Notch determines B cell fate

The spleen converts immature transitional B cells from bone marrow into follicular B cells and marginal zone B (MZB) cells, but the molecular mechanisms involved in inducing cell differentiation remain unclear. In April 22 online Nature Immunology, Kenji Tanigaki and colleagues from Kyoto University, Japan, show that the Notch–RBP-J signaling pathway is involved in cell fate determination of MZB (Nat Immunol 2002, DOI: 10.1038/ni793).

Tanigaki et al. generated mice that selectively lacked B cell RBP-J expression and observed that the absence of RBP-J led to the loss of MZB cells with a concomitant increase in follicular B cells, but B cells in the peritoneal cavity were unaffected. In addition, mice with RBP-J–deficient B cells showed no obvious changes in immunoglobulin production, but exhibited increased mortality rates after blood-borne bacterial infection.

These results show new molecular mechanisms of B cell differentiation, and "indicates that MZB cells play pivotal roles in the ...