title: CD9 is a novel marker for plasma cell precursors in human germinal centers.
abstract: The germinal center (GC) is the dynamic microenvironment where Ag-activated B cells rapidly expand and differentiate, generating plasma cells (PC) that produce high affinity antibodies. B cells within the GC have great heterogeneity, containing B cells at different stages of activation and differentiation. However, there are few surface markers that allow subsets of GC-B cells to be distinguished. In the present study, we show that GC-B cells in human tonsils contain two distinct populations regarding CD9 expression; CD9- and CD9+ cells. CD9+ GC-B cells are functionally more differentiated towards PC based upon the following evidence; (1) CD9+ cells express higher levels of PC transcription factor, Blimp-1 while lower levels of B cell transcription factors, Bcl-6 and Pax-5, compared to CD9- cells, (2) CD9+ cells differentiate into plasmablasts faster than CD9- cells in the presence of cytokines that generate PC, and (3) CD9 expression was induced in CD9- GC-B cells under PC generating condition and gradually increased in the course of PC differentiation. Taken together, our data suggest that CD9 is a novel marker for a human GC-B cell subset that is committed to PC lineage.
authors.affiliation: Laboratory of Cellular Immunology, Ochsner Clinic Foundation, New Orleans, LA, USA. syoon@ochsner.org
authors.forename: Sun-Ok
authors.initials: SO
authors.lastname: Yoon
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: In Yong
authors.initials: IY
authors.lastname: Lee
authors.forename: Nakia
authors.initials: N
authors.lastname: Spencer
authors.forename: Phuong
authors.initials: P
authors.lastname: Vo
authors.forename: Yong Sung
authors.initials: YS
authors.lastname: Choi
mesh_terms: D016175:B-Lymphocyte Subsets / Q000276:immunology*; D015415:Biomarkers / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D019070:Cell Lineage; D002478:Cells, Cultured; D018858:Germinal Center / Q000166:cytology / Q000276:immunology*; D006801:Humans; D014066:Palatine Tonsil / Q000166:cytology / Q000276:immunology; D010950:Plasma Cells / Q000276:immunology*; D060245:Tetraspanin 29 / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C554869:CD9 protein, human; D060245:Tetraspanin 29