Enhancement of infectious disease vaccines through TLR9-dependent recognition of CpG DNA

Curr Top Microbiol Immunol. 2006;311:155-78. doi: 10.1007/3-540-32636-7_6.


The adaptive immune system-with its remarkable ability to generate antigen-specific antibodies and T lymphocytes against pathogens never before "seen" by an organism-is one of the marvels of evolution. However, to generate these responses, the adaptive immune system requires activation by the innate immune system. Toll-like receptors (TLRs) are perhaps the best-understood family of innate immune receptors for detecting infections and stimulating adaptive immune responses. TLR9 appears to have evolved to recognize infections by a subtle structural difference between eukaryotic and prokaryotic/viral DNA; only the former frequently methylates CpG dinucleotides. Used as vaccine adjuvants, synthetic oligodeoxynucleotide (ODN) ligands for TLR9--CpG ODN--greatly enhance the speed and strength of the immune responses to vaccination.

Publication types

  • Review

MeSH terms

  • Adjuvants, Immunologic*
  • Animals
  • B-Lymphocytes / immunology
  • Bacterial Infections / immunology
  • CpG Islands / immunology*
  • DNA, Bacterial / genetics
  • DNA, Viral / genetics
  • DNA, Viral / metabolism
  • Humans
  • Immunity, Active*
  • Ligands
  • Oligodeoxyribonucleotides / chemical synthesis
  • Oligodeoxyribonucleotides / genetics
  • Oligodeoxyribonucleotides / immunology
  • Toll-Like Receptor 9 / immunology*
  • Toll-Like Receptor 9 / metabolism
  • Vaccines / immunology*
  • Virus Diseases / immunology


  • Adjuvants, Immunologic
  • DNA, Bacterial
  • DNA, Viral
  • Ligands
  • Oligodeoxyribonucleotides
  • Toll-Like Receptor 9
  • Vaccines