Human blood mDC subsets exhibit distinct TLR repertoire and responsiveness

J Leukoc Biol. 2013 Apr;93(4):599-609. doi: 10.1189/jlb.0912452. Epub 2013 Jan 22.

Abstract

Human blood DCs encompass pDCs and two subsets of mDCs: CD1c(+) mDCs and CD141(+) mDCs. The rare CD141(+) DC population is thought to be the equivalent of mouse CD8α(+) cDCs that play a significant role in antigen cross-presentation. Here, we analyzed by Q-PCR TLR1-10 expression in blood DC subsets. Whereas CD1c(+) DCs express all TLR except TLR9, CD141(+) DCs present a more restricted pattern with high expression of TLR3 and -10, expression of TLR1,-2, -6, and -8, and lack of TLR4, -5, -7, and -9. The in vitro analysis of isolated mDC subset reponsiveness to an extensive panel of TLR ligands confirmed these results, with CD141(+) DCs responding only to TLR1/2, -3, and -7/8. The cytokine/chemokine production profile of isolated CD141(+) DCs was also more restricted, as they produced mainly proinflammatory cytokines but no IL-12 and to a lower level, in comparison with CD1c(+) DCs, except for CXCL10, CCL5, and IFN-β. In contrast, with the use of a whole blood assay, we found that CD141(+) DCs produce IL-12 in response to TLR1/2, -3, and more surprisingly, -9. Finally, both mDC subsets are potent inducers of Th1 response, particularly after TLR3 triggering. Taken together, these data confirmed functional differences between blood mDC subsets. The major response of CD141(+) mDCs to TLR3 ligand and their cytokine production pattern suggest a role for these cells in antiviral immunity.

MeSH terms

  • Antigen Presentation
  • Antigens, CD / genetics
  • Antigens, CD / immunology*
  • Antigens, CD1 / genetics
  • Antigens, CD1 / immunology
  • Cells, Cultured
  • Cytokines / immunology*
  • Cytokines / metabolism
  • Dendritic Cells / classification
  • Dendritic Cells / cytology
  • Dendritic Cells / immunology*
  • Flow Cytometry
  • Glycoproteins / genetics
  • Glycoproteins / immunology
  • Humans
  • Immunomagnetic Separation
  • Immunophenotyping
  • Protein Isoforms / classification
  • Protein Isoforms / genetics
  • Protein Isoforms / immunology
  • Toll-Like Receptors / classification
  • Toll-Like Receptors / genetics
  • Toll-Like Receptors / immunology*

Substances

  • Antigens, CD
  • Antigens, CD1
  • CD1C protein, human
  • Cytokines
  • Glycoproteins
  • Protein Isoforms
  • Toll-Like Receptors