Lead interference in actin redistribution induced by chemotactic peptide in human neutrophils

By Governa, M. - Visona, I. - Valentino, M. - Marchiseppe, I.

The distribution of actin-containing structures in vitro was determined by fluorescence microscopy in human neutrophils exposed to two final concentrations of lead, 14.4 micromoles ad 28.8 micromoles, stimulated with 10(-8) M formyl methyonylleucylphenylalanine (F-MLP) for either 45 seconds or 10 minutes, and then stained with phalloidin labelled with rhodamine. The comparison between untreated and lead-treated cells revealed that actin redistribution does not regularly occur within neutrophils in lead-containing medium. Immediately after F-MLP stimulation, no focal subcortical localisation of actin was observed. 10 minutes after stimulation, the redistribution of actin was considerably lower in the lead-treated cells than the redistribution which occurred within untreated cells. Moreover, the polarisation of neutrophils supplemented with lead was abortive. Since previous investigations indicated that lead inhibits chemotaxis of neutrophils, these results suggest that one possible cause of this inhibition is related to an effect of lead on actin reorganisation within the cells.