FIG 13.

Flow cytometry of T cells isolated from WT Y. pestis CO92- and CO92 mutant-immunized mice after ex vivo pulsing with plague bacterium antigens. T cells from animals infected with WT CO92 or the Δlpp Δpla double mutant or uninfected mice (see the legend to Fig. 12) were cultured with pulsed APCs for 5 days. Cells were then stained and read on a flow cytometer (LSR II Fortessa), and the data were analyzed by using FACS Diva software. T cells were stained on days 14 (CD4⁺⁰ cells [A] and CD8⁺ cells [C]) and 60 (CD4⁺ cells [B] and CD8⁺ cells [D]). These data represent averages from two independent experiments. Data were analyzed by Tukey's post hoc test with one-way ANOVA, and a P value of ≤0.05 was considered significant. *, statistical significance (P < 0.05) between control mice and WT CO92-infected or Δlpp Δpla double mutant-infected mice.