Abstract
Abstract: :
Purpose: Herpes simplex virus–1 (HSV–1)–induced stromal keratitis (HSK) is an immune mediated disease of the cornea orchestrated by CD4+ Th1 lymphocytes. IFN–γ is known to participate in the development of HSK. In this study we examined the efficacy of antisense oligonucleotides targeting IFN–γ mRNA (IFN–γ–AS) in vitro to decrease the secretion of IFN–γ and to modulate the development of experimental HSK after topical treatment. Methods: BALB/c mice were injected subepithelially with IFN–γ–AS, irrelevant control oligonucleotides (IFN–γ–CON) or buffer on days –1, 1 and 4. Another group of mice was left untreated. Corneal infection of all animals was performed with 105 PFU HSV–1 on day 0. The mice were examined for signs of corneal disease. Eyes for histology were collected 14 and 28 days after infection. Splenic cells obtained from infected animals were co–cultured with various concentrations of IFN–γ–AS and IFN–γ–CON. The cells were activated antigen–specifically or with ConA. Supernatants were harvested after 24 hours and were assayed for the amount of IFN–γ by ELISA. Results: A concentration dependent downregulation of IFN–γ in the splenic cell culture supernatants was achieved in the coculture experiments with IFN–γ–AS when compared to IFN–γ–CON. In vivo, course and severity of epithelial keratitis did not differ between the groups of mice. In contrast, marked differences were observed concerning stromal keratitis. On day 28 post infection the average HSK score in IFN–γ–AS treated mice was 0.375. In contrast the HSK in the other three groups of mice scored 2 (buffer treatment), 2.5 (IFN–γ–CON treatment), and 3.5 (only infected mice). Even 8 weeks post infection IFN–γ–AS treated mice developed only minor or no signs of HSK. Histological findings and the counts of inflammatory cells in the cornea confirmed the clinical differences. Conclusions: IFN–γ–AS were useful to suppress the IFN–γ production of lymphocytes in vitro. In vivo the ASON targeting IFN–γ–mRNA were effective to protect mice from corneal lesions.
Keywords: cytokines/chemokines • herpes simplex virus • immunomodulation/immunoregulation