FIG. 4.

Production of IL-6 protein by lung tissue from mice infected with noncapsulated K. pneumoniae strains with different O-antigen structures as measured by a specific sandwich ELISA in the lungs of BALB/c mice (lungs of two mice per group). The data represent the results of three separate experiments. The controls consisted of mock infections without bacteria. The statistical differences for IL-6 protein production (as determined by an ANOVA test) between the O3-bearing strains are significantly greater than the differences between the O1-bearing strains (P < 0.0012).