Calcium mobilization by IL-8, GRO, NAP-2, and ENA-78 in HMC-1 cells. (A) Kinetics: agonists were added at the time indicated by the arrows. The identity and concentration are indicated to the right of each arrow. (B) Concentration dependence: calcium mobilization was measured in the cells stimulated as indicated. The amplitude of the peak change in fluorescence is shown as a function of the chemokine concentration. Results from one cell experiment are shown. Similar results were obtained in three independent experiments.