Ex Vivo Goat Corneal Model for Investigating Host Immune Responses and Antifungal Drug Testing in <i>Fusarium</i> Keratitis

Fusarium Keratitis is a corneal infection that causes blindness if left untreated. Immune profiling of Fusarium-infected corneas may facilitate the development of an effective immunotherapy. The ex vivo caprine (goat) cornea model examines immune cell and cytokine activity in response to Fusarium keratitis. Dissected caprine corneas maintained in ex vivo culture conditions were infected with the clinical Fusarium isolate (CSH_1) to study local immune responses. Immuno-phenotyping was performed using immune cell markers CD45, CD11b, and HLA-DR/DQ, followed by quantification of IL-1ß, IL-6, IFN-γ, TGF-ß, IL-4, IL-10, and MCP-1 through ELISA. The efficacy of antifungals was evaluated by sectioning drug-treated infected corneas by H&E staining and cytokine profiling to assess the immunomodulatory effect of antifungal treatment. Results show that CD45⁺ lymphocytes, recognized as a universal marker for immune cells, were abundant in the cornea. Activated myeloid cells (CD 11b⁺HLA DR/DQ⁺) and cytokines IL-1ß, IL-6, IFN-γ, TGF-ß, IL-4, IL-10, and MCP-1 were significantly elevated in infected corneas relative to uninfected samples. Among the drugs tested, posaconazole showed complete inhibition of Fusarium, while natamycin and amphotericin B showed the least inhibition and moderate inhibition was shown by voriconazole. The ex vivo model offers a valuable framework for evaluating pre-clinical efficacy of different treatment protocols for fungal keratitis on local tissue.