Mizoribine is an imidazole nucleoside with immunosuppressive properties.
1 It inhibits T cell proliferation in response to various mitogenic stimuli by 10-100% when used at concentrations ranging from 1 to 50 μg/mL. Mizoribine inhibits proliferation of stimulated T cells (IC
50 = 5 μg/ml), which can be reversed by guanosine.
2 It also inhibits guanine nucleotide formation in T cells, reducing GTP pools by 40-60% when used at a concentration of 5 μg/ml. Mizoribine inhibits replication of hepatitis C virus (HCV) RNA
in vitro (IC
50 = 100 μM).
3 It suppresses glomerulosclerosis, urinary albumin excretion, interstitial fibrotic lesions, and macrophage infiltration into glomeruli and the interstitium in a rat model of type 2 diabetes when used at doses of 5 or 10 mg/kg.
4 Mizoribine also reduces MCP-1, osteopontin (OPN), and TGF-β1 mRNA expression in the kidney in the same model. Formulations containing mizoribine have been used for the prevention of rejection after renal transplantation as well as in the treatment of lupus nephritis, rheumatoid arthritis, and primary nephritic syndrome.