title: Characterization of proposed human B-1 cells reveals pre-plasmablast phenotype.
abstract: Controversy has arisen about the nature of circulating human CD20(+)CD27(+)CD43(+)CD70(-)CD69(-) B cells. Although originally described as being the human counterpart of murine B-1 B cells, some studies have raised the possibility that these might instead be plasmablasts. In this article, we have further characterized the putative B-1 cells and compared them directly with memory B cells and plasmablasts for several functional characteristics. Spontaneous antibody production of different isotypes as well as the induced production of antigen-specific antibodies after vaccination with a T-cell-dependent antigen did not reveal differences between the putative B-1 cells and genuine CD20(-) plasmablasts. Gene expression profiling of different B-cell subsets positioned the phenotype of putative B-1 cells closer to CD20(-) plasmablasts than to memory B cells. Moreover, putative B-1 cells could be differentiated into CD20(-) plasmablasts and plasma cells in vitro, supporting a pre-plasmablast phenotype. In conclusion, characterization of the putative B-1 cells revealed a functional phenotype and a gene expression profile that corresponds to cells that differentiate into CD20(-) plasmablasts. Our data offer perspectives for the investigation of differentiation of B cells into antibody secreting cells.
authors.affiliation: PharmAbs, The Katholieke Universiteit Leuven Antibody Centre, Katholieke Universiteit Leuven, Leuven, Belgium.
authors.forename: Kris
authors.initials: K
authors.lastname: Covens
authors.forename: Bert
authors.initials: B
authors.lastname: Verbinnen
authors.forename: Nick
authors.initials: N
authors.lastname: Geukens
authors.forename: Isabelle
authors.initials: I
authors.lastname: Meyts
authors.forename: Frans
authors.initials: F
authors.lastname: Schuit
authors.forename: Leentje
authors.initials: L
authors.lastname: Van Lommel
authors.forename: Marc
authors.initials: M
authors.lastname: Jacquemin
authors.forename: Xavier
authors.initials: X
authors.lastname: Bossuyt
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D015415:Biomarkers / Q000032:analysis; D002454:Cell Differentiation; D002478:Cells, Cultured; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D006801:Humans; D007136:Immunoglobulins / Q000276:immunology*; D007156:Immunologic Memory / Q000276:immunology*; D016130:Immunophenotyping; D010641:Phenotype; D010950:Plasma Cells / Q000276:immunology*
chemical_list: D015415:Biomarkers; D007136:Immunoglobulins