Both unmodified and PTO RNA oligonucleotides stimulate bone marrow cells and DCs in a sequence-dependent manner. Murine bone marrow cells or BMDCs were activated for 24 hours with ORNs 9.2dr, 9.2dr PTO, PolyA, or PolyA PTO complexed with DOTAP or with CpG ODN 1826 or LPS. (A) Supernatants were analyzed by ELISA for IL-12p40, IL-6, IFN-α, and IL-10 production. Data show the mean of triplicate samples ± SEM and are representative of at least 2 independent experiments. *P < .001; ns indicates not significant. The asterisk without brackets indicates comparison to unstimulated sample. (B) Surface expression of the activation markers CD80, CD86, CD40, and MHC-II on DCs was measured by fluorescence-activated cell sorting (FACS) after activation of bone marrow cells with ORNs or CpG ODN for 24 hours. Data are expressed as percent of CD11c⁺ cells expressing the respective activation marker and are representative of 2 independent experiments.