Archivum Immunologiae et Therapiae Experimentalis

, Volume 56, Issue 1, pp 41–53

Neutrophil recognition of bacterial DNA and Toll-like receptor 9-dependent and -independent regulation of neutrophil function

  • Driss El Kebir
  • Levente József
  • János G. Filep

DOI: 10.1007/s00005-008-0008-3

Cite this article as:
El Kebir, D., József, L. & Filep, J.G. Arch. Immunol. Ther. Exp. (2008) 56: 41. doi:10.1007/s00005-008-0008-3


Neutrophils are essential for host defense and detect the presence of invading microorganisms through recognition of pathogen-associated molecular patterns. Among these receptors are Toll-like receptors (TLRs). Neutrophils express all known TLRs except for TLR3. TLR9, localized intracellularly, is to date the best characterized sensor for bacterial DNA, containing short sequences of unmethylated CpG motifs, though TLR9-independent intracellular DNA recognition mechanism(s) may also exist. Bacterial DNA has profound impact on neutrophil functions; it promotes neutrophil trafficking in vivo, induces chemokine expression, regulates expression of adhesion molecules, enhances phagocyte activity, and rescues neutrophils from constitutive apoptosis. TLR9 stimulation results in alterations in cellular redox balance, peroxynitrite formation, activation of the mitogen-activated protein kinase, PI3-kinase, and Jun N-terminal kinase pathways and/or nuclear factor κB and AP-1. These features identify an important role for bacterial DNA and TLR9 signaling in the regulation of neutrophil functions that are critical for optimal expression as well as for resolution of the inflammatory response.


neutrophilsbacterial DNAToll-like receptor 9apoptosisinflammation



extracellular signal-regulated kinase


IL-1 receptor-associated kinase 4


interferon regulatory factor 5


myeloid differentiation primary response gene 88




phosphoinositide 3-kinase


Toll-like receptor


Z-DNA binding protein 1

Copyright information

© Birkhaueser 2008

Authors and Affiliations

  • Driss El Kebir
    • 1
  • Levente József
    • 1
  • János G. Filep
    • 1
  1. 1.Research Center, Maisonneuve-Rosemont Hospital and Department of Pathology and Cell BiologyUniversity of MontrealMontrealCanada