A guide to B cell metabolism.

The metabolism of immune cells must adapt dynamically to support their diverse functions. B cells, which are the key cellular mediators of humoral immunity, undergo extensive metabolic changes throughout their development and function, starting from their commitment to the B cell lineage in the bone marrow. In the periphery, further rounds of metabolic adaptation in B cells are driven by temporally regulated changes in signalling cues, energetic demands and nutrient availability within specialized tissue niches. Although they have historically been less well studied than other immune cell types, emerging evidence shows that B cells deploy mechanistically distinct metabolic strategies that are tightly linked to their effector identity. Recognizing B cell metabolism as its own biological entity is, therefore, crucial to the study of humoral immune responses. In this Review, we examine the metabolic pathways that regulate B cell homeostasis, their integration with cell signalling networks, and their adaptation to the metabolic environment across spatial and temporal scales. We further discuss how aberrations in these pathways can contribute to B cell-driven malignancies, autoimmunity, inborn errors of immunity, and B cell-tropic infections. We position B cell metabolism as a rapidly expanding frontier within immunometabolism in both health and disease.