Bioenergetic analysis of human peripheral blood mononuclear cells

Leukocytes respond rapidly to pathogenic and other insults with responses ranging from cytokine production through to migration and phagocytosis. These are bioenergetically expensive and increased glycolytic flux provides ATP rapidly to support these essential functions. However, much of this work is from animal studies. To better understand the relative role of glycolysis and oxidative phosphorylation in human leukocytes, especially their utility in a translational research setting, we undertook a study of human peripheral blood mononuclear cells (MNCs) bioenergetics. Glycolysis was essential during LPS-mediated IL-1β, IL-6, and TNFα production as 2-deoxy-D-glucose significantly decreased output of all three cytokines. After optimising cell numbers and the concentrations of all activators and inhibitors, oxidative phosphorylation and glycolysis profiles of fresh and cryopreserved/resuscitated MNCs were determined to explore the utility of MNCs for determining the bioenergetics health profile in multiple clinical settings. While the LPS-induced cytokine response did not differ significantly between fresh and resuscitated cells from the same donors, cryopreservation/resuscitation significantly affected some measures of oxidative phosphorylation mostly, but also glycolysis. Bioenergetics analysis of human MNCs provides a quick, effective means to measure the bioenergetics health index of many individuals but cryopreserved cells are not suitable for such an analysis. The translational utility of this approach was tested by comparing MNCs of pregnant and non-pregnant women to reveal increased bioenergetics health index with pregnancy but significantly reduced basal glycolysis and glycolytic capacity. More detailed analysis of discrete leukocyte populations would be required to understand the relative roles of glycolysis and oxidative phosphorylation during inflammation and other immune responses.