FIGURE 3

2'-O-methyl (2'OMe) single-stranded RNA (ssRNA) inhibits loxoribine-mediated interferon- (IFN-)and interleukin-6 (IL-6) production in both human and murine systems in vitro. Cytokine responses from (a, b) human peripheral blood mononuclear cells or (c, d) murine Flt3L dendritic cells treated with the TLR7 agonist loxoribine at 300 mol/l or 30 mol/l, respectively. Cells were treated simultaneously with soluble loxoribine plus either medium alone, lipid vehicle (lipid), or lipid-formulated native ssRNA (GFP-S) or 2'OMe RNAs [Luc-mU or (mU)₂₁] for 24 hours before secreted (a, c) IFN- and (b, d) IL-6 were assayed. Control cultures received phosphate-buffered saline (PBS) vehicle only; RNA was added at 0.2 mol/l (1.4 g/ml) final concentration. Data reflect mean cytokine levels + SD of triplicate cultures and are representative of at least two independent experiments. GFP, green flourescent protein.