Figure 3.

Uric acid and the inhibition of DC maturation by P. yoelii-infected erythrocytes. (A) DCs were incubated alone (Control) or in the presence of various concentrations of hypoxanthine for 24 h followed by an additional 24 h in the absence (grey bars) or presence (black bars) of 100 ng/ml LPS. Results are expressed as the relative increase in MFI over DCs incubated in media alone. Error bars represent the standard deviation of 3 averaged independent experiments. (B, C) DCs were incubated alone (Control) or with uninfected RBCs (RBCs) or P. yoelii-infected erythrocytes (iRBCs). (B) 2 mM allopurinol was added or not to the co-cultures for 24 h followed by an additional 24 h in the presence or absence of 100 ng/ml LPS. (C) Co-cultures were incubated alone for 24 h before addition of uric acid crystals for additional 24 h. FACS plots show CD40 or CD86 surface expression on DCs from control cultures (gray filled histogram) or incubated with LPS (B) or uric acid crystals (C) (black thick line). Mean fluorescent intensity (MFI) values are indicated in each plot for control and stimulated. Each FACS plot is representative of one of at least 2 independent experiments.