Resiquimod (R-848) is an immunomodulatory small molecule structurally related to imiquimod It functions primarily by activating immune responses via inducing cytokine release In vitro studies with human peripheral blood mononuclear cells (PBMC) indicate that Resiquimod promotes dose-dependent production of cytokines including interferon-alpha (IFN- ) tumor necrosis factor (TNF) interleukin-1 (IL-1 ) and interleukin-6 (IL-6) Mechanistically Resiquimod increases intracellular IL-1 levels and both monocytes and B-cells respond by secreting IFN upon stimulation In addition it elevates mRNA expression of IFN- TNF and IL-8 in treated PBMC relative to untreated controls Resiquimod demonstrates antiviral and antitumor activities in preclinical animal models frequently utilized as an immune response potentiator and Toll-like receptor (TLR) agonist in biomedical investigations (IC50 values typically range in low micromolar)