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

Abstract

To study the innate immunity in telomerase-immortalized human stroma fibroblasts (THSFs) challenged with Aspergillus fumigatus hyphae after copretreatment with TLR2 and TLR4 ligand. 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. 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. 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.