Myeloperoxidase binds to and kills Entamoeba histolytica trophozoites

Abstract

During amebic invasion, neutrophils are a key component in either protecting against invading trophozoites or contributing to tissue damage. Upon degranulating or being lysed, neutrophils release toxic substances that can kill amebas as well as damage host tissue. In a previous study we identified a protein from nonspecifically stimulated peritoneal exudates of hamster that has peroxidase and marked amebicidal activity. In the current study we analyzed the in vitro amebicidal effect of purified hamster myeloperoxidase (MPO). The results demonstrate that MPO must bind directly to the surface of Entamoeba histolytica trophozoites in order to carry out amebicidal activity by using the H(2) O(2) produced by the amebas themselves. Myeloperoxidase-incubated amebas showed important morphological and ultrastructural alterations that increased with incubation time. Changes included an increase of vacuoles in the cytoplasm, a decrease of glycogen, alterations of nuclear morphology and disturbances in the plasma membrane culminating in complete ameba destruction.

Equine myeloperoxidase: A novel biomarker in synovial fluid for the diagnosis of infection

“…In general, these bands were located between 75 and 100 kDa, above 50 kDa and around 37 kDa. The 50 and 37 kDa protein sizes are consistent with earlier electrophoresis data on purified equine MPO and with immunoblotting data on lysates of human MPO‐containing tissues . Especiallly in nonreducing conditions, MPO can occur as a tetrameric enzyme (∼150 kDa) with 2 β‐ (or light) and 2 α‐ (or heavy) subunits .…”

Neutrophils extracellular traps damage Naegleria fowleri trophozoites opsonized with human IgG

“…It was shown previously for human neutrophils that a partial disorder of MPO production resulted in a reduced ability to produce NETs, while a total absence of MPO inhibits NET formation . Thus, MPO may likely bind directly to the surface of N. fowleri trophozoites to carry out amoebicidal activity using H 2 O 2 produced by the amoebas themselves as was reported for Entamoeba histolytica . Ferrante et al .…”

The MPO system participates actively in the formation of an oxidative environment produced by neutrophils and activates the antioxidant mechanism of Naegleria fowleri

“…The result also suggests that MPO can bind to the N. fowleri surface, similar to that observed with Entamoeba histolytica trophozoites. 46 On the other hand, we observed that N.…”