MACROPHAGE-MEDIATED CANDIDACIDAL ACTIVITY IS AUGMENTED BY EXPOSURE TO EOSINOPHIL PEROXIDASE: A Paradigm for Eosinophil-Macrophage Interaction

Various disease states are associated with eosinophilia and the release of eosinophil peroxidase (EPO) into the microenvironment. The present study targets the effects of low levels of EPO on macrophage (MO) phagocytosis and intracellular killing of Candida albicans as well as MO oxidative activity measured as the luminescence product of luminol dioxygenation. Resident murine peritoneal MO were exposed to various concentrations of EPO. Chemiluminescence data indicate that nanomolar concentrations of EPO markedly enhanced the dioxygenation activity (respiratory burst) of MO. In other studies, the exposure of MO to 0.17 μM EPO for 10 min. enhanced MO-mediated candidacidal activity 10 fold. The above data indicate that EPO enhances certain MO functions. Also the results illustrate a previously un-recognized interaction between eosinophils and MO and implicate yet another possible role for EPO in host defenses against disease.