RNase sensitivity of U1snRNP induced FL-DC activation. FL-DCs (untreated or pretreated with IFN-β) were incubated with untreated or RNAse-treated poly-U and U1snRNP (20 μg/mL) in complex with DOTAP (12.5 μg/mL) or Y12 antibody (50 μg/mL). Cytokine production was measured by ELISA, and CD86 expression (expressed as mean fluorescence intensity) was determined by flow cytometry. Mean values and standard deviations (error bars) are shown (n = 3). Asterisks indicate significant differences between conditions with and without RNAse treatment (P < .05; 2-tailed paired Student t test).