Lipopolysaccharide structure influences the macrophage response via CD14-independent and CD14-dependent pathways.
CD14, a protein expressed on the surface of monocytes and neutrophils, is a major receptor for lipopolysaccharide (LPS). Studies with normal and CD14-deficient macrophages show that responses to low concentrations of LPS require expression of CD14, whereas responses to high concentrations of LPS are CD14-independent. Since LPS isolated from different bacterial species shows structural variability, studies were performed to determine whether differences in LPS structure influence CD14-dependent and CD14-independent responses. Studies with LPS purified from Escherichia coli, Salmonella abortus subspecies equi, Salmonella minnesota, Pseudomonas aeruginosa, Neisseria meningitidis, Bacteroides fragilis, and Rhodobacter sphaeroides show that the strongest CD14-dependent responses require a typical O-antigen, long carbohydrate chains, at least 6 acyl chains in their lipid A, and 2-phosphorylated Kdo moieties; wild-type LPS lacking a typical O-antigen and containing short carbohydrate chains and 2-phosphorylated Kdo moieties induces the strongest CD14-independent response.
Gangloff
S C
SC
Department of Medicine, North Shore University Hospital/New York University School of Medicine, Manhasset 10010, USA.
Hijiya
N
N
Haziot
A
A
Goyert
S M
SM
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006090:Gram-Negative Bacteria / Q000276:immunology*; D018950:Lipopolysaccharide Receptors / Q000502:physiology*; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D008262:Macrophage Activation; D017737:Macrophages, Peritoneal / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C
D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides