Effects Of Direct Transfer Of α-melanocyte Stimulating Hormone Gene Into Allograft And B7-H1 Gene Modified Dendritic Cells On The Allograft Rejection

Objective To investigate the direct transfection of α-MSH gene into allografts and B7-H1 gene modified DC to prevent graft rejection. Methods This study used the heterotopic cervical allo-cardiac transplantation model. rAAV carrying α-MSH gene (rAAV-α-MSH) was constructed. α-MSH gene transfected allografts by AAV vector were transplanted to the allogeneic recipients. The graft survival time was observed. The in situ expression of α-MSH in allografts was examined at different time after transplantation. The pathological damage and the levels of cytokines in allografts were examined 7 days after transplantation. rAd carrying B7-H1 gene (rAd-B7-H1) was constructed. Dendritic cell clusters were transfected with rAd-B7-H1, named B7-H1-DCs.The phenotypic characteristics were determined by fluorescent-activated cell sorter (FACS).The proliferation of T cells and the levels of the cytokines were assessed in allo-MLR. C57BL/6 mice were immunized intravenously with B7-Hl-DCs derived from BALB/c. The graft survival time was daily observed. The pathological damage and the levels of serum cytokines were examined 7 days after transplantation. Result Directly delivery of rAAV-α-MSH into the allografts could significantly prolong allograft survival. B7-H1 gene could be efficiently transferred into DCs by rAd vector. The higher expression of B7-H1 was obsevered on B7-H1-DCs. B7-H1-DCs inhibited the proliferation of T cells and the production of Th1 cytokines, and enhanced the secretion of Th2 cytokines in allo-MLR. A single systemic injection of donor-derived B7-H1-DCs to recipients at 1 week before transplantation significantly prolonged allograft survival. By transferring B7-H1-DC to recipients, the pathological damages of grafts were lightened and Th1 cytokines (IL-2, IFN-γ) in the sera decreased, while IL-10 increased 7 days after transplantation. .Conclusions Directly delivery of rAAV-α-MSH into the allografts and B7-H1 gene modified DC could significantly prolong allogeneic vascularized cardiac allograft survival.