A single naturally occurring 2'-O-methylation converts a TLR7- and TLR8-activating RNA into a TLR8-specific ligand

PLoS One. 2015 Mar 18;10(3):e0120498. doi: 10.1371/journal.pone.0120498. eCollection 2015.


TLR7 and TLR8 recognize RNA from pathogens and lead to subsequent immune stimulation. Here we demonstrate that a single naturally occurring 2'-O-methylation within a synthetic 18s rRNA derived RNA sequence prevents IFN-α production, however secretion of proinflammatory cytokines such as IL-6 is not impaired. By analysing TLR-deficient plasmacytoid dendritic cells and performing HEK293 genetic complementation assays we could demonstrate that the single 2'-O-methylation containing RNA still activated TLR8 but not TLR7. Therefore this specific 2'-O-ribose methylation in rRNA converts a TLR7/TLR8 ligand to an exclusively TLR8-specific ligand. Interestingly, other modifications at this position such as 2'-O-deoxy or 2'-fluoro had no strong modulating effect on TLR7 or TLR8 activation suggesting an important role of 2'-O-methylation for shaping differential TLR7 or TLR8 activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • HEK293 Cells
  • Humans
  • Interferon-alpha / biosynthesis
  • Interleukin-6 / metabolism
  • Ligands
  • Methylation
  • Mice
  • RNA / chemistry*
  • RNA / metabolism*
  • RNA, Ribosomal, 18S / metabolism
  • Substrate Specificity
  • Toll-Like Receptor 7 / metabolism*
  • Toll-Like Receptor 8 / metabolism*


  • Interferon-alpha
  • Interleukin-6
  • Ligands
  • RNA, Ribosomal, 18S
  • Toll-Like Receptor 7
  • Toll-Like Receptor 8
  • RNA

Grants and funding

SB was funded by Transregio-84, the German Center for Infection Research (DZIF), SFB1021, DFG grant BA 1618/5-1 and grant 56-0034 from the Behring Röntgen Stiftung. SJ was funded by the German National Academic Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.