title: High-molecular-weight surface-exposed proteins of Haemophilus influenzae mediate binding to macrophages.
abstract: The molecular basis for direct bacteria-macrophage interactions that distinguishes nontypeable (NT) Haemophilus influenzae from type b organisms is not known. Because of similarities between filamentous hemagglutinin (FHA) adhesin of Bordetella pertussis and high-molecular-weight (HMW) proteins commonly expressed by NT H. influenzae, the role that HMW proteins play in determining NT H. influenzae-macrophage interactions was assessed. In tests with genetically engineered organisms, HMW protein-expressing bacteria bound significantly better than isogenic HMW protein-deficient bacteria to macrophages. HMW protein-dependent binding to macrophages is trypsin-sensitive, is independent of divalent cations, does not occur via the leukocyte integrin CD11b/CD18, and is not affected by galactose-containing carbohydrates. Organisms bound via HMW proteins remain largely extracellular and viable. Like FHA of Bordetella organisms, HMW proteins mediate binding of NT H. influenzae to macrophages. However, unlike the interaction determined by FHA, this interaction is characteristically one of adhesion and requires additional serum opsonization for efficient killing of bacteria by macrophages.
authors.affiliation: Division of Pediatric Infectious Diseases and Immunology, Cornell University Medical College, New York, New York.
authors.forename: G J
authors.initials: GJ
authors.lastname: Noel
authors.forename: S J
authors.initials: SJ
authors.lastname: Barenkamp
authors.forename: J W
authors.initials: JW
authors.lastname: St Geme
authors.forename: W N
authors.initials: WN
authors.lastname: Haining
authors.forename: D M
authors.initials: DM
authors.lastname: Mosser
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D006193:Haemophilus influenzae / Q000472:pathogenicity*; D006801:Humans; D066298:In Vitro Techniques; D016177:Macrophage-1 Antigen / Q000378:metabolism; D008264:Macrophages / Q000382:microbiology*; D051379:Mice; D008970:Molecular Weight
chemical_list: D001426:Bacterial Proteins; D016177:Macrophage-1 Antigen