B Cells Polarize Pathogenic Inflammatory T Helper Subsets through ICOSL-Dependent Glycolysis

B cells constitute abundant cellular components in inflamed human tissues, but their role in pathogenesis of inflammatory T helper (Th) subsets is still unclear. Here, we demonstrate that B cells, particularly resting naïve B cells, have a previously unrecognized helper function that is involved in shaping the metabolic process and subsequent inflammatory differentiation of T-cell-receptor-primed Th cells. ICOS/ICOSL axis-mediated glucose incorporation and utilization were crucial for inflammatory Th subset induction by B cells, and activation of mTOR was critical for T cell glycolysis in this process. Consistently, upon encountering ICOSL+ B cells, activated effector memory Th cells from patients with rheumatoid arthritis or systemic lupus erythematosus spontaneously differentiated into inflammatory Th subsets. Immunotherapy using an anti-CD20 antibody that specifically depleted B cells in patients with rheumatoid arthritis efficiently abrogated the capabilities of memory Th cells to incorporate and utilize glucose, thereby impairing the pathogenic differentiation of inflammatory Th subsets. To examine the metabolic process of Th cells after interacting with autologous B cells, we applied RNA-sequencing to analyze their transcriptional profiles. Overall design: T cells, cultured in medium or with B cells for 7 days in the presence of CD3-cross-linking Abs, were sorted for RNA-sequencing.