title: Manno(rhamno)biose-containing capsular polysaccharides of Klebsiella pneumoniae enhance opsono-stimulation of human polymorphonuclear leukocytes.
abstract: We tested the relationship between the capsular and the O-antigen structures and the ability of bacteria to trigger respiratory burst in human polymorphonuclear leukocytes (PMNL). Capsulated and non-capsulated variants as well as capsule-switched derivatives of Klebsiella serotypes bearing or lacking manno(rhamno)biose repeats in their capsular polysaccharides and expressing either mannose-rich or mannose-poor O antigens were tested for their ability to induce respiratory burst and survive in human PMNL. Luminol-enhanced chemiluminescence (CL) was measured to quantify respiratory burst. Intracellular survival was quantified by determining the viable counts of intracellular bacteria. K serotypes and the capsule-switched derivative lacking manno(rhamno)biose induced significantly lower CL than those expressing manno(rhamno)biose. Manno(rhamno)biose-lacking serotypes survived in the cells significantly better than serotypes expressing these repeats. C1q depletion did not affect CL induced by the manno(rhamno)biose-containing serotype, whereas factor B depletion revealed a significantly reduced CL. Likewise, EGTA in the presence of Mg(2+) significantly decreased CL, but the values were higher than those induced by the bacterium opsonized with factor B-depleted serum. In the presence of EGTA, Mg(2+)-treated factor B-depleted serum revealed a significant reduction in the CL response compared with the responses induced by opsonization with factor B-depleted serum alone. These results indicate, in addition to the alternative pathway, a manno(rhamno)biose pattern recognition of Klebsiella by PMNL probably by the complement lectin pathway.
authors.affiliation: Institute for Infection Medicine, Faculty of Medicine, University of Kiel, Kiel, Germany. sahly@labor-lademannbogen.de
authors.forename: Hany
authors.initials: H
authors.lastname: Sahly
authors.forename: Yona
authors.initials: Y
authors.lastname: Keisari
authors.forename: Itzhak
authors.initials: I
authors.lastname: Ofek
mesh_terms: D000328:Adult; D016667:Bacterial Capsules / Q000737:chemistry*; D006801:Humans; D007710:Klebsiella Infections / Q000276:immunology* / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000276:immunology*; D008351:Mannans / Q000276:immunology* / Q000378:metabolism; D008875:Middle Aged; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology*; D019081:O Antigens / Q000737:chemistry / Q000276:immunology*; D009895:Opsonin Proteins / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects; D016897:Respiratory Burst / Q000276:immunology; D012210:Rhamnose / Q000276:immunology*
chemical_list: D008351:Mannans; D019081:O Antigens; D009895:Opsonin Proteins; C014647:mannobiose; C097323:polymannose; D012210:Rhamnose