In vitro cell-to-cell interaction of Thai Acanthamoeba isolated from the environment

Abstract

Free-living amebae of the genus Acanthamoeba can be opportunistic pathogens when they have to survive in human tissues and utilize host cells as a food source. The present study was performed to investigate the potential virulence of a natural Acanthamoeba isolated from an aquatic resource in Buri Ram Province, Thailand. The ameba can grow at 37 °C and 45°C and non-pathogenic to mice by nasal instillation. The trophozoites were co-cultured with human erythrocytes and three carcinoma cells: epidermoid laryngeal carcinoma (HEp-2), cervical carcinoma (HeLa), and oral carcinoma (KB) cells. The amebae made contact first with culture cell lines within three hours and induced cytopathic changes later. They were manifested by its destruction up to a total replacement of the culture cells by amebae. The characters and dynamics of the cell changes of HEp-2, HeLa, and KB cells were similar in interaction with the amebae. No excystation or target cell destruction occurred when the Acanthamoeba cysts were inoculated. When co-incubated with erythrocytes, adherence occurred only in the presence of plasma, and most to the trophozoite stage and few attachments to the round up and cyst forms. Some small clumps of erythrocytes were found after 2 days of incubation. The present results show that cytoadherence and cytopathic effects can be produced by either Acanthamoeba pathogenic or non-pathogenic strains, which may be natural behaviors to survive or adapt to the constraints of different environments.