title: Serum bactericidal activity and isotype distribution of antibodies in toddlers and schoolchildren after vaccination with RIVM hexavalent PorA vesicle vaccine.
abstract: A clinical phase II trial with the RIVM hexavalent OMV vaccine containing six different PorAs was carried out in toddlers (2-3 years) and schoolchildren (7-8 years) in The Netherlands. Children were vaccinated three times (0, 2, 8 months). Sera after two and three vaccinations were analysed for serum bactericidal activity (SBA) and isotype distribution in whole cell enzyme linked immunosorbent assay (ELISA). The SBA after vaccination against the six PorAs was significantly different. We investigated whether the age specific and PorA specific differences in SBA titers correlated with differences in PorA specific IgG isotype distribution. The SBA titers were higher in toddlers compared with schoolchildren. After vaccination, IgG1 antibodies dominated the response followed by IgG3 antibodies. IgG2 levels were low, whereas IgG4 was not detected. Irrespective of PorA, IgG total and isotype specific titers after two and three vaccinations were significantly higher in toddlers than in schoolchildren. A weak correlation was found between IgG total or IgG1 and SBA. Although the immunogenicity of the six PorAs is very different, the isotype distribution was similar for all six tested PorAs. We conclude that the RIVM hexavalent PorA vesicle vaccine induces bactericidal antibodies mainly of the IgG1 and IgG3 isotypes that are considered to be most important for protection against disease. The isotype distribution of the response is not age-dependent.
authors.affiliation: Department of Pediatrics, Sophia Children's Hospital/University Hospital, Rotterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: de Kleijn
authors.forename: L
authors.initials: L
authors.lastname: van Eijndhoven
authors.forename: C
authors.initials: C
authors.lastname: Vermont
authors.forename: B
authors.initials: B
authors.lastname: Kuipers
authors.forename: H
authors.initials: H
authors.lastname: van Dijken
authors.forename: H
authors.initials: H
authors.lastname: Rümke
authors.forename: R
authors.initials: R
authors.lastname: de Groot
authors.forename: L
authors.initials: L
authors.lastname: van Alphen
authors.forename: G
authors.initials: G
authors.lastname: van den Dobbelsteen
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D001770:Blood Bactericidal Activity; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000097:blood*; D022401:Meningococcal Vaccines / Q000276:immunology*; D018272:Porins / Q000276:immunology*; D014611:Vaccination
chemical_list: D000907:Antibodies, Bacterial; D007132:Immunoglobulin Isotypes; D022401:Meningococcal Vaccines; D018272:Porins; C057699:porin protein, Neisseria