The Reactive d-Glucopyranose Moiety of Streptozotocin Is Responsible for Activation of Macrophages and Subsequent Stimulation of CD8+ T Cells

Efficacy of inactivated vaccine against H5N1 influenza virus infection in mice with type 1 diabetes

We sought to determine susceptibility to highly pathogenic avian influenza (HPAI) H5N1 virus and to explore immune protection of inactivated H5N1 vaccine in streptozotocin-induced type 1 diabetic mice. Susceptibility of diabetic mice to an H5N1 virus was evaluated by comparing the median lethal dose (LD(50)) and the lung virus titers with those of the healthy after the viral infection. To evaluate the influence of diabetes on vaccination, diabetic and healthy mice were immunized once with an inactivated H5N1 vaccine and then challenged with a lethal dose of H5N1 virus. The antibody responses, survival rates, lung virus titers and body weight changes were tested. Mice with type 1 diabetes had higher lung virus titers and lower survival rates than healthy mice after H5N1 virus infection. Inactivated H5N1 vaccine induced protective antibody in diabetic mice, but the antibody responses were postponed and weakened. In spite of this, diabetic mice could be protected against the lethal virus challenge by a single dose of immunization when the amount of the antigen increased. These results indicated that type 1 diabetic mice were more susceptible to H5N1 influenza virus infection than healthy mice, and can be effectively protected by inactivated H5N1 vaccine with increased antigen.

Aire deficiency causes increased susceptibility to streptozotocin-induced murine type 1 diabetes

Aire-deficient mice are a model of the human monogenic disorder autoimmune polyendocrine syndrome type I (APS I) characterized by a progressive autoimmune destruction of multiple endocrine glands such as the adrenal cortex, the parathyroids and the beta-cells of the pancreas. The disease is caused by mutations in the autoimmune regulator (AIRE) gene, a putative transcription factor expressed in thymic medullary epithelial cells and in antigen-presenting cells of the myeloid lineage in peripheral lymphoid organs. As Aire(-/-) mice do not spontaneously develop endocrinopathies, we wanted to evaluate the autoimmune multiple low-dose streptozotocin (MLDSTZ) diabetes model in Aire(-/-) mice. Surprisingly, Aire heterozygote mice were most susceptible to MLDSTZ-induced diabetes, whereas Aire(-/-) mice displayed an intermediate sensitivity to diabetes. Furthermore, Aire(-/-) macrophages produced higher levels of TNF-alpha and lower levels of IL-10 following streptozotocin stimulation, and Aire(-/-) mice developed a higher frequency of islet cells autoantibodies as a sign of increased activation. However, the number of islet infiltrating F4/80(+) Aire(-/-) macrophages was significantly decreased which was attributed to an increased susceptibility to streptozotocin cytotoxicity of Aire(-/-) macrophages. In conclusion, Aire(-/-) macrophages display an increased activation after STZ stimuli, but suffer from increased susceptibility to STZ cytotoxicity. These results support an important function of Aire in the control of peripheral tolerance through myeloid antigen-presenting cells.