In vitro assessment of phagocytosis: Interspecies comparison of chemiluminescence response

Phagocytosis is a major component of the host's defences against pathogens. Particulate or soluble stimuli trigger the intracellular respiratory burst in activated phagocytes which can be measured in vitro by the luminol-enhanced chemiluminescent response. In this study, the phagocytic capacity of peripheral blood leucocytes was assayed using chemiluminescence and preliminary in vitro activation by phorbol myristate acetate, opsonized zymosan or latex beads. Leucocytes from rats, mini-pigs, dogs, monkeys and humans were preincubated for 2 hr with either doxycycline (0, 2 and 50 mug/ml) (n = 5) or lead acetate (0, 2 and 20 mug/ml) (n = 5), both compounds impairing phagocytosis. Whatever the species and the activator used, a similar dose-dependent decrease in chemiluminescence response was observed with either doxycycline or lead acetate, showing that the results can be extrapolated between species and to humans. The chemiluminescence assay is proposed as a tool for assessment of the safety of drugs and chemicals.