Blimp-1 regulates B and T cell terminal differentiation
Blimp-1 is a crucial regulator of plasma cell development. We have produced a Blimp-1-GFP reporter allele that facilitates the simple and efficient characterisation of all plasma cells in the mouse. Plasma cells are extremely rare (0.2% of bone marrow) but the exact coincidence of high Blimp-1 expression and antibody secretion enables us to isolate pure populations of these cells. These studies revealed that increasing Blimp-1-GFP levels exactly correlating with the maturation of plasmablasts into long-lived plasma cells. The Blimp-1-GFP mouse provides us with an excellent tool to further characterize the transcription factor network that controls plasma cell differentiation.
Blimp-1 is also a crucial regulator of T cell differentiation and homeostasis. Blimp-1 is expressed in a subset of CD4+ and CD8+ T cells that have characteristics of being effector/memory cells. Mice lacking Blimp-1 develop a lethal multi-organ inflammatory disease caused by an accumulation of effector and memory T cells. These data suggest a conserved function of Blimp-1 in regulating the final stages of both B and T cell differentiation. Using viral infection models, we have recently found that a major function of Blimp-1 in the CD8+ T cell lineage is to promote the differentiation of short-lived killer T cells that are important for the anti-viral response. The molecular mechanisms by which Blimp-1 regulates T cell differentiation is currently under investigation.
