title: Antibody response to pneumococcal capsular polysaccharides in children with acute otitis media.
abstract: BACKGROUND
  To describe the antibody response to pneumococcal capsular polysaccharides in children <2 years of age with pneumococcal acute otitis media (AOM) caused by serotypes 6A, 6B, 11A, 14, 19F or 23F. These serotypes were commonly found in both nasopharyngeal carriage and AOM in children of the study population in Finland.
  
  
  METHODS
  Serum antibody concentrations to pneumococcal capsular polysaccharides of types 6B, 11A, 14, 19F and 23F were measured by enzyme immunoassay in acute and convalescent sera from children with AOM.
  
  
  RESULTS
  Responses (at least 2-fold increase of antibody concentration) were relatively infrequent and varied with both the age of the child and the serotype of the Streptococcus pneumoniae isolated from the middle ear fluid. Children older than 12 months were more likely to have antibody responses than were younger children. Responses were seen only infrequently to types 6A, 6B or 19F (1 of 14, 1 of 9 and 2 of 25, respectively), more often to types 11A and 14 (2 of 8 and 3 of 8) and relatively frequently to type 23F (8 of 18). However, the convalescent antibody concentrations to type 23F were low and usually declined after the infection, whereas responders to 14 AOM had antibodies that persisted at a high concentration through the follow-up.
  
  
  CONCLUSIONS
  The results emphasize the differences between Streptococcus pneumoniae serotypes in their immunogenicity and quantitative and qualitative differences of antibodies produced after infection.
authors: Department of Vaccines, National Public Health Institute, Helsinki, Finland.
authors: Anu
authors: A
authors: Soininen
authors: Mika
authors: M
authors: Lahdenkari
authors: Terhi
authors: T
authors: Kilpi
authors: Pirjo Helena
authors: PH
authors: Mäkelä
authors: Helena
authors: H
authors: Käyhty
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D016667:Bacterial Capsules / Q000276:immunology*; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007223:Infant; D008297:Male; D010033:Otitis Media / Q000276:immunology* / Q000382:microbiology*; D011008:Pneumococcal Infections / Q000276:immunology; D012307:Risk Factors; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial