Cutting edge: TLR2 directly triggers Th1 effector functions

J Immunol. 2007 Jun 1;178(11):6715-9. doi: 10.4049/jimmunol.178.11.6715.

Abstract

Toll-like receptors recognize pathogen-associated molecular patterns, activate innate immunity, and consequently modulate adaptive immunity in response to infections. TLRs are also expressed on T cells, and it has been shown that T cell activation is modulated by TLR ligands. However, the functions of TLRs on Th1 and Th2 effector cells and the molecular mechanisms underlying TLR-mediated activation are not fully understood. We analyzed TLR functions and downstream signaling events in both effector T cells. In mouse Th1 cells the stimulation by TLR2 but not by other TLRs directly induced IFN-gamma production, cell proliferation, and cell survival without TCR stimulation, and these effects were greatly enhanced by IL-2 or IL-12 through the enhanced activation of MAPKs. In contrast, no TLR affected the function of effector Th2 cells. These results identify TLR2 as a new specific activator of Th1 cell function and imply the involvement in Th1-mediated responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Proliferation
  • Cell Survival / immunology
  • Enzyme Activation / immunology
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Interferon-gamma / biosynthesis
  • Interleukin-12 / physiology
  • Interleukin-2 / physiology
  • Ligands
  • Lymphocyte Activation / immunology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Th1 Cells / cytology
  • Th1 Cells / immunology*
  • Th1 Cells / metabolism*
  • Th2 Cells / cytology
  • Th2 Cells / immunology
  • Th2 Cells / metabolism
  • Toll-Like Receptor 2 / deficiency
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / metabolism
  • Toll-Like Receptor 2 / physiology*
  • Up-Regulation / immunology

Substances

  • Interleukin-2
  • Ligands
  • Toll-Like Receptor 2
  • Interleukin-12
  • Interferon-gamma
  • Extracellular Signal-Regulated MAP Kinases