Figure 6

Administration of poly IC at 1 day prior to or 8 days post TMEV infection into SJL mice. Mice were intraperitoneally injected with either PBS or 50 μg of poly IC (Sigma) in 100 μl at day -1 or +8 relative to viral infection. (A) Frequency and severity of demyelinating disease in SJL mice after ip injection with poly IC at 1 day prior to (n = 10) or 8 days post (n = 10) TMEV infection were monitored for 63 days after TMEV infection. Statistically significant differences in Student's t-test were indicated with asterisks (*, P < 0.05). Paired t-tests (two-tailed) between 20-63 dpi indicated that the difference between untreated and pretreated groups was very significant (P < 0.0026) and the difference between untreated and post-treated groups was significant (P < 0.0189). (B) Viral persistence levels in the brain (BR) and spinal cord (SC) of infected mice at 14 dpi were determined using quantitative PCR. Data are expressed by fold induction after normalization to the GAPDH mRNA levels. The values given are means ± standard deviations of triplicates. Statistically significant differences were indicated with asterisks (*, P < 0.05; **, P < 0.01; ***, P < 0.001). (C and D) CNS-infiltrating mononuclear cells from SJL mice with treatment of poly IC at -1 day or +8 days post TMEV infection were shown. Numbers in FACS plots represent percentages in the total CNS-infiltrating cells. Data are representative of three experiments using three mice per group. (E) Levels of IFN-γ producing CD4⁺ cells in the CNS were determined by intracellular staining after stimulation for 6 hours with 2 μM CD4 epitope peptides at 28 dpi. (F) Levels of IFN-γ producing CD8⁺ cells in the CNS were determined by intracellular staining after stimulation for 6 hours with 2 μM CD8 viral epitope peptides at 28 dpi. Numbers in the FACS plots represent percentages in total CD4 or CD8 cells. Data are representative of three experiments using three mice per group.