LTA-triggered rapid increase in intracellular calcium does not block chemokine-induced CCR2- and CCR5-mediated calcium flux. Monocytes loaded with Fluo-8 AM were stimulated with LTA alone, in the presence of 2mM EGTA, or treated with 10μM U73122, and changes in the intracellular calcium concentration were determined by analysis of the fluorescence of the cells on a CyAn flow cytometer with the use of an argon laser at a wavelength of 488 nm (A). Similar experiments were carried out for cells stimulated with chemokines alone (B) or after short-term (C) or long-term (D) preexposure to 10 μg/mL LTA. Data are expressed as changes in the mean fluorescence intensity (MFI) of Fluo-8–loaded cells over time and are representative of 3 (A) to 5 (B-D) independent experiments.