Luminol-dependent chemiluminescence analysis of the variables of the phagocytic response by canine granulocytes

Variables which influence the oxygen-dependent chemiluminescence (CL) response of canine polymorphonuclear leukocytes (PMN) to zymosan were examined in a luminol-dependent CL assay system. Maximal CL responses were obtained when 5 x 10(6) canine PMN, isolated from heparinized blood, were assayed at 37 degrees C in a Luminometer. The response was enhanced by the addition of 0.05 mM Luminol and inhibited by the addition of 0.06 mM sodium azide and 60 micrograms superoxide dismutase. Repeatability on a given day was very good; however, day to day variations in CL activity prevented direct comparison of phagocytic activity between days. Opsonization of zymosan in equine serum significantly reduced the CL response by canine PMN as compared to opsonization of zymosan in autologous or homologous canine serum and bovine serum. The present results show that luminol-dependent CL analysis can be used to measure phagocytosis by canine granulocytes in a luminometer and has potential use in clinical situations.