Salp15 Binding to DC-SIGN Inhibits Cytokine Expression by Impairing both Nucleosome Remodeling and mRNA Stabilization
Figure 1
Salp15 and Ixodes Tick Saliva Do Not Affect DC Maturation, but Dose-Dependently Inhibit IL-12, IL-6, and TNF-α Production
(A) Salp15 does not interfere with DC maturation. Immature DCs were stimulated with Salp15 or tick saliva alone in the presence or absence of 10 ng/ml LPS. 18 h post-stimulation DCs were analysed by flow cytometry (FACS) for surface expression of maturation markers CD80, CD83, and CD86. The thin lines represent DCs incubated without LPS and the bold lines those of DCs incubated with LPS. The isotype control is depicted in the left three graphs.
(B and C) Salp15 inhibits pro-inflammatory cytokine production by DCs. Immature DCs were stimulated with control medium (white bars), Salp15 (50, 25, or 12.5 μg/ml; black bars) in the presence of 10 ng/ml LPS. As a control, immature DCs were incubated with control buffer or Salp15 (25 μg/ml) in the absence of LPS. Supernatants were analyzed after 18 h for cytokine production (B), and for isolation of mRNA cells were lysed after 6 h of incubation and cytokine gene expression was measured by quantitative real time PCR. LPS was set at 1 (C).
(D) Tick saliva inhibits pro-inflammatory cytokines by DCs. Immature DCs were treated with tick saliva (dilutions of 1:75, 1:150, and 1:300; black bars) in the presence of 10 ng/ml LPS as described in (B).
For (B) and (D) bars represent the average of duplicates or triplicates from one experiment ± SE. The results are representative of at least three independent experiments. For (C) bars represent the mean of four to six independent experiments ± SE. Differences in cytokine production by DCs stimulated with LPS and DCs stimulated with LPS in the presence of Salp15 or tick saliva were analyzed by a two-sided one way ANOVA, implementing a one way analysis of variance and a Dunnett multiple comparison test. A p-value < 0.05 was considered statistically significant. (*) 0.01 < p < 0.05; two asterisks (**) 0.001 < p < 0.01.