C. Schleiss et al. (jan 2019)
Scientific reports 9 1 701
BCR-associated factors driving chronic lymphocytic leukemia cells proliferation ex vivo.
A chronic antigenic stimulation is believed to sustain the leukemogenic development of chronic lymphocytic leukemia (CLL) and most of lymphoproliferative malignancies developed from mature B cells. Reproducing a proliferative stimulation ex vivo is critical to decipher the mechanisms of leukemogenesis in these malignancies. However, functional studies of CLL cells remains limited since current ex vivo B cell receptor (BCR) stimulation protocols are not sufficient to induce the proliferation of these cells, pointing out the need of mandatory BCR co-factors in this process. Here, we investigated benefits of several BCR co-stimulatory molecules (IL-2, IL-4, IL-15, IL-21 and CD40 ligand) in multiple culture conditions. Our results demonstrated that BCR engagement (anti-IgM ligation) concomitant to CD40 ligand, IL-4 and IL-21 stimulation allowed CLL cells proliferation ex vivo. In addition, we established a proliferative advantage for ZAP70 positive CLL cells, associated to an increased phosphorylation of ZAP70/SYK and STAT6. Moreover, the use of a tri-dimensional matrix of methylcellulose and the addition of TLR9 agonists further increased this proliferative response. This ex vivo model of BCR stimulation with T-derived cytokines is a relevant and efficient model for functional studies of CLL as well as lymphoproliferative malignancies.
EasySep™ Direct Human Naïve B Cell Isolation Kit
RosetteSep™ Human B Cell Enrichment Cocktail
EasySep™ Human B Cell Isolation Kit
Eash KJ et al. (MAY 2009)
Blood 113 19 4711--9
CXCR4 is a key regulator of neutrophil release from the bone marrow under basal and stress granulopoiesis conditions.
The number of neutrophils in the blood is tightly regulated to ensure adequate protection against microbial pathogens while minimizing damage to host tissue. Neutrophil homeostasis in the blood is achieved through a balance of neutrophil production, release from the bone marrow, and clearance from the circulation. Accumulating evidence suggests that signaling by CXCL12, through its major receptor CXCR4, plays a key role in maintaining neutrophil homeostasis. Herein, we generated mice with a myeloid lineage-restricted deletion of CXCR4 to define the mechanisms by which CXCR4 signals regulate this process. We show that CXCR4 negatively regulates neutrophil release from the bone marrow in a cell-autonomous fashion. However, CXCR4 is dispensable for neutrophil clearance from the circulation. Neutrophil mobilization responses to granulocyte colony-stimulating factor (G-CSF), CXCL2, or Listeria monocytogenes infection are absent or impaired, suggesting that disruption of CXCR4 signaling may be a common step mediating neutrophil release. Collectively, these data suggest that CXCR4 signaling maintains neutrophil homeostasis in the blood under both basal and stress granulopoiesis conditions primarily by regulating neutrophil release from the bone marrow.