be involved in receptor-mediated endocytosis of gluten peptides, a process that may contribute to the preferential recognition of deamidated peptides. We found that both monocyte-derived DC and local CD11c(+) DC in the duodenal mucosa expressed cell surface-associated TG2. As phenotypic characterization of CD11c(+) DC in the celiac lesion suggests that these cells may be derived from circulating monocytes, we used monocyte-derived DC in functional in vitro studies. Using a functional T cell assay, we obtained evidence that cell surface-associated TG2 is endocytosed by monocyte-derived DC. However, we were unable to obtain evidence for a role of surface TG2 in the loading and subsequent generation of deamidated gluten peptides in these cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigen Presentation / immunology
  • Cell Membrane / metabolism
  • Dendritic Cells / immunology*
  • Dendritic Cells / metabolism
  • Endocytosis
  • Flow Cytometry
  • GTP-Binding Proteins / biosynthesis*
  • Glutens / immunology*
  • Glutens / metabolism
  • Humans
  • Immunity, Mucosal*
  • Intestinal Mucosa / immunology
  • Intestinal Mucosa / metabolism
  • Lymphocyte Activation / immunology
  • Protein Glutamine gamma Glutamyltransferase 2
  • T-Lymphocytes / immunology*
  • Transglutaminases / biosynthesis*

Substances

  • Glutens
  • Protein Glutamine gamma Glutamyltransferase 2
  • Transglutaminases
  • GTP-Binding Proteins