Toll-like receptors required for dermatophagoides farinae to activate NF-κB

Biol Pharm Bull. 2014;37(1):74-80. doi: 10.1248/bpb.b13-00595.


Body and excrement extracts from Dermatophagoides farinae were used to study stimulation of Toll-like receptors (TLRs). The excrement extract stimulated nuclear factor (NF)-κB-dependent reporter activity to an extent similar to lipopolysaccharide (LPS) in a mouse macrophage cell line, J774A.1, but the activity of the body extract was negligible. The excrement extract also activated NF-κB in HEK293 cells expressing TLR1/TLR2, TLR2/TLR6 and CD14/TLR4/MD-2, whereas no activation was observed in cells expressing TLR3, TLR5, TLR7, TLR8 or TLR9. Although the excrement extract required co-expression of CD14, TLR4 and MD-2 in HEK293 cells to activate NF-κB, efficient activation was still observed in I-13.35 cells, a bone-marrow macrophage cell line established from LPS-hypo-responsive C3H/HeJ mice. The excrement extract activated NF-κB in HEK293 cells expressing TLR2 alone, but the activation was significantly increased by co-expression of CD14. Polymyxin B inhibited CD14/TLR4/MD-2- and CD14/TLR2-mediated activation of NF-κB but not the activation in I-13.35 cells. These results indicate that CD14/TLR4/MD-2-dependent and CD14/TLR2-dependent mechanisms are involved in the activation of NF-κB by the excrement extract of D. farinae and suggest that the extract also contains substances that activate NF-κB through non-TLR-mediated mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Cell Line
  • Dermatophagoides farinae*
  • HEK293 Cells
  • Humans
  • Hypersensitivity / metabolism*
  • Lipopolysaccharide Receptors / metabolism
  • Lipopolysaccharides
  • Lymphocyte Antigen 96 / metabolism
  • Macrophages / drug effects
  • Macrophages / metabolism*
  • Mice
  • Mice, Inbred C3H
  • NF-kappa B / metabolism*
  • Polymyxin B / pharmacology
  • Toll-Like Receptor 2 / metabolism*
  • Toll-Like Receptor 4 / metabolism*


  • Anti-Bacterial Agents
  • Lipopolysaccharide Receptors
  • Lipopolysaccharides
  • Ly96 protein, mouse
  • Lymphocyte Antigen 96
  • NF-kappa B
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Polymyxin B