Leucocyte locomotion and chemotaxis: The influence of divalent cations and cation ionophores

Abstract

Human blood neutrophil leucocytes and monocytes incubated in the absence of Ca 2+ and Mg 2+ showed reduced, but still substantial migration into micropore filters towards chemotactic agents, compared with cells migrating in a divalent cation-rich medium. This reduction in migration could be reversed by adding low doses of divalent cation ionophores (X537A or A23187) to the Ca 2+- and Mg 2+-free medium which suggests that migrating leucocytes in media depleted of extracellular divalent cations can make use of intracellular divalent cations and that the intracellular cation exchange necessary for locomotion is facilitated by the ionophores. At higher doses, the ionophores inhibited locomotion, as did procaine which reduces membrane permeability to cations. Little effect of K + depletion or of ouabain on leucocyte locomotion was noted.