Stability and plasticity of wild‐type and Pax5‐deficient precursor B cells

Summary: In Pax5 ‐deficient mice, B cell development is blocked at the pre‐BI cell stage. Like wild‐type, Pax5 –/– pre‐BI cells can be grown long‐term in vitro in the presence of stromal cells and IL‐7. However, unlike their wild‐type in vitro ‐grown counterparts, Pax5 –/– pre‐BI cells possess an extraordinary developmental plasticity showing hematopoietic stem cell features such as multipotency and self renewing capacity. Here we review and discuss this in vitro and in vivo plasticity of Pax5 –/– pre‐BI cells.