title: Comparison of anti-pneumococcal antibodies in cord blood from Australian indigenous and Gambian neonates and the implications for otitis media.
abstract: BACKGROUND
  Australian indigenous infants experience the highest incidence of chronic suppurative and acute otitis media in the world with many babies developing disease in the early postnatal period. Streptococcus pneumoniae is the major cause of otitis media in this population. Infants are protected against bacterial disease in the first months of life by passive transfer of maternal antibody across the placenta during the late stages of gestation. We hypothesized that reduced passive immunity may contribute to increased disease risk in this population. We compared the concentrations and function of serotype-specific IgG in cord serum from Australian indigenous neonates and Gambian neonates, the latter experiences a similar socioeconomic status to Australian indigenous neonates.
  
  
  METHODS
  Serotype-specific IgG, IgG1 and IgG2 were measured using a modified 3rd generation enzyme linked immunosorbent assay based on World Health Organization recommendations. Antibody avidity was measured using a modified sodium thiocyanate elution method.
  
  
  RESULTS
  Australian indigenous neonates had significantly increased levels of serotype-specific IgG compared with Gambian populations for 6 of 12 serotypes (P < 0.02). There was no significant difference in antibody function, as measured by antibody avidity, between the 2 groups.
  
  
  CONCLUSIONS
  An increased risk for otitis media in Australian indigenous neonates is not primarily determined by specific antibody titers against pneumococcal bacteria. Further investigation into the possible roles of the innate immune response and Eustachian tube dysfunction in the development of chronic otitis media amongst Australian indigenous infants is warranted.
authors.affiliation: From the *Murdoch Childrens Research Institute, Melbourne; †Menzies School of Health Research, Royal Darwin Hospital, Darwin, Australia; ‡London School of Hygiene and Tropical Medicine, University of London, London, United Kingdom; §Royal Children's Hospital, Melbourne; and ¶Department of Paediatrics, The University of Melbourne, Parkville, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Balloch
authors.forename: Paul V
authors.initials: PV
authors.lastname: Licciardi
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Kemp
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Leach
authors.forename: E Kim
authors.initials: EK
authors.lastname: Mulholland
authors.forename: Mimi Lk
authors.initials: ML
authors.lastname: Tang
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D000915:Antibody Affinity; D001315:Australia / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005714:Gambia / Q000453:epidemiology; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000097:blood*; D007231:Infant, Newborn; D010033:Otitis Media / Q000097:blood / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology; D011008:Pneumococcal Infections / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000382:microbiology; D011247:Pregnancy; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D007074:Immunoglobulin G