When OT-I CD8+ T cells from WT or Cd226−/− mice were co-cultured with OVA (SIINFEKL) peptide loaded B16F10 melanoma cells expressing or deficient in both PVR and PVRL2, Cd226−/− CD8+ T cells exhibited a reduced capacity to kill antigen-loaded melanoma cells in a PVR- and/or PVRL2-dependent manner as compared to WT CD8+ T cells (Figure 1B). Here, PVR is linked to melanoma.