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Updated: Sep 13, 2025
Author Spotlight: Studying Behavior of Acanthamoeba to Develop Targeted Strategies for Preventing Acanthamoeba Keratitis
Published on: September 20, 2024
Interaction of Acanthamoeba T5 with a Vero Cell Culture: An Exploratory Study Using Live-Cell Imaging and Confocal
Elizabeth Abrahams-Sandi1,2, Mónica Prado-Porras1,2, Johan Alvarado-Ocampo1,2
1Departamento de Parasitología, Facultad de Microbiología, Universidad de Costa Rica, Saint Jose 11501, Costa Rica.
Abstract:
Acanthamoeba is a free-living amoeba widely distributed in nature, responsible for clinical cases of encephalitis and keratitis in humans. Due to the increase in the number of cases in recent years, understanding the damage mechanisms employed by the amoeba is very important for the clinical management of the disease, development of diagnostic tools and identification of therapeutic targets. To date, most experimental studies to determine the virulence factors and pathogenesis of Acanthamoeba have employed genotype T4 as an infection model, resulting in minimal information regarding other genotypes. In this work, we explored the direct and indirect effect of A. lenticulata genotype T5 trophozoites and their excretion/secretion products over a Vero cell monolayer. Using confocal and real-time microscopy, we witnessed a significant direct mechanical action of the trophozoites on the cells during the adhesion stage. Additionally, we observed the formation of digitiform phagocytic structures through which the nuclear material of the target cell appears to be specifically sucked by the amoeba without the involvement of any lytic mechanism. Moreover, an increase in lysosomal activity in the cytoplasm of trophozoites of Acanthamoeba, and the effect of the excretion/secretion products on the actin filaments of the target cells were observed during the first 2-3 h post-infection.
Insights
Acanthamoeba genotype T5 directly damages host cells by mechanical suction, not lysis. Its excretions also disrupt host cell actin, offering new insights into amoebic keratitis and encephalitis pathogenesis.
Area of Science:
- Microbiology
- Cell Biology
- Parasitology
Background:
- Acanthamoeba infections, including encephalitis and keratitis, are increasing.
- Genotype T4 is the common model, but other genotypes' virulence is understudied.
- Understanding Acanthamoeba damage mechanisms is crucial for clinical management.
Purpose of the Study:
- To investigate the pathogenic mechanisms of Acanthamoeba lenticulata genotype T5.
- To analyze the direct and indirect effects of T5 trophozoites and their products on host cells.
- To elucidate the interaction between Acanthamoeba T5 and Vero cells.
Main Methods:
- Confocal and real-time microscopy were used to observe trophozoite-cell interactions.
- Vero cell monolayers were exposed to Acanthamoeba T5 trophozoites and their excretion/secretion products.
- Cellular responses, including mechanical action, phagocytosis, and actin filament changes, were analyzed.
Main Results:
- Acanthamoeba T5 trophozoites exhibited direct mechanical action and formed digitiform structures for nuclear material suction.
- Amoebic phagocytosis involved specific sucking of nuclear material without lysis.
- Excretion/secretion products affected host cell actin filaments within 2-3 hours post-infection.
- Increased lysosomal activity was observed in Acanthamoeba trophozoites.
Conclusions:
- Acanthamoeba T5 employs direct mechanical force and specific nuclear suction for cell damage.
- Excretion/secretion products contribute to pathogenesis by disrupting host cell cytoskeleton.
- Findings provide insights into Acanthamoeba virulence beyond genotype T4, aiding therapeutic target identification.
