title: Serum antibody response to Moraxella catarrhalis proteins OMP CD, OppA, Msp22, Hag, and PilA2 after nasopharyngeal colonization and acute otitis media in children.
abstract: BACKGROUND
  There is no licensed vaccine for Moraxella catarrhalis (Mcat), which is a prominent bacterium causing acute otitis media (AOM) in children and lower respiratory tract infections in adults. Nasopharyngeal (NP) colonization caused by respiratory bacteria results in natural immunization of the host. To identify Mcat antigens as vaccine candidates, we evaluated the development of naturally induced antibodies to 5 Mcat surface proteins in children 6-30 months of age during Mcat NP colonization and AOM.
  
  
  METHODS
  Human serum IgG against the recombinant Mcat proteins, outer membrane protein (OMP) CD, oligopeptide permease (Opp)A, hemagglutinin (Hag), Moraxella surface protein (Msp)22, and PilA clade 2 (PilA2) was quantitated by using an ELISA assay.
  
  
  RESULTS
  There were 223 Mcat NP colonization episodes documented in 111 (60%) of 184 children in the study. Thirty five Mcat AOM episodes occurred in 30 (16%) of 184 children. All 5 Mcat candidate vaccine antigens evaluated stimulated a significant rise in serum IgG levles over time from 6 to 36 months of age (P<0.001), with a rank order as follows: Msp22=OppA>OMP CD=Hag=PilA2. Children with no detectable Mcat NP colonization showed a higher serum IgG level against OppA, Hag, and Msp22 compared to those with Mcat NP colonization (P<0.05). Individual data showed that some children responded to AOM with an antibody increase to one or more of the studied Mcat proteins but some children failed to respond.
  
  
  CONCLUSIONS
  Serum antibody to Mcat candidate vaccine proteins OMP CD, OppA, Msp22, Hag, and PilA2 increased with age in naturally immunized children age 6-30 months following Mcat NP colonization and AOM. High antibody levels against OppA, Msp22, and Hag correlated with reduced carriage. The results support further investigation of these vaccine candidates in protecting against Mcat colonization and infection.
authors.affiliation: Rochester General Hospital Research Institute, Rochester, NY 14621, USA. Electronic address: dabin.ren@rochesterregional.org.
authors.forename: Dabin
authors.initials: D
authors.lastname: Ren
authors.affiliation: Department of Biostatistics and Computational Biology, University of Rochester Medical Center, Rochester, NY 14642, USA.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Almudevar
authors.affiliation: Clinical and Translational Research Center, School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14214, USA.
authors.forename: Timothy F
authors.initials: TF
authors.lastname: Murphy
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine University of Georgia, Athens, GA 30602, USA.
authors.forename: Eric R
authors.initials: ER
authors.lastname: Lafontaine
authors.affiliation: Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14214, USA.
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Campagnari
authors.affiliation: Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14214, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Luke-Marshall
authors.affiliation: Legacy Pediatrics, Rochester, NY 14618, USA.
authors.forename: Janet R
authors.initials: JR
authors.lastname: Casey
authors.affiliation: Rochester General Hospital Research Institute, Rochester, NY 14621, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Pichichero
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D002353:Carrier State / Q000276:immunology / Q000382:microbiology*; D002675:Child, Preschool; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D001936:Moraxella catarrhalis / Q000276:immunology*; D045828:Moraxellaceae Infections / Q000276:immunology* / Q000382:microbiology; D009305:Nasopharynx / Q000382:microbiology; D010033:Otitis Media / Q000276:immunology / Q000382:microbiology*; D011446:Prospective Studies
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G
keywords: Acute otitis media; Antigen; Carriage; Immunogenicity; Nasopharyngeal colonization; Natural immunization; Recombinant proteins; Vaccine