Influence of calcium, magnesium, lanthanum and A23187 on the aggregation of polymorphonuclear neutrophils

Chemotactic factors transiently aggregate human polymorphonuclear neutrophils. We have found that the aggregation induced by the chemotactic tripeptide, formyl-methionyl-leucyl-phenylalanine, depends on the extracellular calcium and magnesium concentrations and is inhibited by 1 and 10 M lanthanum chloride. The ionophore A23187 and 1 and 0.1 mM lanthanum chloride aggregate the cells. A23187-induced aggregation is dependent on extracellular calcium and magnesium whereas lanthanum-induced aggregation is not.