title: Role of capsule and O antigen in resistance of Klebsiella pneumoniae to serum bactericidal activity.
abstract: The ability of Klebsiella pneumoniae strains to resist the bactericidal activity of serum was quantitated. The K. pneumoniae strains tested included mutants lacking the capsular polysaccharide and mutants having a modified lipopolysaccharide structure. The last mutants were obtained as phage-resistant mutants, and their lipopolysaccharide was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and chemical analysis. Serum-resistant mutants derived from phage-resistant mutants (lipopolysaccharide mutants) were also characterized. Resistance to the bactericidal activity of complement was mediated by the lipopolysaccharide, especially by the O-antigen polysaccharide chains. The capsular polysaccharide seemed not to play any important role in resistance to serum bactericidal activity in this bacterium.
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D000942:Antigens, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D001435:Bacteriophages / Q000254:growth & development; D001770:Blood Bactericidal Activity; D007711:Klebsiella pneumoniae / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology*; D008970:Molecular Weight; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D011817:Rabbits
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial