Pathogenesis of virus-induced diabetes in mice

Male CD-1 mice were challenged with a diabetogenic strain (E2) of coxsackievirus B4 (CVB4). At 7 weeks, 6 months, and 1 year after inoculation, mean histopathologic scores, postprandial blood glucose levels, and serum levels of antibody to islet cells were significantly elevated and mean fasting serum insulin levels significantly reduced in infected mice versus uninfected controls (P < .001 for each). At 7 weeks after infection, viral RNA, but not protein or infectious virus, was demonstrated in the pancreases of most infected mice. The pancreases of 4 of 12 and 0 of 10 infected animals were positive for viral RNA at 6 months and at 1 year after infection, respectively. Interferon-gamma-stimulated peritoneal macrophages were cytotoxic to islet cells with and without sera with high titers of islet cell autoantibody (ICA). Thus, islet cell destruction in mice infected with CVB4 strain E2 is associated with chronic islet cell inflammation, elevation of islet cell antibody, and prolonged presence of viral RNA in the pancreas. Stimulated peritoneal macrophages lyse islet cells directly and by an antibody-dependent mechanism.