Reovirus

Abstract

Initial studies examined the effect of reovirus types 1 and 3 isolated from humans. Subsequently viruses were passaged in primary b-cell cultures from suckling mice. Animals were infected with the virus. Viral infection led to reduction in pancreatic insulin levels which persisted for 2-week period and associated with abnormal levels of glucose tolerance tests. Histopathological examinations of the pancreas showed areas of focal, coagulative necrosis of some of the islets and mononuclear cell infiltrate from 5 days after infection. Electron microscopy revealed the presence of reticulogranular matrix which was characteristics of reovirus growth in the cytoplasm. Using double antibody labeling, it was possible to demonstrate the presence of reovirus antigen in insulin-containing b-cells. Mice infected with reovirus type 2, isolated from a cow, also developed diabetes as an immune-mediated syndrome. Reovirus type 2 without adaptation to-pancreatic b-cells infects islet cells and some acinar cells in newborn mice. The animals develop insulitis with hypoinsulinemia and impaired glucose tolerance in mice approximately 2 weeks after infection.