title: Serum antibody response to five Streptococcus pneumoniae proteins during acute otitis media in otitis-prone and non-otitis-prone children.
abstract: BACKGROUND
  Streptococcus pneumoniae (Spn) is one of the common bacteria responsible for episodic acute otitis media (AOM; non-otitis-prone), recurrent AOM (otitis-prone), and AOM treatment failure (AOMTF) in children.
  
  
  OBJECTIVE
  From a population of 268 children, we sought to compare the serum IgG antibody titers of 5 different Spn proteins (PhtD, LytB, PcpA, PhtE, and Ply) that are vaccine candidates in children with episodic AOM (n = 34), who were otitis prone (n = 35) and who had AOMTF (n = 25) caused by Spn.
  
  
  METHODS
  Antibody was quantitated by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  At their AOM visit, anti-PhtD, -LytB, -PhtE, and -Ply IgG antibody titers in otitis-prone children were significantly lower compared with non-otitis-prone children (P < 0.05) and children with AOMTF (P < 0.05). On comparing acute to convalescent geometric mean IgG antibody titers after AOM against the 5 proteins we found that otitis-prone, AOMTF, and non-otitis-prone children had no significant change in titers (except for PhtE in children with AOMTF), but detailed analysis showed that about one-third of the children in each cohort had a 2-fold rise in antibody to the studied antigens. Although non-otitis-prone children had significant increases (P < 0.001) between 6 and 24 months of age in anti-PhtD, PcpA, PhtE, and Ply IgG antibody titers as a consequence of nasopharyngeal colonization and AOM, otitis-prone children either failed to show rises or the rises were significantly less than the non-otitis-prone children.
  
  
  CONCLUSIONS
  Otitis-prone and AOMTF children mount less of an IgG serum antibody response as compared with non-otitis-prone children to Spn proteins after AOM and nasopharyngeal colonization.
authors.affiliation: Rochester General Hospital Research Institute, Center for Infectious Diseases and Immunology, Rochester, NY 14621, USA.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Kaur
authors.forename: Janet R
authors.initials: JR
authors.lastname: Casey
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; D002675:Child, Preschool; D004198:Disease Susceptibility / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D010033:Otitis Media / Q000276:immunology* / Q000382:microbiology; D011008:Pneumococcal Infections / Q000276:immunology* / Q000382:microbiology; D011446:Prospective Studies; D044967:Serum / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007074:Immunoglobulin G