Recent research indicates that epithelial cells of the ocular surface can contribute to the allergic reaction by the release of inflammatory and/or chemotactic mediators. In this study, the role of two inflammatory mediators, previously identified in the tear film of ocular allergy subjects, TNF-α and IFN-γ, were evaluated for their effect on the release of two chemotactic mediators, IL-8 and RANTES, from cultured human conjunctival epithelial cells.
Human conjunctival epithelial cells (primary cells or HC0597 cell line) were grown to confluence and stimulated with various concentrations of TNF-α, IFN-γ, or a combination of both. Supernatants were collected at 6, 24, and 48 hours and stored frozen for subsequent ELISA analyses of RANTES and IL-8.
RANTES and IL-8 release from HC0597 cells was stimulated in a dose- and time-dependent manner following treatment with TNF-α. However, only RANTES release was modulated by IFN-γ treatment. Treatment of HC0597 cells with both TNF-α and IFN-γ resulted in a synergistic increase in the release of RANTES. This synergistic effect was confirmed using primary cultures of human conjunctival epithelial cells.
Stimulation of conjunctival epithelium with proinflammatory mediators, TNF-α and/or IFN-γ, generated the release of the chemotactic factors IL-8 and RANTES, which could act to prolong inflammation. These two chemokines may prolong inflammation by recruiting eosinophils to the ocular surface. This is the first study to compare chemokine release in a cell line and primary cells; similar chemokine release after mediator stimulation was demonstrated, indicating that the two cell types are phenotypically similar.
From the Department of Ophthalmology and Visual Sciences (E.E.S., S.K.S., L.R.G., S.D.T.), University of Texas Medical Branch, Galveston, Texas; Gillette Medical Evaluation Laboratories (S.L.W.), Gaithersburg, Maryland.
Submitted May 8, 2002.
Revision received February 18, 2003.
Accepted February 18, 2003.
Commercial relationships: none.
This study was supported by a grant from Research to Prevent Blindness, Inc.
Address correspondence and reprint requests to Stefan D. Trocme, M.D., Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, 700 University Blvd., Galveston, TX 77555-1106. E-mail: firstname.lastname@example.org