Pretreatment With TLR2 and TLR4 Ligand Modulates Innate Immunity in Corneal Fibroblasts Challenged WithAspergillus fumigatus

PURPOSE: To study the innate immunity in telomerase-immortalized human stroma fibroblasts (THSFs) challenged with Aspergillus fumigatus hyphae after copretreatment with TLR2 and TLR4 ligand. METHODS: THSFs were pretreated with different concentrations of zymosan and/or lipopolysaccharide (LPS) at different time periods, and challenged with high-dose Aspergillus fumigatus hyphae. The gene expression and protein secretion of inflammatory cytokines (TNF-α, IL-6, and IL-8) were detected by RT-PCR and ELISA. The effects of stimulation or pretreatment of TLR ligands on proliferation of THSFs were measured by MTT analysis. RESULTS: In the certain concentration range, pretreatment of THSFs with zymosan suppressed gene expression of inflammatory cytokines (TNF-α and IL-6). Copretreatment with zymosan and LPS suppressed gene expression and protein secretion more strongly compared with pretreatment with zymosan or LPS alone. Zymosan and/or LPS pretreatment suppressed lethal effect of A. fumigatus to THSFs in a certain period. CONCLUSIONS: Pretreatment of THSFs with TLR2-specific ligand zymosan results in a state of A. fumigatus hyphae tolerance. Copretreatment with TLR2 and -4 ligands (zymosan and LPS) leads to a stronger state of A. fumigatus hyphae tolerance, and suppresses the lethal effect of A. fumigatus.