Alterations of the oxidative metabolism and other microbicidal activities of human polymorphonuclear leukocytes by zinc.

Zinc is a physiological constituent of many human enzymes and also involved in an optimal immune response. Zinc deficiency as well as excessive zinc supplementation lead to disturbed functions of immune cells. In this study with isolated human polymorphonuclear leukocytes the toxic oxygen species generated during the oxidative metabolism were enhanced in presence of zinc ions. However, when the generation of superoxide anion was measured alone it was decreased by zinc. The phagocytic capacity was diminished in presence of zinc ions, too. The release of lysosomal enzymes was not influenced (lysozyme) or weakly inhibited (beta-glucuronidase). Our results may indicate an impairment of the microbicidal capacity due to the diminished phagocytosis, but a promotion of inflammatory reactions due to an increase of toxic oxygen species in the presence of zinc ions.