Effect of CP-532,903 on neutrophil chemotaxis in trans-well migration assays using Percoll gradient purified mouse bone marrow neutrophils. Fluorescently labeled (Calcein-AM) neutrophils were added into upper wells, with fMLP and/or CP-532,903 in the lower wells in the presence of ADA (1 unit/mL), separated by a polycarbonate membrane. After incubating at 37° C for 35 min, migrated cells were quantified and chemotaxis was calculated as described in Methods. (A) Effect of adding increasing concentrations of CP-532,903 into lower wells. (B) Effect of adding increasing concentration of CP-532,903 into bottom wells on fMLP-induced (1 μM) chemotaxis of unprimed and TNF-αprimed neutrophils. Results are presented as the mean ± SEM. n = 3–5.