Complement activation by Pseudomonas aeruginosa biofilms

TY - JOUR

T1 - Complement activation by Pseudomonas aeruginosa biofilms

AU - Jensen, E T

AU - Kharazmi, A

AU - Garred, P

AU - Kronborg, G

AU - Fomsgaard, A

AU - Mollnes, T E

AU - Høiby, N

N1 - Keywords: Chemotaxis, Leukocyte; Complement Activation; Complement C3; Complement Factor B; Complement Pathway, Classical; Glycoproteins; Humans; Lipopolysaccharides; Neutrophils; Polysaccharides; Pseudomonas aeruginosa

PY - 1993

Y1 - 1993

N2 - In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact biofilms was submaximal. Factor B conversion was of low magnitude indicating the importance of the classical pathway. Complement activation by P. aeruginosa was inhibited by polymyxin B indicating that lipopolysaccharide (LPS) was the main mediator of complement activation. Immune complexes and massive influx of neutrophils are known to cause inflammatory changes in the lungs. P. aeruginosa persisting in biofilms may contribute to the constant inflammation taking place in the lungs of CF patients.

AB - In chronic infections, such as the bronchopulmonary Pseudomonas aeruginosa infection in cystic fibrosis (CF) patients, bacteria persist despite an intact host immune defense and frequent antibiotic treatment. An important reason for the persistence of the bacteria is their capacity for the biofilm mode of growth. In this study we investigated the role of biofilms in activation of complement, a major contributor to the inflammatory process. Complement activation by P. aeruginosa was examined in a complement consumption assay, production of C3 and factor B conversion products assessed by crossed immuno-electrophoresis, C5a generation tested by a PMN chemotactic assay, and terminal complement complex formation measured by ELISA. Two of the four assays showed that P. aeruginosa grown in biofilm activated complement less than planktonic bacteria, and all assays showed that activation by intact biofilms was submaximal. Factor B conversion was of low magnitude indicating the importance of the classical pathway. Complement activation by P. aeruginosa was inhibited by polymyxin B indicating that lipopolysaccharide (LPS) was the main mediator of complement activation. Immune complexes and massive influx of neutrophils are known to cause inflammatory changes in the lungs. P. aeruginosa persisting in biofilms may contribute to the constant inflammation taking place in the lungs of CF patients.

U2 - 10.1006/mpat.1993.1087

DO - 10.1006/mpat.1993.1087

M3 - Journal article

C2 - 8015418

SN - 0882-4010

VL - 15

SP - 377

EP - 388

JO - Microbial Pathogenesis

JF - Microbial Pathogenesis

IS - 5

ER -