Dynamics and distribution of CD8~+ Treg in rat orthotopic lung transplant recipients

Aim: To study the dynamics and distribution of CD8+ Treg in rat orthotopic lung transplant recipients.Methods: Allogeneic(n=20) ,isogeneic(n=5) orthotopic lung transplantation by cuff technique or sham operations(n=5) were performed for Lewis recipients.The rats were sacrificed at different postoperative time.Grafts or control lungs were harvested for histological evaluation.Lymphocytes in peripheral blood,spleen and local lymph nodes,and graft were acquired by centrifugation,trituration and lysis.Their phenotype and the expression of Foxp3 were analyzed by flow cytometry.Results: Typical acute rejections were observed in lung allografts.CD8+ CD45RC Treg was identified in blood and tissue.CD8+ CD45RC Treg/CD3+ and CD8+ CD45RC Treg/CD8+ in grafts and hilar lymph nodes of rats from isotransplant group were (15.88±2.72)% ,(13.88±2.81)% and (30.68±5.25)% ,(31.43±4.56)% ,which were higherthan those in allotransplant group [(11.27±3.06)% ,(9.89±1.86)% and (18.04±4.65)% ,(18.89±4.79)%] (t=2.518,2.648,4.030,4.240,P0.05) .Conclusion: CD8+ CD45RC Treg could aggregate to the grafts and local hilar lymph nodes.Lung Treg decrease in the setting of rejection.