title: Evaluation of the induction of immune memory following infant immunisation with serogroup C Neisseria meningitidis conjugate vaccines--exploratory analyses within a randomised controlled trial.
abstract: OBJECTIVE
  We measured meningococcal serogroup C (MenC)-specific memory B-cell responses in infants by Enzyme-Linked Immunospot (ELISpot) following different MenC conjugate vaccine schedules to investigate the impact of priming on immune memory.
  
  
  METHODS
  Infants aged 2 months were randomised to receive 1 or 2 doses of MenC-CRM197 at 3 or 3 and 4 months, 1 dose of MenC-TT at 3 months, or no primary MenC doses. All children received a Haemophilus influenzae type b (Hib)-MenC booster at 12 months. Blood was drawn at 5, 12, 12 months +6 days and 13 months of age.
  
  
  RESULTS
  Results were available for 110, 103, 76 and 44 children from each group respectively. Following primary immunisations, and prior to the 12-month booster, there were no significant differences between 1- or 2-dose primed children in the number of MenC memory B-cells detected. One month following the booster, children primed with 1 dose MenC-TT had more memory B-cells than children primed with either 1-dose (p = 0.001) or 2-dose (p<0.0001) MenC-CRM197. There were no differences in MenC memory B-cells detected in children who received 1 or 2 doses of MenC-CRM197 in infancy and un-primed children.
  
  
  CONCLUSIONS
  MenC-specific memory B-cell production may be more dependent on the type of primary vaccine used than the number of doses administered. Although the mechanistic differences between MenC-CRM197 and MenC-TT priming are unclear, it is possible that structural differences, including the carrier proteins, may underlie differential interactions with B- and T-cell populations, and thus different effects on various memory B-cell subsets. A MenC-TT/Hib-MenC-TT combination for priming/boosting may offer an advantage in inducing more persistent antibody.
  
  
  BACKGROUND
  EU Clinical Trials Register 2009-016579-31 ClinicalTrials.gov NCT01129518.
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
authors.forename: Ameneh
authors.initials: A
authors.lastname: Khatami
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Clutterbuck
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
authors.forename: Amber J
authors.initials: AJ
authors.lastname: Thompson
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: McKenna
authors.affiliation: Malta Children's Vaccine Group, Mater Dei Hospital, Tal-Qroqq, Msida, Malta.
authors.forename: David
authors.initials: D
authors.lastname: Pace
authors.affiliation: Centre for Statistics in Medicine, University of Oxford, Oxford, United Kingdom.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Birks
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Snape
authors.affiliation: Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pollard
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology*; D005260:Female; D006801:Humans; D007156:Immunologic Memory; D007223:Infant; D008297:Male; D038542:Neisseria meningitidis, Serogroup C / Q000276:immunology*; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000276:immunology
chemical_list: D001428:Bacterial Vaccines; D018074:Vaccines, Conjugate