Figure. Concentration-dependent activation of CCR1 by CCL3. Reporter cells were transfected with either the expression plasmid for C-C motif chemo­kine receptor 1 (CCR1) or the mock plasmid and treated with various concentrations of C-C motif chemo­kine ligand 3 (CCL3). 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 250 pM.