Limited contribution of Toll-like receptor 2 and 4 to the host response to a fungal infectious pathogen, Cryptococcus neoformans

FEMS Immunol Med Microbiol. 2006 Jun;47(1):148-54. doi: 10.1111/j.1574-695X.2006.00078.x.

Abstract

The present study was designed to elucidate the role of Toll-like receptor (TLR) 2 and TLR4 in the host response to Cryptococcus neoformans. Both TLR2 knockout (KO) and TLR4KO mice produced interleukin-1beta (IL-1beta), IL-6, IL-12p40 and tumor necrosis factor-alpha (TNF-alpha) in sera and cleared this fungal pathogen from infected lungs at a comparable level to control littermate (LM) mice. Synthesis of these cytokines was not significantly different in the lungs of these KO mice and LM mice, although IL-1beta, IL-6 and IL-12p40 tended to be lower in TLR2KO, but not TLR4KO, mice than in controls. In addition, there was no significant reduction detected in the synthesis of IL-12 and TNF-alpha by bone marrow-derived dendritic cells from TLR2KO and TLR4KO mice upon stimulation with live yeast cells. Finally, HEK293 cells expressing either TLR2/dectin-1 or TLR4/MD2/CD14 did not respond to C. neoformans in the activation of nuclear factor kappa B (NFkappaB) detected by a luciferase assay. Our results suggest that TLR2 and TLR4 do not or only marginally contribute to the host and cellular response to this pathogen.

MeSH terms

  • Animals
  • Cryptococcosis / immunology*
  • Cryptococcus neoformans / immunology*
  • Dendritic Cells / immunology
  • Female
  • Interleukin-1 / biosynthesis
  • Interleukin-1 / immunology
  • Interleukin-12 / biosynthesis
  • Interleukin-12 / immunology
  • Interleukin-12 Subunit p40
  • Interleukin-6 / biosynthesis
  • Interleukin-6 / immunology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Protein Subunits / biosynthesis
  • Protein Subunits / immunology
  • Toll-Like Receptor 2 / deficiency
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / immunology*
  • Toll-Like Receptor 4 / deficiency
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / immunology*
  • Transfection
  • Tumor Necrosis Factor-alpha / biosynthesis
  • Tumor Necrosis Factor-alpha / immunology

Substances

  • Interleukin-1
  • Interleukin-12 Subunit p40
  • Interleukin-6
  • Protein Subunits
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Tumor Necrosis Factor-alpha
  • Interleukin-12