title: Avidity maturation following vaccination with a meningococcal recombinant hexavalent PorA OMV vaccine in UK infants.
abstract: To date, there are no data assessing the utility of avidity indices as a surrogate marker for the induction of immunological memory following meningococcal serogroup B outer membrane vesicle (OMV) vaccination. We studied infants who had been immunized with three doses of a recombinant hexavalent PorA OMV vaccine at ages 2-4 months, together with a fourth dose at age 12-18 months. A control group had received a single dose of the same vaccine at age 12-18 months. As previously reported, serum bactericidal antibody (SBA) titres increased after each of the first three doses, with a significant increase observed from 6 months post third dose to 1 month post fourth dose. The geometric mean avidity indices (GMAI), against strain H44/76 OMVs, increased from 1 month post first dose to 1 month post third dose. Significant increases in GMAI were observed at 6 months post third dose and again following the fourth dose. At 32-42 months of age, though the SBA titres had returned to post first dose levels, the GMAI remained elevated. No increase in avidity was observed in the control group. Antibody avidity indices are useful laboratory markers for the priming of immunological memory following vaccination with meningococcal serogroup B OMV vaccines.
authors.affiliation: Meningococcal Reference Unit, Manchester Public Health Laboratory, Withington Hospital, Nell Lane, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Longworth
authors.forename: Ray
authors.initials: R
authors.lastname: Borrow
authors.forename: David
authors.initials: D
authors.lastname: Goldblatt
authors.forename: Paul
authors.initials: P
authors.lastname: Balmer
authors.forename: Maureen
authors.initials: M
authors.lastname: Dawson
authors.forename: Nick
authors.initials: N
authors.lastname: Andrews
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Miller
authors.forename: Keith
authors.initials: K
authors.lastname: Cartwright
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology; D000915:Antibody Affinity; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007223:Infant; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D018272:Porins / Q000008:administration & dosage* / Q000276:immunology; D006113:United Kingdom; D014614:Vaccines, Synthetic / Q000008:administration & dosage* / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D022401:Meningococcal Vaccines; D018272:Porins; D014614:Vaccines, Synthetic; C057699:porin protein, Neisseria