Figure 5. Brain-infiltrating leukocytes differ between acutely infected B6 and SJL mice.

Brain-infiltrating leukocytes (BILs) collected at 18 hours postinfection (hpi) using a 1.100 g/mL Percoll density gradient showed distinct forward scatter (FSC) and side scatter (SSC) profiles by flow cytometry in B6 mice (A) and SJL mice (B). Insets in A and B show density plots, highlighting the difference between B6 and SJL BILs. Gating on CD45^hi cells revealed a clear difference in the number of CD11b⁺Gr1⁺1A8⁻ inflammatory monocytes (labeled as M) in B6 mice (C, E) versus SJL mice (D, F). In contrast, the number of CD11b⁺⁺Gr1⁺1A8⁺ neutrophils (labeled as N) was slightly higher in SJL mice (D, F) than in B6 mice (C, E). The relative percent of CD45^hi cells identified as inflammatory monocytes or neutrophils is shown in (G). The difference between B6 and SJL mice was highly significant, at P<0.001. Dot plots are representative of at least 4 animals per condition in at least 5 separate experiments. The error bars in (G) are centered on the mean percent of CD45^hi BILs for the two gated populations and show the 95% CI for each group.