Figure. Concentration-dependent activation of CCR2 by CCL2. Reporter cells were transfected with either the expression plasmid for C-C motif chemo­kine receptor 2 (CCR2) or the mock plasmid and treated with various concentrations of C-C motif chemo­kine ligand 2 (CCL2). Data points shown are the mean ± SEM of an experiment performed in triplicate, and the curve is a fit to Hill equation with an EC50 of 1.3 nM.