SSL5 inhibits actin polymerization and chemotaxis by chemokines and anaphylatoxins. (A-C) Neutrophils were incubated for 1 minute with (▴) or without (■) 30 μg/mL SSL5 and stimulated with 3 nM fMLP (A), 10 nM CXCL8 (B), or 1 nM C5a (C) for 5 minutes. At several time points samples were taken, and actin polymerization was measured. Results are expressed as the relative increase in fluorescence compared with unstimulated cells. (D,E) Neutrophils were incubated with (♦) or without (■) 10 μg/mL SSL5 and allowed to migrate toward fMLP (D) or CXCL8 (E). Chemotaxis was measured after 30 minutes. Results represent mean plus or minus SEM of 3 independent experiments.