Figure. Concentration-dependent activation of CXCR1 by CXCL6. Reporter cells were transfected with either the expression plasmid for C-X-C motif chemo­kine receptor 1 (CXCR1) or the mock plasmid and treated with various concentrations of C-X-C motif chemo­kine ligand 6 (CXCL6). 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 20 nM.