Fig 1.

IL-12p40 production and surface expression of costimulatory molecules by cDCs in response to L. braziliensis are dependent on TLR9. (A) GM-CSF-derived cDCs from WT and TLR9^−/− mice were stimulated or not with UV-treated L. braziliensis parasites (5:1) (UVLb), LPS, or CpG for 24 h. Supernatants were harvested and assessed for IL-12p40 production by ELISA. Experiments were completed in triplicate; results are means + SEM. ***, P < 0.0005 (Student's t test comparing TLR9^−/− mice to control mice). Data shown are results from 1 experiment and representative of 4 independent experiments. (B) cDCs from WT and TLR9^−/− mice were stimulated or not with UVLb (5:1) for 24 h. DCs were harvested and subjected to flow cytometric analysis. Representative histograms for CD40, CD80, CD86, and MHC-II expression are shown with corresponding quantification calculating the mean MFI + SEM of triplicates from 1 experiment representative of at least 3 independent experiments. Histograms show basal WT expression (gray), cells from WT mice stimulated by L. braziliensis (solid line), and cells from TLR9^−/− mice stimulated by L. braziliensis (dotted line). ***, P < 0.0005; *, P < 0.05 (Student's t test comparing unstimulated DCs to L. braziliensis-stimulated DCs).