Oxidative requirement for degranulation of human peripheral blood eosinophils

Eosinophils possess both oxygen-dependent and oxygen-independent mechanisms for damaging helminthic parasites such as schistosomula. We have studied the release of the granular enzymes β-glucuronidase and arylsulfatase to evaluate the oxidative requirement for degranulation. Both ionophore-mediated and immunoglobulin G-mediated release of granular enzymes were enhanced in the presence of oxygen (P ≤ 0.05). Calcium ionophore-mediated degranulation under aerobic conditions was reduced by the addition of the degradative enzymes catalase and superoxide dismutase, suggesting that active oxygen products enhance degranulation. In contrast, oxygen products did not appear to contribute to degranulation induced by immunoglobulin G-coated beads.