CD8+ T cell reactivity to HLA-A2-restricted peptides in ELISPOT IFN-γ assays. (A) CD8+ T cells from NW731, a patient with NY-ESO-1-positive melanoma and NY-ESO-1 antibody. (B) CD8+ T cells from NW681, a patient with NY-ESO-1-positive melanoma and no NY-ESO-1 antibody. CD8+ T cells were presensitized with NY-ESO-1 p157–165, Melan-A/MART-1 p26–35, MAGE-3 p271–279, or flu matrix p58–66 and tested against T2 cells pulsed with the peptide panel shown at the bottom of the figure (including NY-ESO-1 p157–167). Effector-to-target cell ratios in these assays were 1:1 (solid bars) and 0.2:1 (hatched bars).