Systemic overexpression of IFN-gamma and IL-5 exacerbates early phase reaction and conjunctival eosinophilia, respectively, in experimental allergic conjunctivitis.

Abstract

AIMS/BACKGROUND: To investigate how systemic overexpression of IL-4, IL-5 and IFN-gamma affects the severity of experimental conjunctivitis (EC) in mice. METHODS: The tibialis anterior muscle of naive BALB/c mice was electroporated with IL-4, IL-5, IFN-gamma or a control gene, and then the mice blood and conjunctivas were harvested to measure the eosinophil content in these tissues. To evaluate the effects of cytokine gene electroporation on the early-phase reaction (EPR), cytokine gene-electroporated ragweed (RW)-immunised mice were intravenously injected with Evans Blue (EB) and then challenged with RW in eye-drops. Thirty minutes later, their conjunctivas were harvested to extract EB and evaluate the EPR. Additionally, 24 h after RW challenge, conjunctivas were harvested from cytokine gene-electroporated RW-immunised mice, which had not received intravenous injection of EB, to measure conjunctival eosinophilia. RESULTS: Significantly more eosinophils were detected in the blood and conjunctivas of IL-5-electroporated mice in which EC was not induced. The intensity of the EPR was significantly greater in IFN-gamma-electroporated mice. Significantly greater eosinophil infiltration was seen in the conjunctivas of IL-5-electroporated EC-developing mice. CONCLUSIONS: It appears that systemic IL-5 and IFN-gamma play different roles in the development of EC.