Erythrophagocytosis inEntamoeba histolyticaandEntamoeba dispar: A Comparative Study

Abstract

Entamoeba histolyticais the causative agent of human intestinal and liver amebiasis. The extraordinary phagocytic activity ofE. histolyticatrophozoites has been accepted as one of the virulence mechanisms responsible for their invasive capacity. The recognition of the noninvasiveEntamoeba disparas a different species has raised the question as to whether the lack of pathogenic potential of this ameba correlates with a limited phagocytic capacity. We have therefore compared the process of erythrophagocytosis in both species by means of light and video microscopy, hemoglobin measurement, and the estimation of reactive oxygen species (ROS). In the present study, we confirmed thatE. disparhas lower erythrophagocytic capacity. We also observed by video microscopy a new event of erythrocyte opsonization-like in both species, being more characteristic inE. histolytica. Moreover,E. disparshowed a lower capacity to produce ROS compared with the invasive species and also showed a large population of amoebae that did not engulf any erythrocyte over time. Our results demonstrate thatE. histolyticahas a higher phagocytic capacity thanE. dispar, including a higher rate of production of ROS in the course of ingesting red blood cells.