Rotavirus Infection Accelerates Type 1 Diabetes in Mice with Established Insulitis▿
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FIG. 1.Diabetes development was accelerated by RRV infection of female (A) and male (B) NOD mice with established insulitis. Mice were inoculated orally at 12 weeks (female) or 15 weeks (male) of age with RRV, virus diluent, or cell extract and then monitored for diabetes until 34 weeks (female) or 45 weeks (male) of age. The data provided are from a single experiment that is representative of two independent experiments, each performed with similar numbers of mice.
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FIG. 2.Diabetes development was accelerated by RRV infection of female (A), male (B), or female and male (C) NOD8.3 TCR mice with established insulitis. Mice were orally inoculated at age 5 weeks with RRV or virus diluent and monitored for diabetes until 17 weeks of age. The data were compiled from four independent experiments performed over a 1-year period, each of which showed similar patterns of diabetes development. The naive NOD8.3 TCR mouse curves represent spontaneous diabetes development in the animal facility during this time.
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FIG. 3.Diabetes acceleration was of greater extent in mice showing higher titers of anti-rotavirus antibody (Ab) in serum. The diabetes curves for RRV-infected female NOD mice from Fig. 1 (A) and NOD8.3 TCR mice from Fig. 2 (B) were stratified into mice with low (1:100 to 1:400), medium (1:800 to 1:3,200), and high (1:6,400 to 1:25,600) serum antibody titers to RRV at 2 weeks after infection. Serum from one NOD8.3 TCR mouse was unavailable for antibody testing, so the results from that mouse were excluded.
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FIG. 4.Effect of exposure to mouse rotavirus EM in a natural experiment on diabetes development in NOD mice. Mice are stratified into those that seroconverted to rotavirus after possible exposure to EM (+serocon) and those that did not seroconvert (−serocon). Females had been inoculated with RRV at 4 weeks of age prior to EM exposure, whereas males had been inoculated at 4 weeks of age with control cell extract but had no previous rotavirus exposure.
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FIG. 5.Effects of RRV infection on insulitis development in NOD mice. (A) The pancreases of female NOD mice inoculated with RRV or virus diluent at 12 weeks of age were scored for insulitis at 1 and 5 weeks after infection, at the ages of 13 and 17 weeks, respectively. These data are compared to the insulitis scores at a similar age (13 weeks) in the pancreases of female NOD mice inoculated by oral gavage at 5 days of age. Nondiabetic mice only were included. (B) Pancreatic insulitis scores at 16, 20, and 52 weeks of age in male NOD mice inoculated with RRV or diluent at 15 weeks of age that had not become diabetic. As positive controls, the pancreas was collected at diabetes onset from two male NOD mice (one RRV inoculated) and analyzed for insulitis. All RRV-infected mice showed serum antibody titers of <1:50 and 1:3,200 at 1 and 5 weeks after infection, respectively. The bars indicate the means.
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FIG. 6.Effects of RRV infection on ratios of CD4+ to CD8+ T cells in islets and PLN of NOD mice. At each time point, at least 5,000 lymphocyte-sized cells were analyzed for each cell marker (as described in Materials and Methods) from the groups of mice described in Tables 4 and 5 that had not become diabetic. All RRV-inoculated mice seroconverted by 2 weeks after infection. Mice showed a geometric mean serum antibody titer of 1:2,800 at 5 weeks after infection. Error bars represent the standard error of the mean. A significant difference in ratios between RRV-infected and control mice is marked with a star (P = 0.003).
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FIG. 7.Expression of MHC-I on β cells of NOD8.3 TCR mice after RRV infection. Viable, CD45-negative islet cells were identified as β cells by their autofluorescence, as previously described (13). Groups of five to seven nondiabetic mice were analyzed at each time point. Mice showed geometric mean serum antibody titers to RRV of 1:110 and 1:730 at days 10 and 15 after RRV inoculation, respectively.
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FIG. 8.Levels of islet TNF-α mRNA following RRV infection of insulitic mice. Groups of four to six mock- and RRV-inoculated nondiabetic mice were analyzed at each time point. The data from consecutive time points were merged for simplicity. The data for RRV-infected mice are presented relative to the mean mRNA level for mock-infected mice at the same time, which was standardized to 1.0 (dotted line). Significant differences between RRV- and mock-infected mice are marked with stars (0.0033 ≤ P ≤ 0.036). Mouse serum antibody titers to RRV were similar to those described in the legends to Fig. 6 and 7.
- American Society for Microbiology
