Growth of acanthamoeba on human corneal epithelial cells and keratocytes in vitro.

Acanthamoebic keratitis, a potentially devastating infection usually associated with contact lens wear, has been recognized with increasing frequency in recent years. Once the Acanthamoeba organisms gain access to the human cornea, it is not clear which constituents of the corneal milieu provide a substrate for their growth. The growth of Acanthamoeba polyphaga was investigated on cultured monolayers of human corneal epithelial cells, stromal keratocytes, and stromal homogenate suspensions. Growth was determined through organism counts and observation of cytopathic effects on tissue culture dishes. Compared with tissue culture media controls, acanthamoebic growth was supported by cultured epithelial cells and keratocytes but not stromal homogenates. These results suggest that in acanthamoebic keratitis the organisms depend on the cellular components of the cornea as substrates for growth. This in vitro model may also provide further information on the pathogenesis of keratitis and a system for drug sensitivity testing.