CCR8 + FOXp3 + T reg cells as master drivers of immune regulation

Proc Natl Acad Sci U S A. 2017 Jun 6;114(23):6086-6091. doi: 10.1073/pnas.1621280114. Epub 2017 May 22.

Abstract

The current study identifies CCR8+ regulatory T cells (Treg cells) as drivers of immunosuppression. We show that in human peripheral blood cells, more than 30% of Treg up-regulate CCR8 following activation in the presence of CCL1. This interaction induces STAT3-dependent up-regulation of FOXp3, CD39, IL-10, and granzyme B, resulting in enhanced suppressive activity of these cells. Of the four human CCR8 ligands, CCL1 is unique in potentiating Treg cells. The relevance of these observations has been extended using an experimental model of multiple sclerosis [experimental autoimmune encephalomyelitis, (EAE)] and a stabilized version of mouse CCL1 (CCL1-Ig). First, we identified a self-feeding mechanism by which CCL1 produced by Treg cells at an autoimmune site up-regulates the expression of its own receptor, CCR8, on these cells. Administration of CCL1-Ig during EAE enhanced the in vivo proliferation of these CCR8+ regulatory cells while inducing the expression of CD39, granzyme B, and IL-10, resulting in the efficacious suppression of ongoing EAE. The critical role of the CCL1-CCR8 axis in Treg cells was further dissected through adoptive transfer studies using CCR8-/- mice. Collectively, we demonstrate the pivotal role of CCR8+ Treg cells in restraining immunity and highlight the potential clinical implications of this discovery.

Keywords: CCL1; CD39; EAE; FOXp3; chemokine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chemokine CCL1 / immunology
  • Chemokine CCL1 / metabolism
  • Female
  • Forkhead Transcription Factors / immunology*
  • Forkhead Transcription Factors / metabolism
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Receptors, CCR8 / immunology*
  • Receptors, CCR8 / metabolism
  • T-Lymphocytes, Regulatory / immunology*
  • T-Lymphocytes, Regulatory / metabolism
  • Up-Regulation

Substances

  • CCR8 protein, human
  • Ccr8 protein, mouse
  • Chemokine CCL1
  • FOXP3 protein, human
  • Forkhead Transcription Factors
  • Foxp3 protein, mouse
  • Receptors, CCR8