Figure 6.

RvE1 regulates DCs. (a) RvE1 inhibits DC IL-12 production in vitro stimulated by pathogen extract (STAg). CD11c⁺ DCs incubated with vehicle (open circles) or RvE1 (closed circles) before STAg or no STAg (open squares). (b) Reduction of ChemR23 expression by siRNA eliminates RvE1 signaling. Expression of ChemR23 and GAPDH mRNA from DCs treated with either scramble or ChemR23-specific siRNAs (inset). Spleen cells transfected with siRNAs were treated with vehicle (ethanol, 0.1% vol/vol) or RvE1 (1.0 μg/ml). 8 h later, cells were stimulated with 10 μg/ml STAg and IL-12p40 was measured. Bars represent mean ± SD (n = 3), *, P < 0.05 (control vs. specific siRNA). (c) RvE1 blocks IL-12 production in vivo. Mice administered with either 100 ng RvE1 or vehicle were challenged intraperitoneally with PBS or STAg, and IL-12p40 secretion from splenic CD11c⁺ DCs was measured. (d–g) RvE1 blocks trafficking of CD11c⁺ DCs in spleen with pathogen extract challenge. Spleens from mice given 10 μg RvE1 or vehicle were stained for CD11c. (d) PBS plus vehicle (e) STAg plus vehicle (f) PBS plus RvE1 (g) STAg plus RvE1. Arrows indicate CD11c positive DCs accumulated in T cell–enriched area.