Myeloperoxidase: friend and foe

  title={Myeloperoxidase: friend and foe},
  author={Seymour J. Klebanoff},
  journal={Journal of Leukocyte Biology},
  • S. Klebanoff
  • Published 1 May 2005
  • Biology
  • Journal of Leukocyte Biology
Neutrophilic polymorphonuclear leukocytes (neutrophils) are highly specialized for their primary function, the phagocytosis and destruction of microorganisms. When coated with opsonins (generally complement and/or antibody), microorganisms bind to specific receptors on the surface of the phagocyte and invagination of the cell membrane occurs with the incorporation of the microorganism into an intracellular phagosome. There follows a burst of oxygen consumption, and much, if not all, of the… 

Myeloperoxidase in human neutrophil host defence

The most rapid and complete antimicrobial action by human neutrophils against many organisms relies on the combined efforts of the azurophilic granule protein myeloperoxidase and hydrogen peroxide from the NADPH oxidase to oxidize chloride, thereby generating hypochlorous acid and a host of downstream reaction products.

Neutrophil Myeloperoxidase: Soldier and Statesman

This review examines more recent information on the interaction between MPO, its bioreactive reaction products, and targets within the inflammatory microenvironment and suggests that the pro-inflammatory pathological role of MPO may be a particular feature of chronic inflammation.

Redox reactions and microbial killing in the neutrophil phagosome.

This review focuses on what oxidants are produced and how they kill in the phagosome, and how neutrophils kill microorganisms by an MPO-dependent mechanism that is almost certainly due to HOCl.

Human myeloperoxidase in innate and acquired immunity.

The phagocytes: neutrophils and monocytes.

Over the last 50 years, many genetic and molecular disorders of phagocytes have been identified, leading to improved diagnosis and treatment of conditions which predispose patients to the risk of recurrent fevers and infectious diseases.

The Dual Role of Myeloperoxidase in Immune Response

  • J. Arnhold
  • Biology
    International journal of molecular sciences
  • 2020
This review critically reflects on the beneficial and harmful functions of MPO against the background of immune response.

Measurement of respiratory burst products generated by professional phagocytes.

Three of these techniques, chemiluminescence amplified by luminol/ isoluminol, the absorbance change following reduction of cytochrome c, and the fluorescence increase upon oxidation of p-hydroxyphenylacetate, are described in detail in this chapter.

Measurement of respiratory burst products, released or retained, during activation of professional phagocytes.

Basic techniques to measure/quantify ROS generation by phagocytes during activation of the respiratory burst are described in detail with special emphasis on how to distinguish between ROS that are released extracellularly, and those that are retained within intracellular organelles.

Neutrophils in the innate immune response.

The role of human neutrophils in the innate host response to infection is provided and some of the recent advances in neutrophil biology are summarized.

Measurement of Respiratory Burst Products, Released or Retained, During Activation of Professional Phagocytes.

Methods used to measure and quantify ROS generation by phagocytes can be valuable tools in research spanning from basic phagocyte biology to diagnosis of diseases linked to the NADPH-oxidase and more clinically oriented research on innate immune mechanisms and inflammation.



Cytochemical demonstration of hydrogen peroxide in polymorphonuclear leukocyte phagosomes

In the present investigation, the diaminobenzidine reaction of Graham and Karnovsky (5), modified to utilize endogenous myeloperoxidase and hydrogen peroxide, has been applied to actively phagocytizing PMN to demonstrate cytochemically the presence of H2O2 in thephagocytic vacuole.

Novel cytochrome b system in phagocytic vacuoles of human granulocytes

A cytochrome b system which becomes incorporated into the phagocytic vacuoles of human neutrophils, and abnormalities in patients with CGD implicate it as an essential component of the microbicidal oxidase system.

The bactericidal effects of the respiratory burst and the myeloperoxidase system isolated in neutrophil cytoplasts.

The respiratory burst of phagocytic cells is associated with a rise in vacuolar pH

A major consequence of the defective function of this oxidase in neutrophils and monocytes from CGD patients is an absence of the normal initial rise, and an unusually rapid and extensive fall in pH which is itself associated with the impairment of the killing and digestion of intracellular staphylococci.

Human Neutrophils Use the Myeloperoxidase-Hydrogen Peroxide-Chloride System to Chlorinate but Not Nitrate Bacterial Proteins during Phagocytosis*

Observations support the view that the phagolysosome of human neutrophils uses the myeloperoxidase-hydrogen peroxide-chloride system to chlorinate bacterial proteins.

Human neutrophils employ chlorine gas as an oxidant during phagocytosis.

Gas chromatography-mass spectrometric analysis of head space gas revealed that the complete myeloperoxidase-hydrogen peroxide-chloride system generated Cl2 and that human neutrophils use an oxidant with characteristics identical to those of Cl2 during phagocytosis, indicating that a Cl2-like oxidant is generated in the phagolysosome.

Role for endogenous and acquired peroxidase in the toxoplasmacidal activity of murine and human mononuclear phagocytes.

Oxygen products generated by the respiratory burst of mononuclear phagocytes are microbicidal to intracellular pathogens including Toxoplasma gondii. The toxicity of one of these products, H(2)O(2),

Myeloperoxidase modulates the phagocytic activity of polymorphonuclear neutrophil leukocytes. Studies with cells from a myeloperoxidase-deficient patient.

The oxidizing activity of the MPO-H2O2-halide system may modulate the inflammatory response by impairing certain receptor-mediated recognition mechanisms of phagocytic cells, which otherwise could elicit inflammatory reactions and tissue injury.

Role of myeloperoxidase in respiratory burst of human polymorphonuclear leukocytes

It is suggested that normal PMNs and MPO-deficient PMNs do not intrinsically differ in O2− generating potential and that the difference in the respiratory burst observed during phagocytosis may be accounted for by a more marked deterioration, innormal PMNs, of one or more functions related to the respiratory Burst.

Clinical manifestation of myeloperoxidase deficiency

  • F. Lanza
  • Biology, Medicine
    Journal of Molecular Medicine
  • 1998
Evidence from a number of investigators indicates that individuals with total MPO deficiency show a high incidence of malignant tumors, and it can be speculated that the neutrophil MPO system plays a central role in the tumor surveillance of the host.