Met-Flow, a strategy for single-cell metabolic analysis highlights dynamic changes in immune subpopulations

Patricia Ahl et al. present Met-Flow, a flow cytometry-based approach for capturing the metabolic state of immune cells across multiple pathways. The authors apply Met-Flow to a central memory T cell subset, showing the importance of glucose restriction and metabolic reprogramming to T cell polarization and expansion. A complex interaction of anabolic and catabolic metabolism underpins the ability of leukocytes to mount an immune response. Their capacity to respond to changing environments by metabolic reprogramming is crucial to effector function. However, current methods lack the ability to interrogate this network of metabolic pathways at single-cell level within a heterogeneous population. We present Met-Flow, a flow cytometry-based method capturing the metabolic state of immune cells by targeting key proteins and rate-limiting enzymes across multiple pathways. We demonstrate the ability to simultaneously measure divergent metabolic profiles and dynamic remodeling in human peripheral blood mononuclear cells. Using Met-Flow, we discovered that glucose restriction and metabolic remodeling drive the expansion of an inflammatory central memory T cell subset. This method captures the complex metabolic state of any cell as it relates to phenotype and function, leading to a greater understanding of the role of metabolic heterogeneity in immune responses.