Cutting edge: Essential role of phospholipase C-gamma 2 in B cell development and function

Cross-linking of the B cell Ag receptor (BCR) induces the tyrosine phosphor ylation of multiple cellular substrates, including phospholipase C (PLC)-ga mma 2, which is involved in the activation of the phosphatidylinositol path way. To assess the importance of PLC-gamma 2 in murine lymphopoiesis, the P LC-gamma 2 gene was inducibly ablated by using IFN-regulated Cre recombinas e. Mice with a neonatally induced loss of PLC-gamma 2 function displayed re duced numbers of mature conventional B cells and peritoneal B1 cells and de fective responses in vitro to BCR stimulation and in vivo to immunization w ith thymus-independent type II Ags. In contrast, T cell development and TCR -mediated proliferation were normal. Taken together, PLC-gamma 2 is a criti cal component of BCR signaling pathways and is required to promote B cell d evelopment.