E1KO 293T cells were transfected with ERAP1 allotype combinations from OPSCC patients together with H2-Kb and X-SHL8 minigenes representing 20 amino acids and assessed for generation of SHL8 by B3Z activation. OPSCC ERAP1 allotype identity from patients with TIL status are shown in panels (A) CD8/TILhigh, (B) CD8/TILmoderate, (C) CD8/TILLow, (D) CD8/TILhigh and CD8/TILmoderate, (E) CD8/TILhigh and CD8/TILlow and (F) CD8/TILmoderate and CD8/TILlow. The relative presentation of trimmed X-SHL8 was compared to that of the maximal response using SHL8, which does not require ERAP1 activity. Data pooled from four independent experimental repeats ±SEM.