Adhesion of Acanthamoeba on Cosmetic Contact Lenses

BACKGROUND: This study aimed to evaluate the adhesion of Acanthamoeba trophozoites on cosmetic contact lenses (CLs) with and without CL care multipurpose solution (MPS) treatment. METHODS: Acanthamoeba lugdunensis L3a trophozoites were inoculated onto disks trimmed from CLs: 1-day Acuvue moist, 1-day Acuvue define, Acuvue 2, and Acuvue 2 define. After 18-hour inoculation, the number of adherent trophozoites was counted under phase contrast microscopy. The effects of MPS, Opti-Free Express, soaking CLs for 6 hours, on Acanthamoeba adhesion were analyzed. Scanning electron microscopic examination was performed for assessment of Acanthamoeba attached on the lens surface. RESULTS: Acanthamoeba trophozoites showed greater adhesion to cosmetic CL (P = 0.017 for 1-day CL and P = 0.009 for 2-week CL) although there was no significant difference between the types of cosmetic CL. On all lenses, the number of adherent Acanthamoeba was significantly reduced after treatment with MPS (P < 0.001 for 1-day Acuvue moist, P = 0.046 for 1-day Acuvue define, P < 0.001 for Acuvue 2, and P = 0.015 for Acuvue 2 define), but there was still significant difference between conventional and cosmetic CLs (P = 0.003 for 1-day CL and P < 0.001 for 2-week CL, respectively). More attachment of Acanthamoeba was observed on colored area and the acanthopodia of Acanthamoeba was placed on the rough surface of colored area. CONCLUSION: Acanthamoeba showed a greater affinity for cosmetic CL and mostly attached on colored area. Although MPS that contained myristamidopropyl dimethylamine reduced the adhesion rate, there was a significant difference between conventional and cosmetic CLs.

Purification and characterization of a 33 kDa serine protease from Acanthamoeba lugdunensis KA/E2 isolated from a Korean keratitis patient

In order to evaluate the possible roles of secretory proteases in the pathogenesis of amoebic keratitis, we purified and characterized a serine protease secreted by Acanthamoeba lugdunensis KA/E2, isolated from a Korean keratitis patient. The ammonium sulfate-precipitated culture supernatant of the isolate was purified by sequential chromatography on CM-Sepharose, Sephacryl S-200, and mono Q-anion exchange column. The purified 33 kDa protease had a pH optimum of 8.5 and a temperature optimum of 55 degrees C. Phenylmethylsulfonylfluoride and 4- (2- Aminoethyl) -benzenesulfonyl-fluoride, both serine protease specific inhibitors, inhibited almost completely the activity of the 33 kDa protease whereas other classes of inhibitors did not affect its activity. The 33 kDa enzyme degraded various extracellular matrix proteins and serum proteins. Our results strongly suggest that the 33 kDa serine protease secreted from this keratopathogenic Acanthamoeba play important roles in the pathogenesis of amoebic keratitis, such as in corneal tissue invasion, immune evasion and nutrient uptake.

Penetration of Acanthamoeba Lugdunensis into the Corneal Epithelium in Organ Cultured Human Cornea: A Scanning and Transmission Electron Microscopy Study

The purpose of this study was to investigate the process of Acanthamoeba penetration into the organ-cultured human cornea by scanning and transmission electron microscopy. Human cornea was obtained through the eye bank of Catholic Medical Center and cultured in Optisol solution at at37degrees C. Acanthamoeba lugdunensis was cultured on non-nutrient agar plate and collected to make suspension in concentration of 1 x 106/ml.100 microliterof amoeba suspension was added to the epithelial surface of cultured cornea and each cornea was incubated for 48 and 120 hours. Each cornea was examined by scanning and transmission electron microscopy at each time point. In scanning electron microscopy, Acanthamoeba penetrated into the deep epithelial layer through the intercellular space with progressive epithelial breakdown. In transmission electron microscopically, Acanthamoebapene-trated through the intercellular space of the superficial corneal epithelium and reached to the basement membrane of basal corneal epithelium. Penetrating trophozoites had numerous electronense, mineral-like deposits in their cytoplasm and secreted enzyme-like materials. In conclusion, Acanthamoebae penetrated through the intercellular space of the corneal epithelium by their locomotion and migrated into the deep epithelial layer with secreation of enzyme-like materials and phagocytosis until they reached to the basement membrane of the basal corneal epithelium.

Adherence of Acanthamoeba Lugdunensis on the Corneal Epithelium in Organ Cultured Human Cornea: A Scanning and Transmission Electron Microscopy Study

The purpose of this study was to investigate the ability of Acanthamoeba to adhere to the epithelial cells of human cornea. Human corneas, obtained through the eye bank of Catholic Medical Center, were cultured in Optisol solution at 37degreesC. Trophozoites of Acanthamoeba lugdunensis cultured on non-nutrient agar plate were collected to make a suspension in concentration of 1x106/ml. 100microliter of amoeba suspension was added to the epithelial surface of cultured human corneas and each cornea was incubated for 12 hours. Each cornea was examined with scanning and transmission electron microscope. On scanning electron microscopy, trophozoites adhered to each other and to the corneal epithelium, especially to intercellular junction by their extended lobopodia at 12 hour-incubation. On transmission electron microscopy, trophozoites showed limited regions of attachment to the corneal epithelium at 12 hour-incubation, and the attached areas showed desmosome-like structure. Trophozoites adhered to each other by cytoplasmic interdigitation. In conclusion, trophozoites adhere to the corneal epithelial surface by their cytoplasmic processes and their processes appeared to have affinity to intercellular junctions of the corneal epithelium. Attachment regions between corneal epithelium and amoeba were characterized as desmosomelike junctions.