PR001355 (Project)

Description:The function of mitochondrial respiration during B cell fate decisions and differentiation 55 remained equivocal. This study reveals that selection for mitochondrial fitness occurs during B 56 cell activation and is essential for subsequent plasma cell differentiation. By expressing a 57 mutated mitochondrial helicase in transitional B cells, we depleted mitochondrial DNA during 58 B cell maturation, resulting in reduced oxidative phosphorylation. Although no changes in 59 follicular B cell development were evident, germinal centers, class switch recombination to 60 IgG, plasma cell maturation and humoral immunity were diminished. Defective oxidative 61 phosphorylation led to aberrant flux of the tricarboxylic acid cycle and lowered the amount of 62 saturated phosphatidic acid. Consequently, mTOR activity and BLIMP1 induction were 63 curtailed whereas HIF1? _and glycolysis were amplified. Exogenous phosphatidic acid 64 increased mTOR activity in activated B cells. Hence, mitochondrial function is required and 65 selected for in activated B cells for the successful generation of functional plasma cells.