Fas ligand gene transfer to renal allografts in rats: Effects on allograft survival

Background. Fas ligand (FasL) induces apoptosis of cells bearing its receptor Fas, and has been shown to be important in T-cell development and regulation and in immune privilege. We hypothesized that FsaL expression by renal allografts might provide protection from rejection. Methods. The murine FasL cDNA was cloned into a replication-defective adenovirus (AdV-FasL). Protein expression was confirmed by immunostaining of AdV-FasL-transduced HeLa cells. Allogeneic kidney transplants were performed between WF (RT1(u)) donors and Lewis (RT¹) recipients. Donor kidneys were perfused in situ with saline alone (control), or 9 x 10⁹ plaque-forming units of AdV-FasL. One native kidney was removed at the time of transplant and the other at 6 or 7 days. Uremic death was the endpoint, and deaths within 7 days of transplant were excluded. Transduced allografts were stained for FasL expression using a monoclonal antibody and tested for FasL mRNA production by reverse transcriptase-polymerase chain reaction and Northern blotting. Results. Immunostaining of AdV-FasL-transduced allografts demonstrated efficient gene transfer lasting approximately 2 weeks, and FasL mRNA production in the AdV- FasL-transduced allografts was confirmed by Northern blotting and reverse transcriptase-polymerase chain reaction. Mean survival of animals with AdV- FasL-transduced renal allografts was 27.8 days vs. 11.6 days in control animals (P<0.05). Conclusions. (1) Adenoviral vectors can successfully transduce rat kidneys with the FasL cDNA. (2) FasL gene transfer prolongs rat renal allograft survival.