Description
Loxoribine is a guanosine derivative and an agonist of toll-like receptor 7 (TLR7). It is selective for TLR7 over other human TLRs in a cell-based reporter assay at 1 mM.. Loxoribine induces proliferation, increases the antibody response to sheep red blood cells, and activates natural killer cell activity against Yac-1 lymphoma cells in murine splenocyte cultures (EC50s = 10-50, 3-20, and 13-22 μM, respectively). Loxoribine (250 μM) increases production of IL-12, IL-23, IL-27, and IL-10 by human monocyte-derived dendritic cells (MoDCs). Loxoribine-treated MoDCs induce higher levels of IL-17 and IFN-γ secretion by co-cultured allogeneic CD4+ T cells compared to control MoDCs. Loxoribine (120 mg/kg) reduces the number of pulmonary metastases in the B16 mouse model of melanoma, an effect enhanced by co-administration of IL-2, and exhibits adjuvant activity in mice immunized with a B16 tumor vaccine.
Chemical Properties
White Solid
Uses
7-Allyl-7,8-dihydro-8-oxoguanosine (Loxoribine) is a small-molecule immunostimulant. Loxoribine is a toll-like receptor 7 (TLR7) agonist; induces immune cell activation and increases cytokine product
ion. Loxoribine displays antitumor and antiviral activity in various animal models.
Uses
Small-molecule immunostimulants
Biological Activity
Toll-like receptor 7 (TLR7) agonist; induces immune cell activation and increases cytokine production. Displays antitumor and antiviral activity in various animal models.
References
1) Heil?et al.?(2003),?The Tool-like receptor 7 (TLR7)-specific stimulus loxoribine uncovers a strong relationship within the TLR7, 8 and 9 subfamily; Eur. J. Immunol.,?33?2987
2) Goodman?et al.?(1995),?A new approach to vaccine adjuvants. Immunopotentiation by intracellular T-helper-like signals transmitted by loxoribine;?Pharm. Biotechnol.,?6?581
3) Girart?et al.?(2007), Engagement of TLR3, TLR7 and NKG2D regulate IFN-gamma secretion but not NKG2D-mediated cytotoxicity by human NK cells stimulated with suboptimal doses of IL-12; J. Immunol.,?179?3472
4) Stewart?et al.?(2012),?Toll-like receptor 7 ligands inhibit influenza A infection in chickens; J. Interferon Cytokine Res,,?32?46
5) Wang?et al.?(2015),?The TLR7 agonist induces tumor regression both by promoting CD4-T cells proliferation and by reversing T regulatory cell-mediated suppression via dendritic cells; Oncotarget,?6?1779
