Infection of mice with pYV+ and Δ yopH. (A) Survival curve of C57BL/6 mice upon i.v. infection with 5 × 103 or 5 × 104 pYV+, or with 5 × 104 or 5 × 106 ΔyopH (B) The bacterial numbers in the spleen of mice and total number of (C) macrophages and (D) granulocytes in the spleen was determined 24 h after infection. The data were from two independent the means ± standard deviation of at least ten mice per group. Asterisks indicate significant differences (p < 0.05, A and B, logrank test; C, Wilcoxon rank test, D and E, One-Way ANOVA with Dunnett test) between the compared groups.