Lactate modulates effector T cell functions.

(A) Relative mRNA expression levels of the cytokines interferon-gamma (Ifn-γ), Tnf-β, Il-4, Il-5, Il-13, and Il-17 and of the transcription factor Rorc as assessed by qRT-PCR in CD4⁺ subsets Th0, Th1, Th2, and Th17 treated with sodium lactate (10 mM) or left untreated. mRNA levels of each cytokine expressed by untreated Th0 cells were set to 1. (B) Intracellular staining of IL-17A and IFN-γ in activated CD4⁺ T cells treated with sodium lactate (10 mM) or left untreated. (C) Relative mRNA expression levels of Il-17 and Rorc in activated CD4⁺ T cells treated with sodium lactate alone or in combination with an anti-Slc5a12 antibody. mRNA levels of untreated T cells were set to 1. (D) Cell survival of allogeneic endothelial cells in the presence of CD8⁺ cytotoxic T cells and lactic acid (10 mM) or sodium lactate (10 mM) shown as kinetic (left panel) and 6 h time point (right panel). (A, C, D left panel) Data is representative of three independent experiments; the underlying numerical data and statistical analysis for each independent experiment can be found in the supporting file, S1 Data, Fig 4A, 4C, and 4D. (B, D right panel) n = 3. (A–D) Underlying numerical data and statistical analysis can be found in the supporting file, S1 Data, Fig 4A–4D. Values denote mean ± SD. *p < 0.05; **p < 0.01.