Interaction Of Mannose - Binding Lectin With Dectin - 1 And TLR2 In Fungal Keratitis

Objective:To investigate the role of Mannose binding lectin(MBL) in innate immunity and the interaction between MBL and Dectin-1, TLR2 in in the cultured tolerated human cornea epithelial cells(HCECs) stimulated with the Aspergillus fumigatus(A. fumigatus).Methods: Real-time PCR and Wesstern blot were used to dectect the expression of MBL in the normal and infected HCECs which were challenged with A. fumigatus hypha. A. fumigatus hypha was pre-treated with recombination human MBL(rh MBL) protein or anti-MBL for 30 min before challenging HCECs. Real-time PCR, Wesstern blot and enzyme-linked immunosorbent assay(Elisa) were used to exam the expression of Dectin-1, TLR2, IL-1β and TNF-α. When treated with laminarin and anti-TLR2, the MBL expression was assessed at both m RNA and protein levels.Results: MBL was expressed in HCECs. The MBL expression increased when stimulated with A. fumigatus hypha in time-dependent manner. Rh MBL can promote the IF-1β, TNF-α expressions at both m RNA and protein levels in a dose-dependent manner, while pretreated with MBL monoclonal antibody, the expressions all decreased. Rh MBL enhanced the expressions of Dectin-1 and TLR2 in a dose-dependent manner, and MBL monoclonal suppressed the production of Dectin-1 and TLR2. Pretreated with laminarin and TLR2 neutralizing antibody, the expression of MBL and IL-1β and TNF-α decreased at the peak point.Conclusion: These data demonstrate that the HCECs can produce MBL,and the production of MBL can be increased by stimulation of A. fumigatus hypha. MBL plays an important role in the early phase of recognizing A. fumigatus hypha antigen and induces the expressions of cytokines. MBL promotes the expressions of Dectin-1 and TLR2 to enhance the innate immune response indirectly. MBL interacts with Dectin-1 and TLR2 to contribute to the innate immune response of fungal keratitis.