FIG 2.

Intracellular survival of WT Y. pestis CO92 and its mutant strains in murine macrophages. RAW 264.7 macrophages were infected with the WT and its tested mutants at an MOI of 1 for 30 min. Monolayers were treated with 100 μg/ml gentamicin for 1 h to kill extracellular bacteria. At 4 h (after gentamicin treatment), macrophages were lysed and cultured on SBA plates. Three independent experiments were performed. The data were analyzed using one-way ANOVA with the Bonferroni correction, and a P value of ≤0.05 was considered significant. Asterisks, significant difference by comparison of the results for the mutants with those for WT CO92.