Figure 1.

The lifecycle of Entamoeba histolytica is influenced by the microbiota. (Two cellular forms make up the lifecycle of Entamoeba, the contaminating cyst and the trophozoite. Infection occurs directly upon ingestion of the cyst by a new host, without intermediate hosts as a vector. The trophozoite colonizes the large intestine as a commensal-like, where it feeds on bacteria and divides. Trophozoite populations can reach high densities and aggregates due to amoebic surface molecules recognizing galactose ligands (e.g. lectins) that interact with mucus. High trophozoite density is a key parameter of encystation, and aggregation should trigger the transition from exponential growth to encystation following the formation of multicellular giant cells (MGC) where the cyst forms. The MGC phenotype depends on the transcription factor ERM-BP which has no role in the aggregation process.