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. 2007 Jun;75(6):3205-8.
doi: 10.1128/IAI.01950-06. Epub 2007 Mar 19.

Legionella pneumophila infection up-regulates dendritic cell Toll-like receptor 2 (TLR2)/TLR4 expression and key maturation markers

James Rogers  1 , Amal Hakki, Izabella Perkins, Catherine Newton, Ray Widen, Nicholas Burdash, Thomas Klein, Herman Friedman
Affiliations

Legionella pneumophila infection up-regulates dendritic cell Toll-like receptor 2 (TLR2)/TLR4 expression and key maturation markers

James Rogers et al. Infect Immun. 2007 Jun.

Abstract

Dendritic cells (DCs) have a critical role in linking innate to adaptive immunity, and this transition is regulated by the up-regulation of costimulatory and major histocompatibility complex (MHC) molecules as well as Toll-like receptors. These changes in DCs have been observed to occur following microbial infection, and in the present study, we examined the effect of Legionella pneumophila infection on the expression of these DC markers. We showed that bone marrow-derived DC cultures from BALB/c mice infected with live L. pneumophila resulted in the up-regulation of Toll-like receptors 2 and 4 and the activation of CD40, CD86, and MHC class I/II molecules.

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Figures

FIG. 1.
FIG. 1.
Legionella infection up-regulates MHC-I/MHC-II and costimulatory molecule expression on DCs. Flow cytometric dot plots of CD11c and costimulatory/MHC surface molecule expression. DCs were infected at 10 bacteria per cell and cultured at 1 × 106 cells/ml. Numbers in quadrants reflect percentages rounded to the next greatest whole integer. Results are representative of one of five independent experiments with similar results. Lp, L. pneumophila; FL, fluorochrome.
FIG. 2.
FIG. 2.
Legionella infection up-regulates TLR2/TLR4 surface expression on DCs. DCs were infected at 10 bacteria per cell and cultured at 1 × 106 cells/ml. (A) Flow cytometric dot plots of CD11c and TLR2/TLR4 surface molecule expression. Numbers in quadrants reflect percentages rounded to the next greatest whole integer. The results shown are representative of one of three independent experiments with similar results. (B) Bar graphs of the percentage of CD11c+ and TLR2/TLR4 surface molecule expression. Data represent means ± standard deviations from three independent experiments. Asterisks indicate statistically significant differences (P < 0.05 compared to non-L. pneumophila-infected cells). Lp, L. pneumophila; FL, fluorochrome.
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