Figure 7.

WNV-specific CD8⁺ T cells persist in brains for up to 16 wpi in WNV-inoculated mice. Adult, female B6 mice were inoculated SC with diluent (mock) or 10³ PFU of WNV in the left rear footpad. At various times post-inoculation, two mock-inoculated and four WNV-inoculated mice were sacrificed and perfused with perfusion buffer. CNS and splenic mononuclear cells were collected, and flow cytometry was performed for CD45, CD8 and MHC class I dimer for a WNV dominant epitope (SSVWNATTA) and an irrelevant epitope. Cells were gated on the CD45⁺ population as shown in Figure 1. Representative scatter plots are shown for CD8 and WNV-specific dimer in the (A) brain and (B) spleen from WNV-inoculated mice. The numbers of CD8⁺ T cells in the (C) brain and the percentages of CD8⁺ T cells in the (D) spleen that were specific for the WNV epitope are reported. Values for specific CD8⁺ T cells were calculated by subtracting background values for the irrelevant peptide from values for the WNV peptide. Each data point represents an individual mouse, and solid horizontal lines represent the geometric means in (C) and means in (D). Open symbols indicate mice that displayed signs of disease during acute illness. Data points on the x-axis are negative. Two independent studies were performed, and these data were analyzed by Mann-Whitney U tests with P values indicated by: 0.001 < ** ≤0.01 and 0.01 < * ≤0.05.