Purchase this article with an account.
MA Hurt, J Niederkorn, H Alizadeh; Acanthamoeba castellanii Secretes a Novel 133 Kd Cytolytic Protein When Stimulated With Methyl -D-Manno-Pyranoside . Invest. Ophthalmol. Vis. Sci. 2002;43(13):945.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose:When the outer surface of the corneal is damaged, the epithelium has a programmed wound-healing response that includes the upregulation of mannose glycoproteins. Acanthamoebae have been shown to bind to many mannose derivatives with high affinity. Moreover, it has been shown in animal models that corneal trauma is a prerequisite for establishing Acanthamoeba keratitis. We examined the role that mannose stimulation has on the amoeba’s growth, secreted products, and ability to desquamate the corneal epithelium. Methods: Acanthamoeba castellanii were grown in PYG, PYG with methyl α-D-manno-pyranoside, or PYG with galactose. The proliferation of trophozoites and cysts was monitored for 10 days. Culture supernatants were concentrated and incubated with human and hamster corneal epithelial cells and human intestinal epithelial cells. Culture supernatant proteins were examined by FPLC size exclusion and ionic interactions. Results:Culture supernatants stimulated with methyl α-D-manno-pyranoside inhibited proliferation by 50% (P<.005), produced a 2-fold greater cyst population (P<.005), and had a 70% increase in cytolytic activity against corneal epithelial cells (P<.005). The protein was purified by FPLC and found to be highly cytolytic against corneal epithelial cells, but not human intestinal epithelial cells. Sequence analysis of digested peptides confirmed that mannose stimulated the secretion of a novel protein ∼133 Kd. Conclusion:The results suggest that after binding to mannosylated proteins on a traumatized cornea, Acanthamoeba castellanii secrete an ∼133 Kd protein that is capable of desquamating both human and hamster corneal epithelium.
This PDF is available to Subscribers Only