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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Adenoviridae, Animals, Diabetes Mellitus, Experimental, Gene Expression, Genetic Vectors, Islets of Langerhans Transplantation, Mice, Mice, Inbred DBA, Transduction, Genetic.
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Does ex vivo adenovirus-mediated gene delivery lead to long-term expression in pancreatic islet transplants? Context: Replication-deficient adenovirus, one of the most efficient vectors in gene therapy, has been limited by transient transgene expression due to its episomal location and loss during cell division, as well as a host immune response against viral proteins. Murine pancreatic islets were infected ex vivo with ad5-cytomegalovirus (CMV)-beta-galactosidase and transplanted into diabetic recipients with normalization of glucose metabolism. High levels of beta-galactosidase activity were detectable histologically for at least 20 weeks after transplant, and beta-galactosidase and viral mRNA were also present that long. Sera from transplanted animals did not significantly inhibit ad5-CMV-interleukin-2-Ig infection of HeLa cells in vitro, whereas sera from intravenously delivered ad5-CMV-beta-galactosidase drastically diminished HeLa cell infection, suggesting the presence of reduced levels of antibodies in transplanted animals as compared with intravenously infected animals. Immunofluorescent staining of islet isografts infected with ad5-CMV-beta-galactosidase revealed the presence of CD8+ and CD4+ T lymphocytes at all time points, however, no islet destruction was seen.
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Treatment of islet isografts ex vivo with ad5-CMV-beta-galactosidase results in prolonged transgene expression, possibly due to an attenuated immune response against adenovirus. Final Decision: yes