Induction of cytokines from polymorphonuclear leukocytes and epithelial cells by ocular isolates of Serratia marcescens

Purpose: During contact lens wear, bacterial contamination of the lens can lead to the development of microbial keratitis (MK) or contact lens induced acute red eye (CLARE). Inflammatory mediators released by the host may heighten the response. We have examined the ability of human corneal epithelial cells and polymorphonuclear leukocytes (PMNs) to release cytokines upon stimulation with bacteria. Methods: Serratia marcescens strains were added to corneal epithelial cells or PMNs. After incubations Of Up to 20 hours., supernatants were assayed for the presence of inflammatory mediators by ELISA. Results: All strains stimulated PMNs to release IL-8 and LTB(4). Epithelial cells did not release LTB4. IL-8 was released after exposure to most S. marcescens isolates. A sub-group of strains stilnulated the release of TNF-alpha from corneal epithelial cells. Conclusions: S. marcescens can stimulate the release of inflammatory mediators from both PMNs and corneal epithelial cells. This release could be important in the progression and resolution of MK and CLARE.