Negatively Regulates their Cytoskeletal Rearrangement and Migration Expression of the Chemokine Receptor CCR2 on Immature B Cells

Immature B cells are targeted to specific areas in the spleen, where a fraction of these cells receive signals that induce them to mature and participate in the immune response. In this study, we show that the C-C chemokine receptor 2 (CCR2) is transcribed in immature B cells, while its message is dramatically down regulated at the mature stage. CCR2 deficient cells exhibit upregulation of chemokine-induced actin polymerization, migration, and homing to the lymph nodes of immature B cells. In addition, we demonstrate that control of homing by CCR2 is mediated by its ligand, CCL2/JE, which is secreted by B cells and downregulates the SDF-1 signaling cascade. Thus, this study describes an additional, previously uncharacterized, role for CCR2 and its ligand as negative regulators of the homing of immature B cells. only. For personal use at PENN STATE UNIVERSITY on February 23, 2013. bloodjournal.hematologylibrary.org From