Chemiluminescence induced by phagocytosis of Escherichia coli by polymorphonuclear leucocytes

Chemiluminescence emitted by phagocytosing human polymorphonuclear leucocytes stimulated by Escherichia coli was measured using a liquid scintillation counter equipped with a multichannel analyser. In the presence of the amplifying agent luminol, light emission can be divided into two channels, one of which ('high energy') appears to correlate directly with phagocytic activity of the PMNL, and the other ('low energy') with the background luminol dioxygenation by the cells. Measuring in the 'high energy' window also eliminates the normal 'out of coincidence' background. The method is applicable to measuring opsonizing capacity of different sera, and responds to PMNL number, age, composition of assay medium and the integrity of the stimulating bacteria. Other bacterial strains produce a similar response, as does the artificial stimulator zymosan. Low temperature and anaerobiosis, which inhibit phagocytic killing, also suppress light emission.