Quantitative expression of toll-like receptor 1-10 mRNA in cellular subsets of human peripheral blood mononuclear cells and sensitivity to CpG oligodeoxynucleotides

J Immunol. 2002 May 1;168(9):4531-7. doi: 10.4049/jimmunol.168.9.4531.


The Toll-like receptor (TLR)9 is critical for the recognition of immunostimulatory CpG motifs but may cooperate with other TLRs. We analyzed TLR1-10 mRNA expression by using quantitative real-time PCR in highly purified subsets of human PBMC and determined the sensitivity of these subsets to CpG oligodeoxynucleotides (ODN). TLR1 and TLR6 were expressed in all cell types examined. TLR10 was highly expressed in B cells and weakly expressed in plasmacytoid dendritic cells (PDC). High expression of TLR2 was characteristic for monocytes. PDC and B cells expressed marked levels of TLR7 and TLR9 and were directly sensitive to CpG ODN. In CpG ODN-stimulated PDC and B cells, TLR9 expression rapidly decreased, as opposed to TLR7, which was up-regulated in PDC and decreased in B cells. In monocytes, NK cells, and T cells, TLR7 was absent. Despite low expression of TLR9, monocytes, NK cells, and T cells did not respond to CpG ODN in the absence of PDC but were activated in the presence of PDC. In conclusion, our studies provide evidence that PDC and B cells, but not monocytes, NK cells, or T cells, are primary targets of CpG ODN in peripheral blood. The characteristic expression pattern of TLR1-10 in cellular subsets of human PBMC is consistent with the concept that TLR9 is essential in the recognition of CpG ODN in PDC and B cells. In addition, selective regulation of TLR7 expression in PDC and B cells by CpG ODN revealed TLR7 as a candidate TLR potentially involved in modulating the recognition of CpG motifs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / pharmacology*
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / immunology
  • Blood / immunology
  • Cells, Cultured
  • Clone Cells
  • DNA-Binding Proteins / biosynthesis
  • DNA-Binding Proteins / genetics
  • Dendritic Cells / drug effects
  • Dendritic Cells / immunology
  • Drosophila Proteins*
  • Gene Expression Regulation
  • Humans
  • Immunologic Memory
  • Killer Cells, Natural / drug effects
  • Killer Cells, Natural / immunology
  • Kinetics
  • Leukocytes, Mononuclear / classification
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / immunology*
  • Membrane Glycoproteins / biosynthesis*
  • Membrane Glycoproteins / genetics
  • Monocytes / drug effects
  • Monocytes / immunology
  • Oligodeoxyribonucleotides / pharmacology*
  • Polymerase Chain Reaction
  • Protein Isoforms / biosynthesis
  • Protein Isoforms / genetics
  • RNA, Messenger / biosynthesis
  • Receptors, Cell Surface / biosynthesis*
  • Receptors, Cell Surface / genetics
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology
  • Toll-Like Receptor 1
  • Toll-Like Receptor 10
  • Toll-Like Receptor 2
  • Toll-Like Receptor 7
  • Toll-Like Receptor 9
  • Toll-Like Receptors


  • Adjuvants, Immunologic
  • CPG-oligonucleotide
  • DNA-Binding Proteins
  • Drosophila Proteins
  • Membrane Glycoproteins
  • Oligodeoxyribonucleotides
  • Protein Isoforms
  • RNA, Messenger
  • Receptors, Cell Surface
  • TLR2 protein, human
  • TLR7 protein, human
  • TLR9 protein, human
  • Toll-Like Receptor 1
  • Toll-Like Receptor 10
  • Toll-Like Receptor 2
  • Toll-Like Receptor 7
  • Toll-Like Receptor 9
  • Toll-Like Receptors