title: Phosphatidylserine Outer Layer Translocation Is Implicated in IL-10 Secretion by Human Regulatory B Cells.
abstract: B cells can have a regulatory role, mainly mediated by interleukin 10 (IL-10). IL-10 producing B cells (B10 cells) cells remain to be better characterized. Annexin V binds phosphatidylserine (PS), which is externalized during apoptosis. Previous works suggested that B10 cells are apoptotic cells since they bind Annexin V. Others showed that Annexin V binding could also be expressed on viable B cells. We aimed to explore if PS exposure can be a marker of B10 cells and if PS exposure has a functional role on B cell IL-10 production in healthy subjects. We found that B10 cells were significantly more often Annexin V+ than IL-10 non-producing B cells. After CpG activation, Annexin V+ B cells differentiated more often into B10 cells than Annexin Vneg B cells. Cell death and early apoptosis were similar between Annexin V+ and Annexin Vneg B cells. PS blockage, using biotinylated AnV and glyburide, decreased B10 cell differentiation. This study showed that B10 cells have an increased PS exposure independently of any apoptotic state. B cells exposing PS differentiate more into B10 cells whereas PS blockage inhibits B10 cells generation. These results strongly suggest a link between PS exposure and B10 cells.
authors.affiliation: Department of Rheumatology, University Hospital Center of Montpellier, Montpellier, France.|TNF-alpha family laboratory, UMR5535, IGMM, CNRS, Montpellier, France.
authors.forename: Rachel
authors.initials: R
authors.lastname: Audo
authors.affiliation: Department of Rheumatology, University Hospital Center of Montpellier, Montpellier, France.|TNF-alpha family laboratory, UMR5535, IGMM, CNRS, Montpellier, France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Hua
authors.affiliation: TNF-alpha family laboratory, UMR5535, IGMM, CNRS, Montpellier, France.
authors.forename: Michael
authors.initials: M
authors.lastname: Hahne
authors.affiliation: Department of Rheumatology, University Hospital Center of Montpellier, Montpellier, France.|TNF-alpha family laboratory, UMR5535, IGMM, CNRS, Montpellier, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Combe
authors.affiliation: Department of Rheumatology, University Hospital Center of Montpellier, Montpellier, France.|TNF-alpha family laboratory, UMR5535, IGMM, CNRS, Montpellier, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Morel
authors.affiliation: Department of Rheumatology, University Hospital Center of Montpellier, Montpellier, France.|TNF-alpha family laboratory, UMR5535, IGMM, CNRS, Montpellier, France.
authors.forename: Claire I
authors.initials: CI
authors.lastname: Daien
mesh_terms: D017209:Apoptosis; D060151:B-Lymphocytes, Regulatory / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D016753:Interleukin-10 / Q000378:metabolism*; D010718:Phosphatidylserines / Q000378:metabolism*
chemical_list: D010718:Phosphatidylserines; D016753:Interleukin-10