Introduction & Objective: Acanthamoeba is free-living amoeba that is found in soil, water, air as well as in human pharynx. Acanthamoeba is causative agent of granulomatose amoebic encephalitis (GAE) in immunosuppressed and AIDS individuals and amoebic keratitis in people who use the lens. Pathogenic species of Acanthamoeba have protein receptors named mannose binding protein (MBP). Acanthamoeba via MBP adhere to the glycoproteins included mannose. Acanthamoeba adhesion to the target cells induces a protease secretion is called mannose inducing protein-133 (MIP-133). Exogense mannose can inhibit the adherence of Acanthamoeba also, it can increase the cytopathatic effect (CPE) through increase the secretion of MIP-133. In the present work, the effect of monosaccharides on the virulance of Acanthamoeba isolated from patient with amoebic keratitis, in HeLa cell culture was investigated.

Materials & Methods: The isolates were cultured in HeLa cell culture, then 100, 50, 10, 1 and 0.1 mM of galactose, glucose and mannose were added to plates. Plates were observed with invert microscope in 8, 16, 32, 48, and 72 hours after culture.

Results: Data implicated that mannose (100 mM ) showed the highest effect on increasing cytopathy of Acanthamoeba in HeLa cell culture. Meanwhile, galactose (100 mM) increased the virulence of Acanthamoeba in the cell culture after 32 hours.

Conclusion: Adding mannose and galactose to HeLa cell culture contain Acanthamoeba can increase the virulence of the parasite significantly.