FIG. 2.

Many BAL cytokines are secreted in response to translocon-positive P. aeruginosa. The Bio-Plex suspension array system (Bio-Rad) was used to measure a panel of chemokines and cytokines in BAL fluid collected at 4 h.p.i. from C57BL/6 mice infected with 5 × 10⁴ CFU PA103 or the indicated mutant. Each point represents the value for an individual animal; lines indicate median values. Points graphed on the x axis indicate values below the detection limit of the assay. Median values differ significantly for all cytokines except MIP-1α; P values were calculated using the Kruskal-Wallis test. Dunn's multiple-comparison test was used to evaluate all pairwise comparisons. All significant differences are indicated on each graph (*, P < 0.05; **, P < 0.01; ***, P < 0.001). These results were replicated in an independent experiment in which cytokine and chemokine levels were determined using a Beadlyte 23-plex kit (Upstate) on mice infected with these same isogenic mutants (n = 5 to 6 animals per strain).