Immunity to islet grafts transduced with adenovirus vectors does not inhibit long-term islet function

Adenoviral gene transfer is a potential ex vivo gene therapy for islet transplantation. However, the immunogenicity of adenoviral vectors can potentially impair vector efficacy in transplants where long-term gene expression is required. We investigated the effect of this antiviral immunity on vector expression and islet graft function. Syngeneic murine islets transduced with adenovirus encoding beta-galactosidase (AdCMVnt-betagal) were transplanted under the renal capsule. At different time points after transplant, blood glucose and glucose tolerance, intragraft cellular infiltration and IgG, IgM productions, and expression of transgene, cytokines and chemokines/receptors were assessed. Splenocytes and sera were analyzed to evaluate the systemic anti-adenoviral immune response. Diabetes was reversed in 1 day in recipients of a marginal amount (200) of untransduced islets, while AdCMVnt-betagal-transduced islets failed to reverse diabetes until 10 days post-transplant (p