CD8A and melanoma: Human T cell receptor (TCR) CD8+ T cells targeting the cancer testis antigen NY-ESO-1 (NY-ESO-1 CTLs) were generated by transducing primary human CD8+ T cells with TCR-expressing retrovirus as previously described.23 Three human BRAFV600E melanoma cell lines that endogenously express NY-ESO-1 antigen (A375, SKMEL37, and MEL624) and, to minimize potentially confounding antigenic heterogeneity, three A375 subclones with different levels of stable NY-ESO-1 expression (A375-A, A375-B, and antigen-negative A375-C) were cocultured with NY-ESO-1 CTLs at varying CTL densities (Figure S1A–G).