Abstract
Purpose :
Graft rejection remains the leading cause of allograft failure in corneal transplantation. Plasmacytoid dendritic cells (pDCs) are implicated in the maintenance of immune tolerance in other models. Herein, we tested the hypothesis that adoptive transfer of pDCs can promote allograft survival via inducing immune tolerance, using an experimental allogenic corneal transplantation model
Methods :
Allogenic corneal transplantation was established using BALB/c recipients and C57BL/6 donors. Adoptive transfer of sorted splenic allo-pDCs or saline were performed using fibrin sealant at d1 post-surgery. Anergic T cells, regulatory T cells (Tregs), Th1, and Th17 cells in draining lymph nodes (dLNs), and infiltrating leukocytes and T cells in corneas, were detected via flow cytometry at d14 post-transfer. Grafts was assessed twice weekly for 70 days with slit-lamp to score graft neovascularization (NV, 0-8+ scale), opacity (0-5+ scale), and rejection (graft opacity≥ score 3). Rejection-free graft survival was evaluated by Kaplan-Meier survival curves followed by log-rank test; unpaired t-test was used for comparisons.
Results :
pDCs induced anergic CD4+T cells (CTLA-4+: 1.6-fold, PD-1+: 1.8-fold, LAG-3+: 4.6-fold, compared to the saline group; n=3, all p<0.05), and expanded the Foxp3+CD4+Tregs compartment (2.5-fold; n=3, p<0.001), while they had no effect on IFNγ+CD4+ Th1 and IL17+CD4+ Th17 (1.2-fold and 1.1-fold respectively; n=3, both p>0.05) in dLNs. In addition, pDCs ameliorated infiltration of CD45+ leukocytes and CD3+ T cells in corneal beds (CD45+: 87.5%, CD3+: 79.0% decrease compared to saline group; n=3, both p<0.05) and grafts (CD45+: 75.8%, CD3+: 71.9% decrease; n=3, both p<0.01). Moreover, pDCs suppressed corneal NV from d7 until d70 (score 2.8±0.34 SEM to 5.4±0.36, n=12 for pDCs transfer group vs 4.0±0.23 to 6.4±0.22, n=11 for saline control group; p<0.05 for all timepoints). Further, pDCs alleviated graft opacity from d14 until d70 (score 0.4±0.15 to 1.5±0.33, n=12 vs 1.1±0.21 to 3.5±0.45, n=11; all p<0.05), and improved survival rate of grafts (83.3%, n=12 vs 36.4%, n=11; p<0.01) through the end of 70 days.
Conclusions :
Adoptive transfer of pDC promote survival of corneal allograft, which is associated with T cell tolerance, suggesting the translational potential of cell-based pDC therapy use in corneal transplantation
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.