TLR9-signaling pathways are involved in Kilham rat virus-induced autoimmune diabetes in the biobreeding diabetes-resistant rat
Department of Medicine, Division of Infectious Diseases and Immunology; Department of Medicine, Division of Diabetes; Department of Medicine, Division of Endocrinology and Metabolism
Animals; B-Lymphocytes; Breeding; Cells, Cultured; Chloroquine; DNA, Viral; Diabetes Mellitus, Type 1; Disease Susceptibility; Female; Genome, Viral; *Health; Interleukin-12 Subunit p40; Interleukin-6; Macrophages; Male; Membrane Proteins; NF-kappa B; Parvovirus; Rats; *Signal Transduction; Spleen; Toll-Like Receptor 9; Tumor Necrosis Factor-alpha
Life Sciences | Medicine and Health Sciences
Viral infections are associated epidemiologically with the expression of type 1 diabetes in humans, but the mechanisms underlying this putative association are unknown. To investigate the role of viruses in diabetes, we used a model of viral induction of autoimmune diabetes in genetically susceptible biobreeding diabetes-resistant (BBDR) rats. BBDR rats do not develop diabetes in viral-Ab-free environments, but approximately 25% of animals infected with the parvovirus Kilham rat virus (KRV) develop autoimmune diabetes via a mechanism that does not involve beta cell infection. Using this model, we recently documented that TLR agonists synergize with KRV infection and increase disease penetrance. We now report that KRV itself activates innate immunity through TLR ligation. We show that KRV infection strongly stimulates BBDR splenocytes to produce the proinflammatory cytokines IL-6 and IL-12p40 but not TNF-alpha. KRV infection induces high levels of IL-12p40 by splenic B cells and Flt-3-ligand-induced bone marrow-derived dendritic cells (DCs) but only low levels of IL-12p40 production by thioglycolate-elicited peritoneal macrophages or GM-CSF plus IL-4-induced bone marrow-derived DCs. KRV-induced cytokine production is blocked by pharmacological inhibitors of protein kinase R and NF-kappaB. Genomic KRV DNA also induces BBDR splenocytes and Flt-3L-induced DCs from wild-type but not TLR9-deficient mice to produce IL-12p40; KRV-induced up-regulation of B lymphocytes can be blocked by TLR9 antagonists including inhibitory CpG and chloroquine. Administration of chloroquine to virus-infected BBDR rats decreases the incidence of diabetes and decreases blood levels of IL-12p40. Our data implicate the TLR9-signaling pathway in KRV-induced innate immune activation and autoimmune diabetes in the BBDR rat.
J Immunol. 2007 Jan 15;178(2):693-701.
Journal of immunology (Baltimore, Md. : 1950)
Zipris, Danny; Lien, Egil; Nair, Anjali; Xie, Jenny X.; Greiner, Dale L.; Mordes, John P.; and Rossini, Aldo A., "TLR9-signaling pathways are involved in Kilham rat virus-induced autoimmune diabetes in the biobreeding diabetes-resistant rat" (2007). Open Access Articles. 1299.