title: TLR9 Ligand (CpG Oligodeoxynucleotide) Induces CLL B-Cells to Differentiate into CD20(+) Antibody-Secreting Cells.
abstract: B-cell chronic lymphocytic leukemia (CLL) is the most frequent adult leukemia in the Western world. It is a heterogeneous disease characterized by clonal proliferation and the accumulation of CD5(+) mature B lymphocytes. However, the normal counterpart from which the latter cells arise has not yet been identified. CD27 expression and gene expression profiling data suggest that CLL cells are related to memory B-cells. In vitro, memory B-cells differentiate into plasma cells when stimulated with CpG oligodeoxynucleotide (CpG). The objective of the present study was therefore to investigate the ability of CpG, in the context of CD40 ligation, to induce the differentiation of CLL B-cells into antibody-secreting cells (ASCs). CD20(+)CD38(-) CLL B-cells were stimulated with a combination of CpG, CD40 ligand and cytokines (CpG/CD40L/c) in a two-step, 7-day culture system. We found that the CpG/CD40L/c culture system prompted CLL B-cells to differentiate into CD19(+)CD20(+)CD27(+)CD38(-)ASCs. These cells secreted large amounts of IgM and had the same shape as plasma cells. However, only IgMs secreted by ASCs that had differentiated from unmutated CLL B-cells were poly/autoreactive. Class-switch recombination (CSR) to IgG and IgA was detected in cells expressing the activation-induced cytidine deaminase gene (AICDA). Although these ASCs expressed high levels of the transcription factors PRDM1 (BLIMP1), IRF4, and XBP1s, they did not downregulate expression of PAX5. Our results suggest that CLL B-cells can differentiate into ASCs, undergo CSR and produce poly/autoreactive antibodies. Furthermore, our findings may be relevant for (i) identifying the normal counterpart of CLL B-cells and (ii) developing novel treatment strategies in CLL.
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France.
authors: Hussein
authors: H
authors: Ghamlouch
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France.
authors: Hakim
authors: H
authors: Ouled-Haddou
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France.
authors: Aude
authors: A
authors: Guyart
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France ; Service d'Hématologie Clinique et Thérapie Cellulaire, Department of Hematology, Centre Hospitalier Régional Universitaire d'Amiens , Amiens , France.
authors: Aline
authors: A
authors: Regnier
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France ; Laboratoire d'Oncobiologie Moléculaire, Department of Molecular Oncobiology, Centre Hospitalier Régional Universitaire d'Amiens , Amiens , France.
authors: Stéphanie
authors: S
authors: Trudel
authors: Service d'Hématologie Clinique et Thérapie Cellulaire, Department of Hematology, Centre Hospitalier Régional Universitaire d'Amiens , Amiens , France.
authors: Jean-François
authors: JF
authors: Claisse
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France.
authors: Vincent
authors: V
authors: Fuentes
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France ; Service d'Hématologie Clinique et Thérapie Cellulaire, Department of Hematology, Centre Hospitalier Régional Universitaire d'Amiens , Amiens , France.
authors: Bruno
authors: B
authors: Royer
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France ; Service d'Hématologie Clinique et Thérapie Cellulaire, Department of Hematology, Centre Hospitalier Régional Universitaire d'Amiens , Amiens , France.
authors: Jean-Pierre
authors: JP
authors: Marolleau
authors: EA4666, Department of Immunology, Université de Picardie Jules Verne , Amiens , France ; Laboratoire d'Oncobiologie Moléculaire, Department of Molecular Oncobiology, Centre Hospitalier Régional Universitaire d'Amiens , Amiens , France.
authors: Brigitte
authors: B
authors: Gubler
keywords: B-cell differentiation; CD20; CpG oligodeoxynucleotide; antibody-secreting cells; chronic lymphocytic leukemia; memory B cell; poly/autoreactive IgM