Influence of rifampicin and ansamycin on motility and adherence of human neutrophils studied in vitro.

We have studied the influence of rifampicin and ansamycin on chemotaxis, random migration and adherence to plastic of human neutrophils. Neutrophils were preincubated for 30 min at 37 degrees C with the antibiotics. Chemotaxis was studied in antibiotic-free and antibiotic-containing agar using zymosan-activated serum and fMLP as stimuli. Adherence was studied in plastic microtitre plates. Rifampicin and LM427 (ansamycin, 6 mg/l) did not impair differential migration, but inhibited random migration. At clinically achievable concentration (greater than or equal to 6 mg/l), inhibition was less than or equal to 18%. The chemokinetic response curve induced by different concentrations of fMLP was not modified by the two antibiotics. Adherence to polystyrene was significantly increased and could explain the inhibition of random migration.