title: The relationship between concentration of specific antibody at birth and subsequent response to primary immunization.
abstract: OBJECTIVE
  Trans-placentally acquired antibodies can protect infants from infection in the first months of life. However, high concentrations of antibody at birth may impact the infant's own immune response to primary immunization. We examine the relationship between concentration of specific antibody to Bordetella pertussis, Haemophilus influenzae type b (Hib), tetanus toxoid and pneumococcal antigens at birth and following primary immunization.
  
  
  METHODS
  Healthy mother-infant pairs were recruited from a UK maternity unit. Peripheral blood samples were obtained at birth and 4 weeks after primary immunization. Specific antibody concentrations were determined using enzyme-linked immunosorbent assays. Pertussis antibody concentrations >50 IU/ml, Tetanus antibody levels >0.1 IU/ml and Hib antibody levels >0.15 mg/l were regarded as protective.
  
  
  RESULTS
  Following primary immunization, 35/36 (97%) infants had specific antibody concentrations associated with protection against Hib, 32/36 (89%) against pertussis and 36/36 (100%) against tetanus. Concentrations of all specific antibodies were significantly higher than at birth (p<0.0001), except anti-tetanus toxoid, p=0.41. However, there was an inverse correlation between infant antibody concentration at birth and fold-increase in antibody concentration post-immunization for tetanus: rs -0.86 (95%CI -0.93 to -0.74), p<0.0001; pneumococcus: rs -0.82 (95% CI -0.91 to -0.67), p<0.0001; pertussis: rs -0.77 (95% CI -0.89 to -0.58), p<0.0001 and Hib: rs -0.66 (95%CI -0.82 to -0.42), p<0.0001. The highest concentrations of specific IgG at birth were associated with lower concentrations post-immunization for tetanus (p=0.009) and pneumococcus (p=0.03). This association was not observed for Hib (p=0.88) or pertussis (p=0.14).
  
  
  CONCLUSIONS
  Higher antibody concentration at birth appeared to inhibit the response to infant immunization for tetanus and pneumococcus; the effect was less marked for Hib and pertussis. However, the majority of infants achieved high antibody levels post-immunization. This supports maternal immunization, as high levels of maternally derived antibody at birth may not inhibit infants' immunization responses in a clinically relevant manner.
authors.affiliation: Academic Department of Paediatrics, Imperial College London, 2nd Floor Wright Fleming Building, Norfolk Place, London W2 1PG, UK(4). Electronic address: cjones@sgul.ac.uk.
authors.forename: Christine
authors.initials: C
authors.lastname: Jones
authors.affiliation: Vaccinology Theme, Medical Research Council Unit - The Gambia, PO Box 273, Banjul, Gambia(5). Electronic address: l.pollock@imperial.ac.uk.
authors.forename: Louisa
authors.initials: L
authors.lastname: Pollock
authors.affiliation: Academic Department of Paediatrics, Imperial College London, 2nd Floor Wright Fleming Building, Norfolk Place, London W2 1PG, UK(4). Electronic address: s.barnett@imperial.ac.uk.
authors.forename: Sara M
authors.initials: SM
authors.lastname: Barnett
authors.affiliation: Academic Department of Paediatrics, Imperial College London, 2nd Floor Wright Fleming Building, Norfolk Place, London W2 1PG, UK(4); Vaccinology Theme, Medical Research Council Unit - The Gambia, PO Box 273, Banjul, Gambia(5). Electronic address: a.battersby@imperial.ac.uk.
authors.forename: Anna
authors.initials: A
authors.lastname: Battersby
authors.affiliation: Academic Department of Paediatrics, Imperial College London, 2nd Floor Wright Fleming Building, Norfolk Place, London W2 1PG, UK(4); Vaccinology Theme, Medical Research Council Unit - The Gambia, PO Box 273, Banjul, Gambia(5). Electronic address: b.kampmann@imperial.ac.uk.
authors.forename: Beate
authors.initials: B
authors.lastname: Kampmann
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000276:immunology; D005260:Female; D006192:Haemophilus Infections / Q000276:immunology / Q000517:prevention & control; D018073:Haemophilus Vaccines / Q000276:immunology; D006801:Humans; D056724:Immunity, Humoral; D007112:Immunity, Maternally-Acquired; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011008:Pneumococcal Infections / Q000276:immunology / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000276:immunology; D013742:Tetanus / Q000276:immunology / Q000517:prevention & control; D013745:Tetanus Toxoid / Q000276:immunology; D014917:Whooping Cough / Q000276:immunology / Q000517:prevention & control
chemical_list: D000907:Antibodies, Bacterial; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D018073:Haemophilus Vaccines; D022242:Pneumococcal Vaccines; D013745:Tetanus Toxoid
keywords: Immune response; Infant; Vaccine