GIMAP1 Is Essential for the Survival of Naive and Activated B Cells In Vivo.

An effective immune system depends upon regulation of lymphocyte function and homeostasis. In recent years, members of the GTPases of the immunity associated protein (GIMAP) family were proposed to regulate T cell homeostasis. In contrast, little is known about their function and mode of action in B cells. We used a combination of transgenic mice and in vivo and in vitro techniques to conditionally and electively ablate GIMAP1 in resting and activated peripheral B cells. Our data suggest that GIMAP1 is absolutely essential for the survival of peripheral B cells, irrespective of their activation state. Together with recent data showing increased expression of GIMAP1 in B cell lymphomas, our work points to the possible potential of GIMAP1 as a target for manipulation in a variety of B cell-mediated diseases.