Characterization of three CpG oligodeoxynucleotide classes with distinct immunostimulatory activities

Eur J Immunol. 2004 Jan;34(1):251-62. doi: 10.1002/eji.200324032.


Oligodeoxynucleotides (ODN) with unmethylated deoxycytidyl-deoxyguanosine (CpG) dinucleotides (CpG ODN) mimic the immunostimulatory activity of bacterial DNA and are recognized by the Toll-like receptor 9 (TLR9). CpG ODN of the B-Class stimulate strong B cell and NK cell activation and cytokine production. The highest degrees of NK stimulation as well as IFN-alpha secretion by plasmacytoid DC were found to occur only with A-Class ODN. A third class of CpG ODN combines the immune effects of A- and B-Class CpG ODN. C-Class ODN strongly stimulate B cell or NK cell activation and IFN-alpha production. In contrast to the A-Class, the C-Class is wholly phosphorothioate, has no poly-G stretches, but has palindromic sequences combined with stimulatory CpG motifs. All classes stimulate TLR9-dependent signaling, but with strikingly different dose-response relationships that are quite in contrast to those observed for IFN-alpha. Effects similar to those on human cells were observed on mouse splenocytes. In contrast, splenocytes from TLR9-deficient mice did not show any response to the three CpG ODN classes. In vivo studies demonstrate that C-Class ODN are very potent Th1 adjuvants. C-Class ODN may represent new therapeutic drugs that combine the effects of A- and B-Class ODN for broad applications in infectious disease or cancer therapy.

MeSH terms

  • Animals
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism*
  • Humans
  • Interferon-alpha / biosynthesis*
  • Membrane Glycoproteins / immunology*
  • Mice
  • NF-kappa B / metabolism
  • Oligodeoxyribonucleotides / classification*
  • Oligodeoxyribonucleotides / immunology
  • Receptors, Cell Surface / immunology*
  • Toll-Like Receptor 9
  • Toll-Like Receptors


  • Interferon-alpha
  • Membrane Glycoproteins
  • NF-kappa B
  • Oligodeoxyribonucleotides
  • Receptors, Cell Surface
  • TLR9 protein, human
  • Toll-Like Receptor 9
  • Toll-Like Receptors