title: Role of lipopolysaccharide and complement in susceptibility of Klebsiella pneumoniae to nonimmune serum.
abstract: The role of lipopolysaccharide (LPS) in the susceptibility of Klebsiella pneumoniae to serum and the mechanism of complement activation by serum-susceptible (SerS) strains were investigated. The classical and alternative complement pathways are involved in serum killing of susceptible K. pneumoniae strains. The LPS composition seems to play a very important role in the serum bactericidal reaction, while capsular polysaccharide from this bacterium does not play any role. High-molecular-weight LPS from serum-resistant (Serr) K. pneumoniae strains was able to inhibit completely the serum bactericidal activity. LPS from SerS K. pneumoniae strains was not able to inhibit completely the serum bactericidal activity; low-molecular-weight LPS from Serr K. pneumoniae strains could not either. All these findings suggested that LPS composition, especially the O-antigen polysaccharide chains, contributes to the susceptibility of K. pneumoniae strains to complement-mediated serum bactericidal activity.
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Barcelona, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Ciurana
authors.forename: J M
authors.initials: JM
authors.lastname: Tomás
mesh_terms: D001770:Blood Bactericidal Activity; D003167:Complement Activation; D007711:Klebsiella pneumoniae / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology*; D008970:Molecular Weight; D011135:Polysaccharides, Bacterial / Q000276:immunology*
chemical_list: D008070:Lipopolysaccharides; D011135:Polysaccharides, Bacterial