title: Relative Contribution of P5 and Hap Surface Proteins to Nontypable Haemophilus influenzae Interplay with the Host Upper and Lower Airways.
abstract: Nontypable Haemophilus influenzae (NTHi) is a major cause of opportunistic respiratory tract disease, and initiates infection by colonizing the nasopharynx. Bacterial surface proteins play determining roles in the NTHi-airways interplay, but their specific and relative contribution to colonization and infection of the respiratory tract has not been addressed comprehensively. In this study, we focused on the ompP5 and hap genes, present in all H. influenzae genome sequenced isolates, and encoding the P5 and Hap surface proteins, respectively. We employed isogenic single and double mutants of the ompP5 and hap genes generated in the pathogenic strain NTHi375 to evaluate P5 and Hap contribution to biofilm growth under continuous flow, to NTHi adhesion, and invasion/phagocytosis on nasal, pharyngeal, bronchial, alveolar cultured epithelial cells and alveolar macrophages, and to NTHi murine pulmonary infection. We show that P5 is not required for bacterial biofilm growth, but it is involved in NTHi interplay with respiratory cells and in mouse lung infection. Mechanistically, P5NTHi375 is not a ligand for CEACAM1 or α5 integrin receptors. Hap involvement in NTHi375-host interaction was shown to be limited, despite promoting bacterial cell adhesion when expressed in H. influenzae RdKW20. We also show that Hap does not contribute to bacterial biofilm growth, and that its absence partially restores the deficiency in lung infection observed for the ΔompP5 mutant. Altogether, this work frames the relative importance of the P5 and Hap surface proteins in NTHi virulence.
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Euba
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Moleres
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain; Laboratory Microbial Pathogenesis, Fundación Investigación Sanitaria Illes Balears (FISIB), CSIC-Govern Illes Balears, Bunyola, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Viadas
authors.affiliation: Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain.
authors.forename: Igor
authors.initials: I
authors.lastname: Ruiz de los Mozos
authors.affiliation: Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain.
authors.forename: Jaione
authors.initials: J
authors.lastname: Valle
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Laboratory Microbial Pathogenesis, Fundación Investigación Sanitaria Illes Balears (FISIB), CSIC-Govern Illes Balears, Bunyola, Spain; Centre for Infection and Immunity, Queen's University Belfast, Belfast, United Kingdom.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Bengoechea
authors.affiliation: Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain; Instituto de Agrobiotecnología, CSIC-Universidad Pública Navarra-Gobierno Navarra, Mutilva, Spain; Laboratory Microbial Pathogenesis, Fundación Investigación Sanitaria Illes Balears (FISIB), CSIC-Govern Illes Balears, Bunyola, Spain.
authors.forename: Junkal
authors.initials: J
authors.lastname: Garmendia
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001422:Bacterial Adhesion; D058491:Bacterial Load; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D015373:Bacterial Typing Techniques; D018441:Biofilms / Q000254:growth & development; D015815:Cell Adhesion Molecules / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology / Q000473:pathology; D005260:Female; D005798:Genes, Bacterial; D006031:Glycosylation; D006192:Haemophilus Infections / Q000382:microbiology* / Q000473:pathology; D006193:Haemophilus influenzae / Q000235:genetics / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D039482:Integrin alpha5 / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000382:microbiology / Q000473:pathology; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012137:Respiratory System / Q000382:microbiology* / Q000473:pathology; D012141:Respiratory Tract Infections / Q000382:microbiology* / Q000473:pathology; D012697:Serine Endopeptidases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C069847:CD66 antigens; D015815:Cell Adhesion Molecules; C091552:Hap protein, Hemophilus influenzae; D039482:Integrin alpha5; D012697:Serine Endopeptidases