FIG. 1.

Survival data and viral burden data for wild-type (WT), CD8^−/−, and MHC class Ia^−/− C57BL/6J mice inoculated with WNV. (A) Wild-type, CD8^−/−, and MHC class Ia^−/− mice were inoculated via footpad with 10² PFU of WNV and monitored for 28 days. The survival curves were constructed using data from three to five independent experiments. The numbers of animals were n = 50 for wild-type, n = 43 for CD8^−/−, and n = 32 for MHC class Ia^−/− mice. Survival differences between wild-type and CD8^−/− or MHC class Ia^−/− mice were statistically significant (P < 0.0001). (B) Levels of viral RNA in serum. Viral RNA levels were determined from serum of wild-type or CD8^−/− mice after WNV infection at the indicated days by a real-time fluorogenic RT-PCR assay. Data are expressed as genomic equivalents of WNV RNA per milliliter of serum and reflect the average of five independent mice per time point. The dashed line represents the limit of sensitivity of the assay. (C to E) Infectious virus levels in tissues. Virus levels were measured from the spleen (C), upper (USC) and lower (LSC) halves of the spinal cord (D), and brain (E) of wild-type and CD8^−/− mice by a viral plaque assay in BHK21 cells after tissues were harvested at the indicated days after inoculation. Data are shown as the average PFU per gram of tissue or milliliter of serum and reflect five mice per time point for either wild-type or CD8^−/− mice. The dashed line represents the limit of sensitivity of the assay.