PMEL and melanoma: To this end, gp100-reactive T cell receptor (TCR) transgenic CD8+ T cells (Pmel T cells) were activated with their cognate antigen for 3 days and adoptively cotransferred (at a 1:1 ratio) with either WT or CD38−/− iTregs, which were CellTrace Violet (CTV)–labeled, into B16-F10 melanoma-bearing mice with tumors established subcutaneously for 10 days.