Mechanisms of non-opsonized zymosan-induced and luminol-enhanced chemiluminescence in whole blood and isolated

Summary: A lumiüol-dependent non-opsonized zymosan-induced chemiluminescence method for phagocytes in small quantities of whole blood (40; final dilution: l: 14) is described. It was characterized with reference to cellular and humoral components, and also applied to isolated neutrophils, eosinophils and monocytes. Normal values for whole blood chemiluminescence and for neutrophils, eosinophils and monocytes are presented. From the chemiluminescence characteristic of distinct phagocytes and their frequency distribution pattern in whole blood, it is concluded that whole blood chemiluminescence has its source predominantly in neutrophils. The question äs to the origin of chemiluminescence in phagocytes of whole blood and isolated neutrophils is investigated. The results support the importance of the myeloperoxidase-H2O2-halide System, but also go beyond this. The release of arachidonic acid by phospholipase A2 and of diacylglycerol and inositol trisphosphate by phospholipase C, the metabolism of arachidonic acid by the cyclooxygenase and lipoxygenase pathway, the activation of membrane NADPH oxidase by diacylglycerol and the calcium mobilisation by inositol trisphosphate are necessary for the chemiluminescence reaction. Inhibition of either mechanism suppresses the chemiluminescence response. The interaction of non-opsonized zymosan with plasma opsonins, phagocyte Fc- and complement receptors, respectively, for the initiation of chemilumines-cence, was investigated. Non-opsonized zymosan initiates a chemiluminescence response in blood phagocyte