Redundant role of TLR9 for anti-Candida host defense

Immunobiology. 2008;213(8):613-20. doi: 10.1016/j.imbio.2008.05.002. Epub 2008 Jun 26.

Abstract

The role of Toll-like receptor-9 (TLR9) in the recognition of Candida albicans and anti-Candida host defense was investigated in a murine model of disseminated candidiasis and in human peripheral blood mononuclear cells (PBMC). Blocking TLR9 by a specific inhibitor of human TLR9 or stimulation of cells isolated from TLR9-deficient (TLR9-/-) mice resulted in a 20-30% reduction in cytokine production induced by C. albicans. However, this defect was not accompanied by differences in mortality and organ fungal growth between TLR9-/- and TLR9+/+ mice. In conclusion, TLR9 is a pathogen-recognition receptor for C. albicans, and TLR9 is involved in the induction of cytokines in response to C. albicans. However, the cytokine defect in TLR9-/- mice is compensated by alternative pathways, and the TLR9-dependent pathway seems to be redundant in the disseminated candidiasis model in mice.

MeSH terms

  • Animals
  • Candida albicans*
  • Candidiasis / immunology*
  • Cytokines / metabolism
  • Cytotoxicity, Immunologic / genetics
  • Humans
  • Immunity, Innate
  • Leukocytes, Mononuclear / metabolism*
  • Lymphocyte Activation / genetics
  • Macrophages, Peritoneal / immunology
  • Macrophages, Peritoneal / metabolism*
  • Macrophages, Peritoneal / pathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Oligonucleotides, Antisense / genetics
  • Phagocytosis / genetics
  • Phagocytosis / immunology
  • Toll-Like Receptor 9 / antagonists & inhibitors
  • Toll-Like Receptor 9 / genetics
  • Toll-Like Receptor 9 / immunology*

Substances

  • Cytokines
  • Oligonucleotides, Antisense
  • Toll-Like Receptor 9