Role of Pseudomonas aeruginosa culture filtrates in the association, invasion, and cytotoxicity against cloned cells from murine corneal epithelium and KB cells.

PURPOSE To clarify the effect of Pseudomonas aeruginosa culture filtrates on the association with, invasion into, and cytotoxicity against cloned cells from murine corneal epithelial cells and KB cells. METHODS Simian virus 40-transformed murine corneal epithelial (MCE) cells were established. Murine corneal epithelial cells and KB cells were infected with a protease-positive strain, IID1117 (Pa IID1117), and a protease-negative strain, IID1130 (Pa IID1130) of P. aeruginosa, and then tested for association and invasion of Pa IID1117. The cytotoxicity test was performed by incubating the cells with culture filtrate. RESULTS Association of Pa IID1117 with KB cells pretreated with Pa IID1130 was significantly promoted. After pretreatment with culture filtrate, invasion was more effective into MCE cells than into KB cells. When infecting bacteria (Pa IID1117) were pretreated with protease inhibitor, invasion of the bacteria into MCE cells and KB cells clearly decreased. The cellular damage induced by the culture filtrate of Pa IID1130 was greater than the damage by that of Pa IID1117. CONCLUSION These results suggest that association of P. aeruginosa with MCE cells and KB cells was influenced by the culture filtrates other than proteases, and that invasion of P. aeruginosa into MCE cells and KB cells was promoted by protease.