Adenovirus-mediated CTLA4-Ig and FasL gene transfer induces long-term survival of renal allografts in rats

Objective To investigate the potential role of adenovirus-CTLA4-Ig and adenovirus-FasL recombinant in inducing transplantation tolerance using renal-graft model and its related mecha-nisms. Methods Allogeneic kidney transplants were performed between SD donors and Wistar recipients. The experimental rats were divided into 4 groups. In Ad-CTLA4-Ig group and Ad-CTLA4-Ig + Ad-FasL group, the donor kidney of the SD rats was locally transfected by Ad-CTLA4-Ig and Ad-CTLA4-Ig + Ad-FasL with the dose of 1 × 109-5 × 109 PFUml respectively and then transplanted to the recipient Wistar rats. In control group, the kidneys of the SD rats were directly transplanted to Wistar rats without any thera-py. The rats treated with Ad-EGFP served as empty vector group. After kidney transplantation, the survival time and the kidney function in each group were observed. Kidney allografts were evaluated by HE staining and immunohistochemical staining. The pathological features and ultrastructures of the grafts were ob-served. Results The survival time of allografts were prolonged significantly in recipients receiving Ad-CT-LA4-Ig + Ad-FasL with a mean survival time of (64.67 ± 6.41) days ,significantly longer than that in Ad-CTLA4-Ig treated group (31.33±6.77) days,control group (8.17 ± 1.17) days and empty vector group (8.00 ± 1.55) days (P ＜ 0.01). After transplantation, the levels of creatinine in serum were significantly higher in control group and empety vector group than in Ad-CTLA4-Ig + Ad-FasL treated group and Ad-CTLA4-Ig treated group. Conclusion Adenoviral vectors can be successfully transduced into rat kidneys with the CTLA4-Ig and FasL cDNA. Ad-mediated transduction of the CTLA4-Ig and FasL gene can signifi-cantly prolong the survival of rat renal allograft. The induced tolerance is donor specific, and may result from regulatory T cells and the deletion of alloreactive T cells. Key words: Renal transplantation; Adenovirus; Gene therapy; CTLA4 Ig; FasL