FIGURE 4. Enhanced control of virulent L. monocytogenes in SPexp mice.

(A) Experimental design. SPfree and SPexp B6 mice (without attenuated L. monocytogenes infection) were challenged with 8 × 10⁴ CFUs virulent L. monocytogenes 5 d after last infection, and mortality was monitored. Bacterial burden was assessed within spleen and liver 2 d after virulent L. monocytogenes challenge. (B and C) Clinical score (B) and L. monocytogenes CFUs per gram of (left) spleen and (right) liver (C) 2 d after challenge. (D) Mortality of mice after challenge. Data are representative of at least three independent experiments with five mice per group. Error bars represent SEM. *p < 0.05, **p < 0.01, ****p < 0.0001.