Lentivirus-mediated PD-L1 overexpression in bone marrow-derived dendritic cells induces immune tolerance in a rat keratoplasty model

摘要

Purpose: The side effects of immune suppressants on immune rejection have become increasingly apparent after keratoplasty. To find out new alternative immunotherapy strategies, we studied the role of programmed death-1 (PD-1) and its ligand (PD-L1) co-stimulatory pathway in inducing immune tolerance of rat keratoplasty.Methods: The PD-L1 protein was constitutively overexpressed via lentiviral transduction in bone marrow-derived dendritic cells (BMDCs) from rats, then infused via the tail vein into rats before undergoing keratoplasty. Western blot analysis of PD-L1 protein confirmed the effectiveness of lentivirus-mediated. The phenotype of immature BMDC was confirmed by flow cytometry analysis with CD80, CD86, CD11c and MHC-II antibodies. To investigate the mechanism of the immune tolerance induced by BMDCs transfusion, PD-L1, IFN-gamma and IL-17 in serum and cell culture supernatant were assessed by ELISA and qPCR.Results: After LPS stimulation, immature dendritic cells with over-expression of PD-L1 still showed high expression of PD-L1(p < 0.001), and low expression of IL-17 and IFN-gamma (p < 0.001), which reduced neo-vascularization (p < 0.05), and prolonged the survival after corneal implants.Conclusion: Immature DC cells with overexpression of PD-L1 have low ability to activate T cells ,which is a potential treatment for avoiding graft rejection by promoting natural immunosuppression. This cellular treat-ment is expected to reduce the use of immune suppressants and the occurrence of side effects.

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