A quantitative study of leukocyte cohesion: effects of divalent cations and pH

Leukocyte cell-to-cell adhesion was studied with a cell monolayer technique. The amount of protein retained on the coverslip reflected the number of adhering cells. When polymorphonuclear leukocytes were suspended in a balanced salt solution at neutral pH containing no bivalent cations, they adhered to the glass surface but not to each other. Magnesium or calcium at concentrations above 1 mM caused cell-to-cell adhesion. Stannous and chromate ions had no effect on leukocyte cell-to-cell adhesion. Acid pH also induced leukocyte aggregation. This last effect could be reversed by washing the cells with a balanced salt solution at neutral pH, but it could not be reversed by alcohol.