Lipopolysaccharide O1 Antigen Contributes to the Virulence in Klebsiella pneumoniae Causing Pyogenic Liver Abscess
Figure 5
Sensitivities of the wbbO-mutant strains to serum killing, complement C3 deposition, and phagocytosis by Dictyostelium.
A, Growth rates in LB broth of the K. pneumoniae wild-type, wbbO mutants, wbbO complementation strains, and the wbbO mutants with the GFP expression plasmid strains . The data represent the means of three independent trials; the error bars represent the standard deviations. ** P<0.01 by Student's t test (comparing the wb cluster-complemented wbbO mutant vs. the wild-type or wbbO mutant strains). B, Serum sensitivity assays of resistance to killing by nonimmune healthy human serum, comparing the wild-type, the wbbO mutant, and wbbO complementation strains. The data represent the means of three independent trials; the error bars represent the standard deviations. The average survival ratio ≥1 corresponds to serum resistance. ** P<0.01 or * P<0.05 by Student's t test (comparing wbbO mutant strains vs. the wild-type or the wb cluster-complemented wbbO mutant). C, Western blot analysis of complement C3 deposition. Samples were exposed to serum for 1 min. D, Resistance to phagocytosis in the K. pneumoniae wild-type and wbbO mutant strains by plaque assays. Pictured assay used 5000 Dictyostelium cells per test. Non-encapsulated mutants were permissive for Dictyostelium growth and were used as positive controls.