Retrovirus gag protein p30 in the islets of non-obese diabetic mice: relevance for pathogenesis of diabetes mellitus.

We investigated the presence of retroviral protein in the pancreatic islets of non-obese diabetic mice to prove that the virus-like particle observed specifically in the pancreatic Beta cell of these mice was retrovirus. Western blot analysis probed with anti-retrovirus antibody demonstrated the existence of retroviral gag (group specific antigen) protein p30 in the islets of female non-obese diabetic mice. Islets of non-obese diabetic mice which were treated with cyclophosphamide, known to accelerate the development of insulitis and diabetes mellitus, have shown both a significantly increased number of retrovirus-like particles (type C) and enhanced expression of gag protein p30, compared to those of mice not treated with cyclophosphamide. These results confirmed the presence of type C retrovirus in non-obese diabetic mouse Beta cells and suggest a role for retrovirus in the development of insulitis and diabetes in these mice.