ODN 2088 is an effective Toll-like receptor inhibitor exhibiting significant inhibitory activity against TLR3, TLR7, and TLR9 without cytotoxicity. It reduces IFN-α and IL-6 release by blocking associated innate immune signaling pathways. In vitro experiments demonstrated that ODN 2088 (0.01–10 μM, 48 hours) showed minimal inhibition of IL-6 release induced by CpG-ODN 2006 (100 nM), but markedly suppressed IL-6 secretion from human peripheral blood mononuclear cells stimulated by imiquimod (5 μg/mL). This demonstrates its differential regulatory potential across distinct TLR activation pathways.