title: Antibodies to serotype 9V exhibit novel serogroup cross-reactivity following infant pneumococcal immunization.
abstract: Cross-reactivity within the pneumococcal immune response was examined in this study. Significant cross-reactivity between serotypes 9V, 15B and 19A was identified in infant post-immunization serum that could not be effectively titrated during specific IgG measurements. Pre-absorption using serotype 9V inhibited this cross-reactivity and normalized titratability in the WHO ELISA for serotypes 15B and 19A. However, this did not affect functional avid IgG and was associated with fewer pneumococcal conjugate vaccine (PCV) doses, suggesting that cross-reactive antibodies were of low avidity. The results in this study have important implications for assessment of vaccine immunogenicity.
authors.affiliation: Pneumococcal Laboratory, Murdoch Children's Research Institute, Melbourne, Australia. paul.licciardi@mcri.edu.au
authors.forename: P V
authors.initials: PV
authors.lastname: Licciardi
authors.forename: A
authors.initials: A
authors.lastname: Balloch
authors.forename: F M
authors.initials: FM
authors.lastname: Russell
authors.forename: E K
authors.initials: EK
authors.lastname: Mulholland
authors.forename: M L K
authors.initials: ML
authors.lastname: Tang
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D000915:Antibody Affinity; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D005367:Fiji; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007223:Infant; D022242:Pneumococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D012703:Serotyping; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000069443:Heptavalent Pneumococcal Conjugate Vaccine; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate