FAS LIGAND GENE TRANSFER TO RENAL ALLOGRAFTS IN RATS

Abstract

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 FasL 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 9×10⁹plaqueforming 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. Conclusions. (1) Adenoviral vectors can successfully transduce rat kidneys with the FasL cDNA. (2) FasL gene transfer prolongs rat renal allograft survival.