Figure 3.

Impact of 2′-O-ribose methylation on cytokine induction by naturally methylated and unmethylated sequences. (a) Sequences of applied RNA derivatives. 2′-O-ribose methylated guanosine are indicated with an X. (b,c) PBMCs were stimulated with RNA66 or RNA28 derivatives at a final concentration of 10 µg/mL, with 1 µM CpG ODN 2216 or 5 µg/mL RNA40. Supernatants were harvested 20 h p. s. and both (b) IFN-α and (c) IL-6 concentrations were measured by ELISA. Graphs depict six independent experiments with PBMCs obtained from six individual healthy donors each in biological duplicates (twelve measurements per data point, mean + S.D). Data were analyzed using paired t-tests; IL-6-data of RNA66 and RNA66M were analyzed using Wilcoxon tests. **** p < 0.0001, *** p < 0.001, ** p < 0.01.