Figure 3.

Acanthamoeba-induced cytopathic effect. Acanthamoebae (2 × 10⁵ parasites/ml) were added to confluent cultures of corneal epithelium in 24-well plates, and the cultures were incubated in a CO₂ incubator for varying periods. At the end of the incubation period, the plates were stained with Giemsa and photographed. Top panel shows the photographs of the wells and lower panel shows the light micrographs of representative areas. Approximate cell density in each well, as measured by scanning the plates in a computer-assisted Bio-Image scanner, is shown in the top right panel. A value of 1.0 was assigned to the cell density of the plates incubated in media alone (Cont.). The values for cultures incubated with amoebae are expressed as change in the density with respect to control plates. Note that during the early phase (8 h), small cell-free plaques appeared in the monolayer; with continued incubation, the size of cell-free areas increased (16 h), and eventually monolayer surrounding the large plaques lifted entirely from the culture dish, resulting in almost complete loss of the cell layer. (Reprinted with permission from Cao Z ET al.³³)