Interleukin-4 or interleukin-10 expressed from adenovirus-transduced syngeneic islet grafts fails to prevent beta cell destruction in diabetic NOD mice

BACKGROUND: We performed ex vivo adenoviral gene transfer in a mouse pancreatic islet transplant model to test the efficacy of this expression system. We then determined whether adenoviral-mediated expression of mouse interleukin (IL) 4 or IL-10 from transduced syngeneic islet grafts could prevent disease recurrence in diabetic nonobese diabetic (NOD) mice. METHODS: An adenoviral vector expressing beta-galactosidase (AdCMV betaGal) was used to transduce BALB/c islets (2.5 x 10(3) plaque-forming units/islet), which were analyzed for glucose responsiveness, islet cell recovery, and efficiency of gene transfer. In vivo function and reporter gene expression were examined with AdCMV betaGal-transduced islet grafts in alloxan-induced diabetic syngeneic recipients. Adenoviruses expressing either IL-4 or IL-10 were used in a similar fashion to infect NOD islets, which were characterized in vitro, as well as transplanted into diabetic syngeneic recipients. RESULTS: In vitro functional studies showed no significant difference between control or transduced islets, with 50+/-4% of AdCMV betaGal-infected islet cells staining positive for beta-galactosidase. Transplant recipients became nomoglycemic within 48 hr after transplant, and, although beta-galactosidase expression decreased over time, it was detectable in the graft for up to 8 weeks. Despite the nanogram quantities of IL-4 or IL-10 produced/day from each graft equivalent in vitro, transduced and transplanted NOD islets failed to prevent disease recurrence. CONCLUSIONS: These results suggest that adenoviruses are efficient for at least medium term gene expression from islets in vivo, but neither IL-4 nor IL-10 alone can prevent autoimmune disease recurrence in NOD mice.