MyD88 regulation of Fusarium keratitis is dependent on TLR4 and IL-1R1 but not TLR2

AB Tarabishy, B Aldabagh, Y Sun… - The Journal of …, 2008 - journals.aai.org
AB Tarabishy, B Aldabagh, Y Sun, Y Imamura, PK Mukherjee, JH Lass, MA Ghannoum
The Journal of Immunology, 2008journals.aai.org
The fungal pathogens Fusarium solani and Fusarium oxysporum cause severe corneal
disease in the United States and worldwide and were the causative organisms in a recent
outbreak of contact lens-associated keratitis. To characterize innate immunity in Fusarium
keratitis, we developed a murine model in which conidia are injected into the corneal
stroma. Immunocompetent C57BL/6 mice rapidly developed severe corneal opacification
associated with neutrophil infiltration and clearance of Fusarium hyphae. In contrast …
Abstract
The fungal pathogens Fusarium solani and Fusarium oxysporum cause severe corneal disease in the United States and worldwide and were the causative organisms in a recent outbreak of contact lens-associated keratitis. To characterize innate immunity in Fusarium keratitis, we developed a murine model in which conidia are injected into the corneal stroma. Immunocompetent C57BL/6 mice rapidly developed severe corneal opacification associated with neutrophil infiltration and clearance of Fusarium hyphae. In contrast, neutrophil infiltration was delayed in MyD88−/− mice, resulting in uncontrolled growth of Fusarium hyphae in the corneal stroma and anterior chamber, and eventually resulting in corneal perforation. Corneal opacification scores in TLR2−/−, TLR4−/−, and TLR2/4−/− mice were similar to those of C57BL/6 mice; however, TLR4−/− and TLR2/4−/− mice had impaired antifungal responses. The phenotype of infected IL-1R1−/− mice was similar to that of MyD88−/− mice, with uncontrolled fungal growth resulting in corneal perforation. IL-1R1−/− mice also produced significantly less CXCL1/KC in the corneal stroma compared with C57BL/6 mice consistent with delayed neutrophil recruitment to the corneal stroma. Together, these findings indicate that IL-1R1 and MyD88 regulate CXC chemokine production and neutrophil recruitment to the cornea, and that TLR4 has an important role in controlling growth and replication of these pathogenic fungi.
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