Surfactant protein D binds selectively to Klebsiella pneumoniae lipopolysaccharides containing mannose-rich O-antigens.
Surfactant protein D (SP-D) plays important roles in the regulation of innate immune responses in the lung. We have previously shown that SP-D can agglutinate and enhance the macrophage-dependent killing of specific unencapsulated phase variants of Klebsiella pneumoniae. In the present studies, we used 16 clinical isolates of Klebsiella representing four O-serotypes and examined the interaction of SP-D with their isolated LPSs. Although SP-D bound to the core oligosaccharide of rough LPS from all isolates, it selectively bound to smooth forms of LPS expressed by O-serotypes with mannose-rich repeating units in their O-polysaccharides. SP-D was more potent in agglutinating unencapsulated phase variants of O-serotypes expressing these SP-D "reactive" O-polysaccharides, and more effectively inhibited the adhesion of these serotypes to lung epithelial cells. This novel anti-adhesion activity required the multimerization of trimeric SP-D subunits (dodecamers). Klebsiella serotypes expressing "nonreactive" LPS O-Ags were isolated at a significantly higher frequency from patients with K. pneumoniae. Our findings suggest that SP-D plays important roles in the clearance of opportunistic Gram-negative bacteria and contributes to known serotypic differences in the pathogenicity of Klebsiella through specific interactions with O-polysaccharides.
Sahly
Hany
H
Department of Medical Microbiology, University of Kiel, Kiel, Germany.
Ofek
Itzhak
I
Podschun
Rainer
R
Brade
Helmut
H
He
Yanchun
Y
Ullmann
Uwe
U
Crouch
Erika
E
D000371:Agglutination / Q000276:immunology; D001216:Asparagine / Q000378:metabolism; D001422:Bacterial Adhesion / Q000276:immunology; D002236:Carbohydrate Conformation; D003428:Cross Infection / Q000276:immunology / Q000382:microbiology; D006023:Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D006031:Glycosylation; D006801:Humans; D007710:Klebsiella Infections / Q000276:immunology / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000145:classification / Q000276:immunology / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000145:classification / Q000276:immunology / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism*; D019081:O Antigens / Q000378:metabolism* / Q000502:physiology; D011485:Protein Binding / Q000276:immunology; D021122:Protein Subunits; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D020545:Respiratory Mucosa / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D012703:Serotyping; D014407:Tumor Cells, Cultured
D006023:Glycoproteins; D008070:Lipopolysaccharides; D019081:O Antigens; C409028:O5-antigen lipopolysaccharide, Klebsiella; D021122:Protein Subunits; D037663:Pulmonary Surfactant-Associated Protein D; D011663:Pulmonary Surfactants; D001216:Asparagine; D008358:Mannose