title: Role of tonsillar IgD+CD27+ memory B cells in humoral immunity against pneumococcal infection.
abstract: IgD+CD27+ memory B cells are a major compartment of circulating memory B cells. However, the characteristics of these cells in the tonsils have been unclear. In this study, IgD+CD27+ memory B cells residing in the tonsillar marginal zone were found to exhibit similar characteristics as IgD+CD27+ memory B cells in the periphery, namely large morphology, expression of surface molecules, and hypermutated Ig variable region genes. Furthermore, these IgD+CD27+ memory B cells predominantly produced IgM, including IgM specific against pneumococcal polysaccharides. Taken together, these results provide convincing evidence that tonsillar IgD+CD27+ memory B cells impart protective humoral immunity against pneumococcal infection by producing high-affinity IgM.
authors.affiliation: Department of Infectious Immunology and Pediatrics, Graduate School of Medicine, Shinshu University, Matsumoto, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takizawa
authors.forename: Kazuo
authors.initials: K
authors.lastname: Sugane
authors.forename: Kazunaga
authors.initials: K
authors.lastname: Agematsu
mesh_terms: D000293:Adolescent; D000328:Adult; D000915:Antibody Affinity / Q000276:immunology; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007072:Immunoglobulin D / Q000096:biosynthesis / Q000276:immunology*; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000276:immunology; D007156:Immunologic Memory; D008297:Male; D008875:Middle Aged; D014066:Palatine Tonsil / Q000276:immunology* / Q000378:metabolism; D011008:Pneumococcal Infections / Q000276:immunology* / Q000378:metabolism; D027041:Somatic Hypermutation, Immunoglobulin / Q000276:immunology; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000276:immunology*
chemical_list: D007072:Immunoglobulin D; D007075:Immunoglobulin M; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7