Hepatocytes and IL-15: a favorable microenvironment for T cell survival and CD8+ T cell differentiation

J Immunol. 2009 May 15;182(10):6149-59. doi: 10.4049/jimmunol.0802470.

Abstract

Human intrahepatic lymphocytes are enriched in CD1d-unrestricted T cells coexpressing NKR. Although the origin of this population remains controversial, it is possible to speculate that the hepatic microenvironment, namely epithelial cells or the cytokine milieu, may play a role in its shaping. IL-15 is constitutively expressed in the liver and has a key role in activation and survival of innate and tissue-associated immune cells. In this in vitro study, we examined whether hepatocyte cell lines and/or IL-15 could play a role in the generation of NK-like T cells. The results show that both HepG2 cells and a human immortalized hepatocyte cell line increase survival and drive basal proliferation of T cells. In addition, IL-15 was capable of inducing Ag-independent up-regulation of NKR, including NKG2A, Ig-like receptors, and de novo expression of CD56 and NKp46 in CD8(+)CD56(-) T cells. In conclusion, our study suggests that hepatocytes and IL-15 create a favorable microenvironment for T cells to growth and survive. It can be proposed that the increased percentage of intrahepatic nonclassical NKT cells could be in part due to a local CD8(+) T cell differentiation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD8-Positive T-Lymphocytes / cytology
  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / metabolism
  • Cell Communication / immunology
  • Cell Differentiation / immunology*
  • Cell Line
  • Cell Survival / immunology*
  • Coculture Techniques
  • Flow Cytometry
  • Hepatocytes / immunology*
  • Hepatocytes / metabolism
  • Humans
  • Interleukin-15 / immunology*
  • Interleukin-15 / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • T-Lymphocyte Subsets / cytology
  • T-Lymphocyte Subsets / immunology*
  • T-Lymphocyte Subsets / metabolism

Substances

  • Interleukin-15