Activated eosinophils stimulate phosphatidylcholine secretion in primary culture of rat type II pneumocytes

Activated eosinophils in airway epithelium are involved in the pathogenesis of many airway diseases. We examined whether activated eosinophils influence the secretion of phosphatidylcholine (PC), the predominant component of pulmonary surfactant, in primary culture of rat type II pneumocytes. The eosinophils (10(5) cells/ml) activated by opsonized zymosan (100 micrograms/ml) increased PC secretion from the type II pneumocytes. The increased PC secretion reduced in the presence of both superoxide dismutase (2 units/ml) and catalase (1000 units/ml). These results suggest that activated eosinophils stimulate the secretion of pulmonary surfactant partly through superoxide anions.