A Sequential Model of Host Cell Killing and Phagocytosis by Entamoeba histolytica

Abstract

The protozoan parasite Entamoeba histolytica is responsible for invasive intestinal and extraintestinal amebiasis. The virulence of Entamoeba histolytica is strongly correlated with the parasite's capacity to effectively kill and phagocytose host cells. The process by which host cells are killed and phagocytosed follows a sequential model of adherence, cell killing, initiation of phagocytosis, and engulfment. This paper presents recent advances in the cytolytic and phagocytic processes of Entamoeba histolytica in context of the sequential model.

Figure 1

Sequential model of cell killing and phagocytosis by Entamoeba histolytica. Adherence, cell killing, and initiation of phagocytosis leading to engulfment of host cells are depicted from left to right. Abbreviations: cysteine protease adhesin (CPADH), transmembrane kinase (TMK), serine-threonine-isoleucine rich protein (STIRP), reactive oxygen species (ROS), serine-rich Entamoeba histolytica protein (SREHP), cysteine protease 5 (CP5), and phosphatidylserine (PS).

Figure 2

Venn diagram summarizing results of Entamoeba histolytica BLAST searches using the extracellular domains of CED-1 (C. elegans), eater (D. melanogaster), and STAB2 (H. sapiens). Fifty-five members of the E. histolytica transmembrane kinase gene family share significant homology to these representative scavenger receptors.