Document Detail


Human genetic deficiencies reveal the roles of complement in the inflammatory network: lessons from nature.
MedLine Citation:
PMID:  19717455     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Complement component C5 is crucial for experimental animal inflammatory tissue damage; however, its involvement in human inflammation is incompletely understood. The responses to gram-negative bacteria were here studied taking advantage of human genetic complement-deficiencies--nature's own knockouts--including a previously undescribed C5 defect. Such deficiencies provide a unique tool for investigating the biological role of proteins. The experimental conditions allowed cross-talk between the different inflammatory pathways using a whole blood model based on the anticoagulant lepirudin, which does not interfere with the complement system. Expression of tissue factor, cell adhesion molecules, and oxidative burst depended highly on C5, mediated through the activation product C5a, whereas granulocyte enzyme release relied mainly on C3 and was C5a-independent. Release of cytokines and chemokines was mediated to varying degrees by complement and CD14; for example, interleukin (IL)-1beta and IL-8 were more dependent on complement than IFN-gamma and IL-6, which were highly dependent on CD14. IL-1 receptor antagonist (IL-1ra) and IFN-gamma inducible protein 10 (IP-10) were fully dependent on CD14 and inversely regulated by complement, that is, complement deficiency and complement inhibition enhanced their release. Granulocyte responses were mainly complement-dependent, whereas monocyte responses were more dependent on CD14. Notably, all responses were abolished by combined neutralization of complement and CD14. The present study provides important insight into the comprehensive role of complement in human inflammatory responses to gram-negative bacteria.
Authors:
Knut Tore Lappegård; Dorte Christiansen; Anne Pharo; Ebbe Billmann Thorgersen; Bernt Christian Hellerud; Julie Lindstad; Erik Waage Nielsen; Grethe Bergseth; Dag Fadnes; Tore G Abrahamsen; E Arne Høiby; Lone Schejbel; Peter Garred; John D Lambris; Morten Harboe; Tom Eirik Mollnes
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Publication Detail:
Type:  Case Reports; In Vitro; Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-08-26
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  106     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2009 Sep 
Date Detail:
Created Date:  2009-10-06     Completed Date:  2009-11-13     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  15861-6     Citation Subset:  IM    
Affiliation:
Department of Medicine, Nordland Hospital, Bodø, and University of Tromsø, Norway. knut.lappegard@nlsh.no
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Antigens, CD14 / metabolism
Case-Control Studies
Cell Adhesion / immunology
Complement Activation
Complement C2 / deficiency,  genetics
Complement C5 / deficiency,  genetics
Complement System Proteins / deficiency*,  genetics*
Escherichia coli / immunology
Female
Gram-Negative Bacteria / immunology,  pathogenicity
Humans
Immunity, Innate / genetics
Inflammation / etiology,  genetics*,  immunology*
Male
Models, Immunological
Monocytes / immunology,  microbiology
Neisseria meningitidis / immunology
Phagocytosis
Respiratory Burst / immunology
Thromboplastin / biosynthesis
Chemical
Reg. No./Substance:
0/Antigens, CD14; 0/Complement C2; 0/Complement C5; 9007-36-7/Complement System Proteins; 9035-58-9/Thromboplastin
Comments/Corrections

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