7α, 25-dihydroxycholesterol (7α,25-OHC) is a potent and selective agonist and endogenous ligand of the orphan GPCR receptor EBI2 (GPR183). 7α, 25-dihydroxycholesterol is highly potent at activating EBI2 (EC50=140 pM; Kd=450 pM). 7α, 25-dihydroxycholesterol can serve as a chemokine directing migration of B cells, T cells and dendritic cells.