IL-2 signaling prevents T cell anergy by inhibiting the expression of anergy-inducing genes

Mol Immunol. 2009 Feb;46(5):999-1006. doi: 10.1016/j.molimm.2008.09.029. Epub 2008 Nov 5.

Abstract

T cell responses are determined by the environment in which antigen is encountered. In the absence of proper costimulation, anergizing stimuli induce the activation of a specific program of gene expression. Proteins encoded by these genes impose a state of functional unresponsiveness in anergic T cells through the activation of different mechanisms that include dampening of the T cell receptor signaling and direct inhibition of cytokine expression. Anergy can be reversed by stimulating T cells in the presence of interleukin (IL-)2. Signaling through the IL-2 receptor has been shown to activate mTOR, which plays an important role in the integration of signals that determine the fate of T cells. The mechanisms underlying the IL-2-dependent regulation of T cell tolerance are still not fully elucidated. In this study we show that IL-2 receptor signaling mediated through JAK3 and mTOR inhibits the expression of anergy-inducing genes independently of any effect on cell cycle progression. Interestingly, we also show that this effect is likely due to changes on the levels of AP-1 activation induced by IL-2 receptor signaling in T cells. Our data identifies a mechanism that can explain how IL-2 may prevent or reverse the establishment of anergy in T cells and, therefore, helps to understand how the cytokine environment can be determinant to shape the outcome of T cell responses - tolerance or activation - when antigen is encountered.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Cycle / immunology*
  • Clonal Anergy
  • Gene Expression Regulation / immunology*
  • Interleukin-2 / immunology*
  • Janus Kinase 3 / immunology
  • Mice
  • Mice, Inbred BALB C
  • Protein Kinases / immunology
  • Receptors, Interleukin-2 / immunology
  • Signal Transduction / immunology*
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • TOR Serine-Threonine Kinases
  • Transcription Factor AP-1 / immunology

Substances

  • Interleukin-2
  • Receptors, Interleukin-2
  • Transcription Factor AP-1
  • Protein Kinases
  • mTOR protein, mouse
  • Jak3 protein, mouse
  • Janus Kinase 3
  • TOR Serine-Threonine Kinases