title: CipA of Acinetobacter baumannii Is a Novel Plasminogen Binding and Complement Inhibitory Protein.
abstract: Acinetobacter baumannii is an emerging opportunistic pathogen, responsible for up to 10% of gram-negative, nosocomial infections. The global increase of multidrug-resistant and pan-resistant Acinetobacter isolates presents clinicians with formidable challenges. To establish a persistent infection,A. baumannii must overcome the detrimental effects of complement as the first line of defense against invading microorganisms. However, the immune evasion principles underlying serum resistance inA. baumannii remain elusive. Here, we identified a novel plasminogen-binding protein, termed CipA. Bound plasminogen, upon conversion to active plasmin, degraded fibrinogen and complement C3b and contributed to serum resistance. Furthermore, CipA directly inhibited the alternative pathway of complement in vitro, irrespective of its ability to bind plasminogen. A CipA-deficient mutant was efficiently killed by human serum and showed a defect in the penetration of endothelial monolayers, demonstrating that CipA is a novel multifunctional protein that contributes to the pathogenesis ofA. baumannii.
authors.affiliation: Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt.
authors.forename: Arno
authors.initials: A
authors.lastname: Koenigs
authors.affiliation: Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University, Frankfurt.
authors.forename: Julia
authors.initials: J
authors.lastname: Stahl
authors.affiliation: Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University, Frankfurt.
authors.forename: Beate
authors.initials: B
authors.lastname: Averhoff
authors.affiliation: Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt.
authors.forename: Stephan
authors.initials: S
authors.lastname: Göttig
authors.affiliation: Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Wichelhaus
authors.affiliation: Institute of Immunology, University Hospital of Heidelberg.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Wallich
authors.affiliation: Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology Friedrich Schiller University, Jena, Germany.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Zipfel
authors.affiliation: Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt.
authors.forename: Peter
authors.initials: P
authors.lastname: Kraiczy
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry; D003165:Complement System Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D010958:Plasminogen / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D001426:Bacterial Proteins; D010958:Plasminogen; D003165:Complement System Proteins
keywords: Acinetobacter baumannii; complement; fibrinolysis; innate immunity; plasminogen; resistance