FIGURE 4.

Neutrophil and macrophage influx into brain abscesses is significantly impaired in MyD88 KO mice. MyD88 KO and WT mice (n = 10 per group) were infected with S. aureus intracerebrally and sacrificed at 12 h following bacterial exposure, whereupon abscess-associated neutrophils (Gr-1⁺, CD11b⁺, and CD45^high), macrophages (Gr-1⁻, CD11b⁺, and CD45^high), and microglia (Gr-1⁻, CD11b⁺, and CD45^low) were quantitated by FACS analysis. Results are expressed as the percentage of cells normalized to WT values (set at 100%) and represent the mean ± SEM from three independent experiments. Significant differences in abscess-associated cells recovered from MyD88 KO vs WT animals are denoted by asterisks (*, p < 0.05; **, p < 0.001).