GPR183 (also known as Epstein-Barr virus-induced gene 2) is an orphan G protein-coupled receptor (GPCR) that is highly expressed in spleen and is required for humoral immune responses, including B cell migration and T cell-dependent antibody production.^1,2 7α,25-dihydroxy Cholesterol (7α,25-DHC) is a potent agonist of GPR183 that induces specific activation of the receptor with an EC50 value of 50 nM (Kd = 450 pM).^1,2 At concentrations below 3 μM, it does not show any appreciable binding activity when tested against eight different nuclear hormone receptors including LXR and thirty-one different G protein-coupled receptors in a panel of reporter gene assays.² 7α,25-DHC can act as a potent chemokine, affecting migration of immune cells expressing GPR183 both in vitro (EC50 = 500 pM) and in vivo.^1,2