The effect of metal ions on neutrophil degranulation

This study examined neutrophil activation, after incubation of these cells with metal ions. Activation was examined using lysozyme and chemiluminescence assays. Cobalt ions (0.5–30 p.p.m.), chromium ions (0.5–20 p.p.m.), nickel ions (1–50 p.p.m.) and aluminium ions (0.05–7.5 p.p.m.) did not stimulate neutrophils to release lysozyme and did not stimulate a respiratory burst. Copper ions (0.25–7.5 p.p.m.) stimulated neutrophils to release lysozyme, a result which was significant at the 5% level. This was not as a result of copper ions causing neutrophils to lyse. Lysozyme secretion was inhibited when neutrophils were pre-incubated with cytochalasin B, although cytochalasin B had no effect on the enzyme secretion due to stimulation by opsonized zymosan and zymosan-activated serum. This suggests that the mechanism by which copper ions stimulate neutrophil degranulation is different from that of opsonized zymosan and zymosan-activated serum. Enzyme secretion was not accompanied by a respiratory burst.