Common methodology is inadequate for studies on the microbicidal activity of neutrophils.

Microbicidal activity of neutrophils is usually measured by colony-counting techniques after cell lysis in distilled water. While studying the effect of the reduced nicotinamide adenine dinucleotide phosphate-oxidase inhibitor diphenyleneiodonium (DPI) on the staphylocidal activity of neutrophils, we obtained inconsistent results: various degrees of inhibition in some experiments and no effect in others. The lysis step, i.

Genetic studies on myeloperoxidase deficiency in Italy.

Hereditary myeloperoxidase (MPO) deficiency is the most common neutrophil biochemical defect characterized by the lack of peroxidase activity. In order to extend the epidemiological studies on hereditary MPO deficiency in Italy, approximately 40,000 individuals were analyzed and 7 partial and 8 total MPO deficient subjects were identified. The genetic characterization of the subjects showed the presence of 3 already-known mutations (c.

Genetic characterization of myeloperoxidase deficiency in Italy.

Hereditary myeloperoxidase (MPO) deficiency (MPOD) is the most common neutrophil biochemical defect, and is characterized by a lack of peroxidase activity. In order to extend the epidemiological studies on hereditary MPOD in Italy, a population screening was carried out to detect mutations in the MPO gene. Of approximately 40,000 individuals analyzed, seven partial and eight total MPO-deficient subjects were identified.

A single-step, sensitive flow cytofluorometric assay for the simultaneous assessment of membrane-bound and ingested Candida albicans in phagocytosing neutrophils.

Background: Distinguishing ingested particles from those attached to the cell surface is an essential requirement when performing quantitative studies of phagocytosis. In the present report, we describe a simple, sensitive and reliable flow cytofluorometric method that achieves this goal in a Candida albicans-human neutrophils (PMN) system.

Methods: The assay is based on the observation that the vital dye trypan blue (TB), while quenching the green fluorescence of fluorescein-labeled C.

Evidence that elastase is the TNF-R75 shedding enzyme in resting human polymorphonuclear leukocytes.

We previously showed that a metalloprotease and a serine protease mediate shedding of the TNF-R75 (75-kDa tumor necrosis factor receptor) in neutrophils. Here we show that elastase is the TNF-R75 solubilizing serine protease. Release of the TNF-R75 by resting cells was almost totally inhibited by the serine protease inhibitor diisopropylfluorophosphate (DFP), by two synthetic, chemically unrelated, elastase-specific inhibitors and by alpha1-protease inhibitor.