Stearoyl-CoA desaturase mediated monounsaturated fatty acid availability supports humoral immunity

Immune cells can metabolize fatty acids (FAs) to generate energy. The source of different fatty acid species, and their impacts on humoral immunity remains poorly understood. Here we report that proliferating B cells require increased amount of monounsaturated fatty acids (MUFA) to maintain mitochondrial metabolism and mTOR activity, and to prevent excessive autophagy and endoplasmic reticular (ER) stress. Furthermore, B cell extrinsic Stearoyl-Coa desaturase (SCD) activity generates endogenous MUFA to support early B cell development and germinal center (GC) formation in vivo during immunization and influenza infection. Thus, SCD-mediated MUFA production is critical for humoral immunity. Overall design: Splenic follicular B cells were flow sorted.They were activated by LPS/IL-4 for 72 hours. Total RNA was extracted using Rneasy micro kit (Qiagen).