Signal transduction pathways mediated by the interaction of CpG DNA with Toll-like receptor 9

Semin Immunol. 2004 Feb;16(1):17-22. doi: 10.1016/j.smim.2003.10.009.


Synthetic oligodeoxynucleotides (ODN) expressing non-methylated "CpG motifs" patterned after those present in bacterial DNA have characteristic immunomodulatory effects. CpG DNA is recognized as a pathogen-associated molecular pattern, and triggers a rapid innate immune response. CpG ODN are being harnessed for a variety of therapeutic uses, including as immune adjuvants, for cancer therapy, as anti-allergens, and as immunoprotective agents. The signal transduction pathway mediated by the engagement of CpG DNA with Toll-like receptor 9 (TLR9) is shared with other members of the TLR family. Recent studies demonstrate that formation and maturation of CpG DNA-containing endosomes are regulated by phosphatidylinositol 3 kinases and the Ras-associated GTP-binding protein, Rab5, which are essential for the initiation of TLR9-mediated signaling.

Publication types

  • Review

MeSH terms

  • Animals
  • CpG Islands / genetics
  • CpG Islands / immunology*
  • DNA, Bacterial / immunology
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / immunology
  • DNA-Binding Proteins / physiology*
  • Endosomes / physiology
  • Gene Expression Regulation
  • Humans
  • Models, Biological
  • Oligodeoxyribonucleotides / immunology
  • Receptors, Cell Surface / genetics
  • Receptors, Cell Surface / immunology
  • Receptors, Cell Surface / physiology*
  • Signal Transduction / genetics
  • Signal Transduction / immunology
  • Signal Transduction / physiology*
  • Toll-Like Receptor 9


  • DNA, Bacterial
  • DNA-Binding Proteins
  • Oligodeoxyribonucleotides
  • Receptors, Cell Surface
  • TLR9 protein, human
  • Toll-Like Receptor 9