Interleukin-4 is not critical to pathogenesis in a mouse model of Pseudomonas aeruginosa corneal infection.

PURPOSE: To determine the contribution of interleukin-4 (IL-4) to the initial host response during corneal infection with Pseudomonas aeruginosa in a mouse model. METHODS: Corneas of 6- to 8-week-old IL-4(-/-) and wild-type mice were topically challenged with P. aeruginosa. Ocular tissue was collected 24 hr and 7 days postchallenge. Viable bacterial counts, myeloperoxidase assays, cytokine levels, and clinical and histological examinations were performed. RESULTS: During challenge with P. aeruginosa, no differences were observed clinically, histologically, or in bacterial load between IL-4(-/-) and wild-type mice at either time point. However, differences in cytokine levels of IL-6, KC, and IL-10 were observed. CONCLUSIONS: The data presented indicate that IL-4, a central Th2 cytokine, may not be critical to the pathogenesis or bacterial clearance in this model of P. aeruginosa bacterial keratitis during the early stages of the infectious process.