IDO1 and neoplasm: Zhang et al. [199] created a nanovesicle (NV) from the membrane of transfected HEK 293 T cells to load the following components –PD-L1 receptor tagged with DsRed protein, dendritic cells (DC) and 1-methyl tryptophan, an inhibitor of indolamine 2,3-dioxygenase (IDO), which is an immunosuppressive molecule overexpressed by tumour.