CD4 + T cells of the indicated genotypes or in the presence of the indicated inhibitors were cultured for 1 h in the presence or absence of plate-bound anti-CD3 and anti-CD28 antibodies. In some cultures, tonicities were altered by modulating concentrations of NaCl and L-glucose. Graphs show the percentage of cells that were p-ERK high as determined by flow cytometry, gating as in Supplementary Fig. 10a, b ( n = 5).
