Figure 4

Tregs are present in the CNS of 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 mononuclear cells were collected, and flow cytometry was performed for various cell markers. Cells were gated on the CD45⁺ population as shown in Figure 1. (A) Representative scatter plot is shown for Treg markers, Foxp3 and CD25, on cells gated for the CD4⁺ population from a WNV-inoculated mouse. (B) The numbers of CD4⁺/Foxp3⁺/CD25⁺ cells per brain are shown at various times post-inoculation. Each data point represents an individual mouse, and solid horizontal lines represent the geometric means. Open symbols indicate mice that showed clinical signs of disease during acute illness. The data point on the x-axis is negative. Two independent studies were performed for 1 and 12 wpi, and these data were analyzed by Mann-Whitney U tests with P values indicated by: 0.001 < ** ≤0.01. (C) The percentage of CD4⁺ cells expressing Foxp3 and CD25 in the brains of WNV-inoculated mice is shown at various times post-inoculation. Each data point represents an individual mouse, and solid horizontal lines represent the means. The groups from each time point were significantly different by a Kruskal-Wallis test (P = 0.05), and the group at 12 wpi was significantly different from the groups at 1, 2 and 4 wpi by Mann-Whitney U tests (P < 0.05).