HIF1α-Dependent Metabolic Signals Control the Differentiation of Follicular Helper T Cells

Follicular helper T (T(FH)) cells are critical for germinal center (GC) formation and are responsible for effective B cell-mediated immunity; metabolic signaling is an important regulatory mechanism for the differentiation of T(FH) cells. However, the precise roles of hypoxia inducible factor (HIF) 1α-dependent glycolysis and oxidative phosphorylation (OXPHOS) metabolic signaling remain unclear in T(FH) cell differentiation. Herein, we investigated the effects of glycolysis and OXPHOS on T(FH) cell differentiation and GC responses using a pharmacological approach in mice under a steady immune status or an activated immune status, which can be caused by foreign antigen stimulation and viral infection. GC and T(FH) cell responses are related to signals from glycolytic metabolism in mice of different ages. Foreign, specific antigen-induced GC, and T(FH) cell responses and metabolic signals are essential upon PR8 infection. Glycolysis and succinate-mediated OXPHOS are required for the GC response and T(FH) cell differentiation. Furthermore, HIF1α is responsible for glycolysis- and OXPHOS-induced alterations in the GC response and T(FH) cell differentiation under steady or activated conditions in vivo. Blocking glycolysis and upregulating OXPHOS signaling significantly recovered T(FH) cell differentiation upon PR8 infection and ameliorated inflammatory damage in mice. Thus, our data provide a comprehensive experimental basis for fully understanding the precise roles of HIF1α-mediated glycolysis and OXPHOS metabolic signaling in regulating the GC response and T(FH) cell differentiation during stable physiological conditions or an antiviral immune response.