Chemiluminescence by polymorphonuclear leukocytes adhering to surfaces.

Stimulation of the plasma membranes of granulocytes results in an oxidative metabolic response. This response can be measured by measuring the reduction of oxidizable substrates, such as Nitro Blue Tetrazolium, as well as by measuring the energy released as light (chemiluminescence). While investigating the oxidative response of human granulocytes, we observed a marked variation in the chemiluminescence response when leukocytes were suspended in a balanced salt solution without gelatin or any other protein. We performed systematic study to investigate the role of protein in suspensions of human polymorphonuclear leukocytes. Final results were identical with human serum, albumin, fetal calf serum, and gelatin; gelatin was used as the protein source in most experiments. Polymorphonuclear leukocytes suspended in Hanks balanced salt solution without gelatin decreased in numbers during incubation at room temperature (approximately 50 percent after 60 min). Cell structures were observed on the walls of the tubes containing leukocyte suspensions without gelatin. Numbers of polymorphonuclear leukocytes were stable in suspensions containing gelatin. A chemiluminescence response which peaked at approximately 10 min and was sustained for at least 30 min was observed in suspensions of polymorphonuclear leukocytes without gelatin. This surface attachment-stimulated chemiluminescence occurred in the absence of either soluble or particulate stimuli. Chemiluminescence was inhibited by either superoxide dismutase or sodium azide and did not occur with suspensions of granulocytes from patients with chronic granulomatous disease. We postulate that both superoxide- and myeloperoxidase-dependent oxidative metabolic reactions are induced during the adherence of polymorphonuclear leukocytes to surfaces. Gelatin or other proteins in leukocyte suspending media are necessary when assays are performed to evaluate the metabolic responses of these cells to particulate or soluble stimuli.