U.R., B.S., and J.A.L. AKT plays a central role in upregulating glycolysis via induction of lactate dehydrogenase expression, but has no impact on glucose uptake of T cells. Furthermore, under apoptosis inducing conditions, T cells are not able to upregulate glycolysis and induce lactate production. In addition maintaining high glycolytic rates strongly depends on IL-2 production. Electronic supplementary material The online version of this article (doi:10.1186/s12860-016-0104-x) contains supplementary material, which is available to authorized users. strong class=”kwd-title” Keywords: Entecavir hydrate T-cell activation, Aerobic glycolysis, AKT/PKB, Lactate Background T cells play a central role in the Entecavir hydrate immune system and are crucial for the adoptive immune response. Activation of T cells by specific antigens leads to proliferation, differentiation into effector cells, and cytokine production. A variety of stimuli, including soluble or immobilized antibodies (Abs) that recognize the T cell receptor (TCR), peptide-loaded APCs, or MHC-I tetramers carrying high- or low-affinity peptides, have been used to study T cell responses. It was previously shown that different stimuli lead to either proliferation or apoptosis of thymocytes  and mature T cells . However, it is poorly understood how triggering of the same receptor with ligands of different affinity can induce these different outcomes. Since it is known that thymocytes which cannot fulfill their energy demands undergo apoptosis  we hypothesized that changes in the metabolic profiles in activated T cells might contribute to cell fate specification. Stimulation of T cells leads to a change from a quiescent resting state into an activated state, which is characterized by an extensive cell growth, proliferation, and the production of effector proteins, such as cytokines. In the resting state, T lymphocytes maintain their basal energy demands primarily through a mixed usage of glucose and glutamine . However, to meet the increased energy demands following activation, glucose metabolism increases as a source of energy and providing precursor molecules for cellular biosynthesis . Unlike hepatocytes and myocytes, lymphocytes do not have large internal glycogen stores. This makes them highly dependent on extracellular glucose. Glucose uptake in T cells is mediated by the glucose-transporter 1 (GLUT1). It was previously shown that upregulation of GLUT1 expression depends on co-stimulation via CD28 [5, 6]. Co-stimulation is also responsible for the activation of PI3K/AKT, which is thought to be involved in the expression of GLUT1 at the cell surface . However it was shown recently that AKT does not appear to be required for the upregulation of GLUTI and for the increase in glucose uptake Entecavir hydrate upon T cell stimulation . Another important regulator of cellular metabolism is the adenosine-monophosphate kinase (AMPK), which promotes ATP conservation and production through the upregulation of glycolysis, fatty acid oxidation, and the inhibition of ATP-consuming pathways such as protein synthesis, fatty acid synthesis, gluconeogenesis, and glycogen synthesis. AMPK can be activated by an increase in the AMP:ATP ratio followed by phosphorylation through LKB1, a serine/threonine kinase [9C11]. In addition it is known that triggering of the TCR activates AMPK in an AMP-independent, but Ca2+-calmodulin-dependent kinase kinase 2 (CAMKK2)-dependent manner, which was shown to activate AMPK independent of AMP levels [12, 13]. We demonstrate Entecavir hydrate here that stimulation of murine CD8+ T cells with MHC-I tetramers carrying the high affinity OVA-peptide SIINFEKL leads to the transient activation of AMPK followed by an increase in the glycolytic rate and production of lactate, to counter the increased demand for ATP after activation. Furthermore, we show that the inhibition of lactate production leads to a decreased proliferation. Additionally we confirmed that AKT is required for the glycolytic change in CD8+ T cells whereas mTOR is Rabbit polyclonal to AQP9 dispensable. Investigation of later time points revealed a connection between CTLA4 upregulation and downregulation of IL2 production accompanied by subsequent downregulation of lactate production. Results Antibody stimulation induces ATP depletion, whereas tetramers do not In our.