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Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples
Published on: July 28, 2016
Non-vital polymorphonuclear leukocytes express myeloperoxidase on their surface
Jorg Flemmig1, Jacqueline Lessig, Uta Reibetanz
1Institute for Medical Physics and Biophysics, Medical Faculty, University of Leipzig, Germany.
Summary
Myeloperoxidase (MPO) appears on the surface of non-vital polymorphonuclear leukocytes (PMNs), binding to phosphatidylserine. This cell-surface MPO utilizes hydrogen peroxide, suggesting a role in PMN apoptosis.
Area of Science:
- Cell Biology
- Immunology
- Biochemistry
Background:
- Myeloperoxidase (MPO) is a heme-containing enzyme crucial in innate immunity.
- Polymorphonuclear leukocytes (PMNs) are key immune cells involved in inflammation and pathogen clearance.
Purpose of the Study:
- To investigate the cell surface expression of MPO on non-vital PMNs.
- To determine the localization and functional characteristics of surface-bound MPO.
Main Methods:
- Flow cytometry and confocal fluorescence microscopy to detect MPO antibody binding.
- Coincubation with FITC-labeled annexin V to assess phosphatidylserine localization.
- Chemiluminescence assay using Pholasin to measure MPO activity.
Main Results:
- MPO expression on the PMN cell surface increases with culture time.
- Surface MPO exhibits distinct localization patterns (patches vs. diffuse) correlating with culture duration.
- MPO colocalizes with phosphatidylserine on non-vital PMNs.
- Surface-bound MPO is enzymatically active, utilizing hydrogen peroxide.
Conclusions:
- Myeloperoxidase is expressed on the outer surface of non-vital PMNs, colocalizing with phosphatidylserine.
- This surface MPO localization and activity suggest a potential role in the process of PMN apoptosis.
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