The use of concanavalin A to competitively inhibit Pseudomonas aeruginosa adherence to rabbit corneal epithelium

Abstract

Microbial adherence to corneal epithelial cells is the initial step in the development of infectious keratitis. In an attempt to inhibit this process, we evaluated the effects of concanavalin A (Con A) upon the adherence of Pseudomonas aeruginosa to injured rabbit corneal epithelial cells. A sterile 21-gauge needle was used to create linear epithelial injuries. Identical samples from suspensions of a pure strain of P. aeruginosa were placed on two groups of injured corneas. Prior to bacterial application, one group of corneas received topical application of Con A, a lectin that is capable of binding to alpha-D-mannose or alpha-D-glucose. The animals were sacrificed 1 hour after application of the bacteria. Scanning electron microscopy of the excised corneas revealed that, compared to the corneas that had not been exposed to Con A, those exposed to the lectin had significant fewer adherent P. aeruginosa bacilli. Additionally, only rare bacteria were noted adhering to the uninjured superficial epithelial cells. These results suggest that, by competitively binding to the exposed mannose and/or glucose groups on the surfaces of these cells, Con A is capable of inhibiting the adherence of P. aeruginosa to injured epithelial cells.