Detection of endogenous retrovirus antigens in NOD mouse pancreatic β-cells

We characterized C-type retroviruses expressed in the pancreatic beta-cells of non-obese diabetic (NOD) mice by immunohistochemical techniques and by inhibiting the production of viral particles using antisense oligonucleotides. Some cells in the pancreatic islets from both NOD and diabetes-resistant NOD-related mice (NON) reacted with a monoclonal antibody directed against the envelope protein(s) of polytropic viruses. On the other hand, NOD islet cells also showed strong immunoreactivity with an anti-gag protein monoclonal antibody and another anti-envelope protein(s) monoclonal antibody that is specific for xenotropic viruses. In antisense oligodeoxynucleotide inhibition assays, a xenotropic virus-specific phosphorothionate-particles antisense oligodeoxynucleotide significantly inhibited the occurrence of C-type virus particles in NOD mouse islet beta-cells. Therefore, C-type retrovirus-like particles expressed in NOD mouse pancreatic beta-cells were considered to be endogenous xenotropic virus. The expression of the xenotropic viral genome may be involved in the pathogenesis of the diabetic syndrome in NOD mice.