Resiquimod

Resiquimod, also known as R-848; S-28463; VML-600, is a n imidazoquinolinamine Toll-like receptor (TLR) agonist with potential immunostimulatory activity. Resiquimod binds to and activates TLRs 7 and 8, mainly on dendritic cells (DCs), macrophages, and B-lymphocytes, which results in the activation of the TLR signaling pathway and nuclear translocation of the transcription activator NF-kB another transcription factors; subsequently, the production of cytokines, especially interferon-alpha (INF-a), increases, enhancing T-helper 1 (Th1) immune responses. In addition, topical application of resiquimod appears to activate Langerhans cells, which may result in enhanced activation of T-lymphocytes.(In Vitro):Resiquimod (R-848) induces both hapten- and allergen-specific circulating T cells, including TH2 effectors, to produce IFN-γ and even to lose the ability to produce IL-4. Resiquimod (R848) enhances PBL proliferation in a dose-dependent manner, and increases the number of BrdU-positive cells in BrdU incorporation assay. Cells treated with R848 exhibits significantly increased (3.5-fold) luciferase (a reporter of NF-κB activity) activity.(In Vivo):Resiquimod (R-848) (50 μg/bird, i.m. route) significantly up-regulates the expression of IFN-α, IFN-β, IFN-γ, IL-1β, IL-4, iNOS and MHC-II genes in SPF chicken.