title: Impaired serotype-specific immune function following pneumococcal vaccination in infants with prior carriage.
abstract: The impact of prior nasopharyngeal carriage on serotype-specific IgG responses following immunization with pneumococcal conjugate vaccines (PCV) has recently been described. This report extends these findings to describe the attenuation of functional immune responses following 23-valent pneumococcal polysaccharide vaccination (PPS). We report the attenuation of immune responses following booster with the 23-valent pneumococcal polysaccharide vaccination (PPS) in infants with prior nasopharyngeal carriage of Streptococcus pneumoniae. Fijian infants who were part of a phase II randomized, controlled trial of reduced dose PCV7 schedules were the basis of this study. Pneumococcal carriage was determined at 6, 9 and 12 months of age, prior to PPS immunization. Serum samples collected at 18 weeks (post-PCV7), 12 months (pre-PPS), 12.5 months and 17 months (post-PPS) of age were assessed for serotype-specific IgG and opsonophagocytic responses. The most frequently carried serotypes were 6B (N=11), 19F (N=14) and 23F (N=23). Significantly lower serotype-specific IgG for 19F, 23F but not 6B post-PPS were detected in infants with homologous serotype carriage prior to PPS compared with non-carriers (N=230). However, OPA levels for 6B and 23F were lower in infants that carried these serotypes. Pneumococcal carriage with 19F or 23F at any time prior to PPS immunization in infants at 12 months of age who were previously primed with PCV resulted in serotype-specific hyporesponsiveness that persisted until 17 months of age. These results may have implications for the timing of infant vaccine schedules, particularly in high disease burden settings.
authors.affiliation: Pneumococcal Research Group, Australia; Allergy and Immune Disorders Group, Murdoch Childrens Research Institute, Australia. Electronic address: paul.licciardi@mcri.edu.au.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Licciardi
authors.affiliation: Pneumococcal Research Group, Australia; Centre for International Child Health, Department of Paediatrics, The University of Melbourne, Melbourne, Australia.
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Russell
authors.affiliation: Pneumococcal Research Group, Australia; Allergy and Immune Disorders Group, Murdoch Childrens Research Institute, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Balloch
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, USA; Department of Microbiology, University of Alabama at Birmingham, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Burton
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, USA; Department of Microbiology, University of Alabama at Birmingham, USA.
authors.forename: Moon H
authors.initials: MH
authors.lastname: Nahm
authors.affiliation: Westmead Millennium Institute for Medical Research, University of Sydney, Australia.
authors.forename: Gwendolyn
authors.initials: G
authors.lastname: Gilbert
authors.affiliation: Pneumococcal Research Group, Australia; The Royal Children's Hospital, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia.
authors.forename: Mimi L K
authors.initials: ML
authors.lastname: Tang
authors.affiliation: Pneumococcal Research Group, Australia; Menzies School of Health Research, Darwin, Australia; London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Edward K
authors.initials: EK
authors.lastname: Mulholland
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood; D000918:Antibody Specificity; D002353:Carrier State / Q000276:immunology*; D005367:Fiji; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D009305:Nasopharynx / Q000382:microbiology; D010587:Phagocytosis; D011008:Pneumococcal Infections / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage*; D012703:Serotyping; D016037:Single-Blind Method; D013296:Streptococcus pneumoniae / Q000145:classification; D013997:Time Factors
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D022242:Pneumococcal Vaccines
keywords: Carriage; Hyporesponsiveness; Opsonophagocytosis; PPS; Pneumococcal