Virus-induced diabetes mellitus: reovirus infection of pancreatic beta cells in mice.

Reovirus type 3, passaged in pancreatic beta-cell cultures, produced an insulitis when inoculated into 1- to 2-week-old mice. By means of a double-label antibody technique, in which we used fluorescein-labeled antibody to reovirus and rhodamine-labeled antibody to insulin, reovirus antigens were found in beta cells. By electron microscopy, viral particles in different stages of morphogenesis were observed in insulin-containing beta cells but not glucagon-containing alpha cells. The infection resulted in destruction of beta cells, reduction in the insulin content of the pancreas, and alteration in the host's capacity to respond normally to a glucose tolerance test.