TLR agonists induce regulatory dendritic cells to recruit Th1 cells via preferential IP-10 secretion and inhibit Th1 proliferation

Blood. 2007 Apr 15;109(8):3308-15. doi: 10.1182/blood-2006-08-040337. Epub 2006 Dec 14.

Abstract

Dendritic cells (DCs) and chemokines are important mediators linking innate and adaptive immunity on activation by Toll-like receptor (TLR) agonists. We previously identified a kind of regulatory DC subset (diffDCs) that differentiated from mature DCs under splenic stroma and that inhibited T-cell proliferation. The responsiveness of such regulatory DCs to TLR agonists and their pattern of chemokine production remain to be determined. Here, we report that the regulatory DCs secrete a higher level of CXCR3 chemokine IFN-gamma-induced protein-10 (IP-10) than immature DCs (imDCs), and more IP-10 is produced after stimulation with TLR-2, -4, -3, and -9 ligands. Blockade of IFN-alpha/beta inhibits IP-10 production by TLR agonist-activated regulatory DCs. We show that the increased IRF-3 and IFN-beta-induced STAT1 activation are responsible for the autocrine IFN-beta-dependent preferential production of IP-10 by regulatory DCs. In addition, stimulation with recombinant mouse IFN-alpha/beta induces more IP-10 production in regulatory DCs than that in imDCs. Moreover, the regulatory DCs selectively recruit more Th1 cells through IP-10 and inhibit Th1 proliferation. Our results demonstrate a new manner for regulatory DCs to down-regulate T-cell response by preferential IP-10 production and inhibition of recruited Th1 cell proliferation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Cell Proliferation / drug effects*
  • Cells, Cultured
  • Chemokine CXCL10
  • Chemokines, CXC / immunology
  • Chemokines, CXC / metabolism*
  • Dendritic Cells / immunology
  • Dendritic Cells / metabolism*
  • Interferon Regulatory Factor-3 / immunology
  • Interferons / immunology
  • Interferons / pharmacology
  • Lipopolysaccharides / pharmacology*
  • Mice
  • Spleen / immunology
  • Stromal Cells / immunology
  • Th1 Cells / immunology*
  • Th1 Cells / metabolism
  • Toll-Like Receptors / agonists*
  • Toll-Like Receptors / immunology

Substances

  • Chemokine CXCL10
  • Chemokines, CXC
  • Interferon Regulatory Factor-3
  • Irf3 protein, mouse
  • Lipopolysaccharides
  • Toll-Like Receptors
  • Interferons