title: Comparison of a limiting dilution assay and ELISpot for detection of memory B-cells before and after immunisation with a protein-polysaccharide conjugate vaccine in children.
abstract: In the present study, the limiting dilution assay (LDA) and the ELISpot are compared in their ability to detect serogroup C meningococcal (MenC)-specific memory B-cells in peripheral blood of 12month old children, after 3-dose priming with serogroup C meningococcal conjugate vaccine (MenCV) in infancy. At 12 months of age, MenC-memory B-cells were detected by ELISpot in 61% of children and in 5% by LDA. In contrast, carrier-specific memory B-cells were measurable in 36% of children by LDA and 78% by ELISpot. One month after a booster dose of MenCV given at 12 months of age, MenC-specific memory B-cells were detected in 89% of children by ELISpot and 65% of children by LDA, while diphtheria toxoid-specific memory B-cells were detected in 88% of children by ELISpot and in 74% of children by LDA. Two statistical methods were applied to enumerate memory B-cells with the LDA assay; the Poisson method allowed determination of very low frequencies that could not be determined by the Reed and Muench method. These data are examples of alternative methods to assess long-term protection after protein-polysaccharide conjugate vaccines, through direct measurement of memory B-cells in peripheral blood shortly after immunisation.
authors.affiliation: University of Oxford, Centre for Clinical Vaccinology and Tropical Medicine, Oxford, United Kingdom. Geraldine.BlanchardRohner@paediatrics.ox.ac.uk
authors.forename: Geraldine
authors.initials: G
authors.lastname: Blanchard-Rohner
authors.forename: Grazia
authors.initials: G
authors.lastname: Galli
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Clutterbuck
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pollard
mesh_terms: D016175:B-Lymphocyte Subsets / Q000276:immunology*; D002469:Cell Separation; D004168:Diphtheria Toxoid / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007074:Immunoglobulin G / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology*; D007223:Infant; D018655:Lymphocyte Count; D022401:Meningococcal Vaccines / Q000276:immunology*; D011135:Polysaccharides, Bacterial / Q000276:immunology; D014611:Vaccination / Q000379:methods*
chemical_list: D004168:Diphtheria Toxoid; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; D011135:Polysaccharides, Bacterial; C410218:serogroup C meningococcal conjugate vaccine