[In vitro assessment of candidacidal activity of human leukocyte myeloperoxidase preparation].

Myeloperoxidase (MPO), present in the azurophilic granules of human polymorphonuclear neutrophils, is important in the oxygen-dependent microbicidal activity of neutrophils. The purpose of our study was to investigate the therapeutic potency of the MPO preparations. This paper is to present our primary work on MPO isolation and its microbicidal activity assay. White blood cells, isolated freshly from normal donors, were lysed with cetyltrimehylammonium bromide to liberate myeloperoxidase. The enzyme preparation was partially purified by 50% (NH4)2SO4 precipitation followed by 65% (NH4)2SO4 precipitation. A hundred million leukocytes yielded 1.03 mg protein of the MPO preparation with the RZ of 0.31. The specific activity of the MPO preparation was about 29.25 u/mg. When 0.672 units of the MPO preparation were incubated with about 10(7) clinical isolates of Candida albicans in the presence of 0.2 mmol/L H2O2 and 0.14 mol/L NaCl. It was detected that 95.58 +/- 0.64% of the organisms were killed in the methylene blue staining system.