Non-CpG ssDNA-ODNs inhibit poly I:C–induced DC maturation. (A-C) DC maturation was determined in cultures with poly I:C and ssDNA-ODN with (A) a non-CpG sequence (data are shown as MFI mean ± SEM for 11 donors), (B) a phosphorodiester (PD) backbone (MFI mean ± SEM are shown for 12 donors), or (C) different classes of ODNs (MFI mean ± SEM are shown for 10 donors). Significant differences after poly I:C stimulation compared with and without ssDNA-ODNs were assessed by repeated measures ANOVA with Bonferroni Multiple Comparison and are indicated by **P < .01 and ***P < .001, respectively. NS indicates nonsignificant.