Alteration of polymorphonuclear leukocyte surface charge by endogenous and exogenous chemotactic factors

We investigated the effects of chemotaxins on the surface charge of isolated human PMN. Chemotaxis was ascertained using Boyden chambers. Surface charge was calculated using data derived from cell mobility as measured in a cytophorometer. The electrophoretic mobility of cells exposed to all chemotactic agents studied was altered. Endotoxin-activated serum containing C5a, PMN lysosomal extracts from "resting" and from crystal-stimulated cells, and Gly-His-Gly, a synthetic tripeptide, all significantly reduced the net negative surface charge of isolated neutrophils. Only chemotactically active substances effected this change; controls including heat-inactivated serum, other subcellular fractions, and an inert tripeptide, Gly-Gly-Gly, did not alter cell mobility in an electric field. These findings are consistent with studies by others on the effects of chemotactic factors on cation fluxes and cell aggregation and suggest a possible mechanism by which PMN directional migration is regulated.