In order to characterize how melanoma tumours influence the CD4+ CD25− T-cells, healthy donors’ pre-activated primary CD4+CD25− T-cells were co-cultured with human cutaneous melanoma cell lines, including DFB, A375, and SK-MEL-28 (V600E) and BE and SK-MEL-2 (V600 wt), for five days (Fig. 2a). Here, CD4 is linked to melanoma.