A 1G4‐CD8 control and THEMIS KD cells were stimulated with NY‐ESO‐1 pMHC tetramers and analysed for pY142‐CD3‐ζ phosphorylation by flow cytometry. Data shown are representative of three independent experiments.B Quantification of pY142‐CD3‐ζ responses of cells from (A). Data from three independent experiments were used in the analysis. Responses are expressed as percentage of the positive control sodium pervanadate. n = 3, means ± SEM are shown; two‐tailed unpaired Student's t‐test, **P 0.01. 