Fig. 4.

Exogenous lipids rescue Treg but not Teff differentiation in the absence of ERRα. (A and B) Teff (Th1, Th2, Th17) and Treg cells were generated in vitro from WT CD4⁺ T cells in the presence or absence of XCT790 (XCT) and in the presence or absence of fatty acid (FA) on day 0. (A) After 5 d, T-cell lineages were assayed by intracellular flow cytometry for cytokine production. (B) CFSE-labeled CD4⁺ T cells were differentiated in the presence or absence of XCT790 or FA and assessed by flow cytometry 3 d poststimulation. (C) On day 5 after T-cell lineages were established, XCT790 was added to cultures, and cytokine production was assessed after an additional 48 h by intracellular flow cytometry for cytokine production. Results are representative of three independent experiments.