FIG. 6.

Whole-lung cytokine and chemokine content 24 h after inoculation. Homogenized whole lungs were assayed for CCL3, CXCL2, and the three cytokines associated with Th1-Th2 differentiation (IL-10, IL-12 p40, and IL-18) 24 h after bacterial inoculation, and results were expressed as picograms per milligram of total soluble lung protein. IL-10, IL-12, and IL-18 levels remained very low during the experimental period, and no statistically significant differences were seen. However, levels of both chemokines increased roughly 100-fold within 24 h of infection, with levels being comparable in mice infected with equal doses of either wild-type or mutant strains (P < 0.01). In animals infected with an isolethal rather than isometric dose of the Klebsiella mutant, chemokine levels were still higher, roughly 500 times levels seen in sham-infected animals (P < 0.01). For each group, n = 5; comparisons between groups were made with the Kruskal-Wallis test for non-normally distributed data. ND, none detected; n.s., not significant.