title: NADH oxidase functions as an adhesin in Streptococcus pneumoniae and elicits a protective immune response in mice.
abstract: The initial event in disease caused by S. pneumoniae is adhesion of the bacterium to respiratory epithelial cells, mediated by surface expressed molecules including cell-wall proteins. NADH oxidase (NOX), which reduces free oxygen to water in the cytoplasm, was identified in a non-lectin enriched pneumococcal cell-wall fraction. Recombinant NOX (rNOX) was screened with sera obtained longitudinally from children and demonstrated age-dependent immunogenicity. NOX ablation in S. pneumoniae significantly reduced bacterial adhesion to A549 epithelial cells in vitro and their virulence in the intranasal or intraperitoneal challenge models in mice, compared to the parental strain. Supplementation of Δnox WU2 with the nox gene restored its virulence. Saturation of A549 target cells with rNOX or neutralization of cell-wall residing NOX using anti-rNOX antiserum decreased adhesion to A549 cells. rNOX-binding phages inhibited bacterial adhesion. Moreover, peptides derived from the human proteins contactin 4, chondroitin 4 sulfotraferase and laminin5, homologous to the insert peptides in the neutralizing phages, inhibited bacterial adhesion to the A549 cells. Furthermore, rNOX immunization of mice elicited a protective immune response to intranasal or intraperitoneal S. pneumoniae challenge, whereas pneumococcal virulence was neutralized by anti-rNOX antiserum prior to intraperitoneal challenge. Our results suggest that in addition to its enzymatic activity, NOX contributes to S. pneumoniae virulence as a putative adhesin and thus peptides derived from its target molecules may be considered for the treatment of pneumococcal infections. Finally, rNOX elicited a protective immune response in both aerobic and anaerobic environments, which renders NOX a candidate for future pneumococcal vaccine.
authors.affiliation: Pediatric Infectious Disease Unit, Soroka University Medical Center, Beer Sheva, Israel.
authors.forename: Lena
authors.initials: L
authors.lastname: Muchnik
authors.forename: Asad
authors.initials: A
authors.lastname: Adawi
authors.forename: Ariel
authors.initials: A
authors.lastname: Ohayon
authors.forename: Shahar
authors.initials: S
authors.lastname: Dotan
authors.forename: Itai
authors.initials: I
authors.lastname: Malka
authors.forename: Shalhevet
authors.initials: S
authors.lastname: Azriel
authors.forename: Marilou
authors.initials: M
authors.lastname: Shagan
authors.forename: Maxim
authors.initials: M
authors.lastname: Portnoi
authors.forename: Daniel
authors.initials: D
authors.lastname: Kafka
authors.forename: Hannie
authors.initials: H
authors.lastname: Nahmani
authors.forename: Angel
authors.initials: A
authors.lastname: Porgador
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Gershoni
authors.forename: Johnatan M
authors.initials: JM
authors.lastname: Gershoni
authors.forename: Donald A
authors.initials: DA
authors.lastname: Morrison
authors.forename: Andrea
authors.initials: A
authors.lastname: Mitchell
authors.forename: Michael
authors.initials: M
authors.lastname: Tal
authors.forename: Ronald
authors.initials: R
authors.lastname: Ellis
authors.forename: Ron
authors.initials: R
authors.lastname: Dagan
authors.forename: Yaffa Mizrachi
authors.initials: YM
authors.lastname: Nebenzahl
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000332:Aerobiosis; D000375:Aging / Q000276:immunology; D000693:Anaerobiosis; D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D002675:Child, Preschool; D005260:Female; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006801:Humans; D007109:Immunity; D007223:Infant; D051379:Mice; D009097:Multienzyme Complexes / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000276:immunology
chemical_list: D018829:Adhesins, Bacterial; D001428:Bacterial Vaccines; D009097:Multienzyme Complexes; D010455:Peptides; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases