Figure 4.

Guanosine-rich oligodeoxynucleotide (G-ODN) inhibits human Toll-like receptor 9 (TLR-9) activation. (a) Human peripheral blood mononuclear cells (PBMCs) were incubated with the indicated ODN for 4 hr; mRNA was extracted and the expression of interferon-α (IFN-α) (as an indicator of plasmacytoid dendritic cell stimulation) was quantified by reverse transcription–polymerase chain reaction (RT–PCR). GAPDH, glyceraldehyde 3-phosphate dehydrogenase. (b) PBMCs were stimulated overnight with 0·1 µm CpG 2216 in the presence of G-ODN, as indicated, and IFN-α was quantified by enzyme-linked immunosorbent assay (ELISA) in the supernatant. (c) HEK293 cells transfected with human TLR-9 were stimulated overnight with CpG 2006 in the presence or absence of G-ODN. Interleukin-8 (IL-8) was determined in cell-free supernatant. nd, not determined.