title: Reduced Number of Transitional and Naive B Cells in Addition to Decreased BAFF Levels in Response to the T Cell Independent Immunogen Pneumovax®23.
abstract: Protective immunity against T cell independent (TI) antigens such as Streptococcus pneumoniae is characterized by antibody production of B cells induced by the combined activation of T cell independent type 1 and type 2 antigens in the absence of direct T cell help. In mice, the main players in TI immune responses have been well defined as marginal zone (MZ) B cells and B-1 cells. However, the existence of human equivalents to these B cell subsets and the nature of the human B cell compartment involved in the immune reaction remain elusive. We therefore analyzed the effect of a TI antigen on the B cell compartment through immunization of healthy individuals with the pneumococcal polysaccharide (PnPS)-based vaccine Pneumovax®23, and subsequent characterization of B cell subpopulations. Our data demonstrates a transient decrease of transitional and naïve B cells, with a concomitant increase of IgA+ but not IgM+ or IgG+ memory B cells and a predominant generation of PnPS-specific IgA+ producing plasma cells. No alterations could be detected in T cells, or proposed human B-1 and MZ B cell equivalents. Consistent with the idea of a TI immune response, antigen-specific memory responses could not be observed. Finally, BAFF, which is supposed to drive class switching to IgA, was unexpectedly found to be decreased in serum in response to Pneumovax®23. Our results demonstrate that a characteristic TI response induced by Pneumovax®23 is associated with distinct phenotypical and functional changes within the B cell compartment. Those modulations occur in the absence of any modulations of T cells and without the development of a specific memory response.
authors.affiliation: Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany.
authors.forename: Alena
authors.initials: A
authors.lastname: Roth
authors.affiliation: Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Glaesener
authors.affiliation: Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Schütz
authors.affiliation: Pediatric Pneumology, Allergy and Neonatology, Hannover Medical School, Hannover, Germany.
authors.forename: Almut
authors.initials: A
authors.lastname: Meyer-Bahlburg
mesh_terms: D000328:Adult; D053264:B-Cell Activating Factor / Q000097:blood*; D001402:B-Lymphocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007114:Immunization; D007156:Immunologic Memory; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D055815:Young Adult
chemical_list: D053264:B-Cell Activating Factor; D022242:Pneumococcal Vaccines; C505719:TNFSF13B protein, human