NRP1 and melanoma: To investigate the impact of Nrp-1 engagement with its ligand on CD8+ TIL functions in vivo, we used C57BL/6 mice engrafted with B16F10 melanoma cells, which express the Nrp-1 soluble ligand Sema-3B, as shown by qRT-PCR analyses (Supplementary Fig. 4a) and confirmed by western blot (Fig. 3a).