The immunopeptidomes of two transmissible cancers and their host have a common, dominant peptide motif

Transmissible cancers are malignant cells that can spread between individuals of a population, akin to both parasite and mobile graft. The survival the Tasmanian devil, largest remaining marsupial carnivore, is threatened by remarkable emergence two independent lineages transmissible cancer, devil facial tumour (DFT) 1 2 (DFT2). To aid development vaccine interrogate how histocompatibility barriers be overcome, we analysed peptides bound major complex class I (MHC-I) molecules from representative cell lines each cancer. Here, show DFT1 + IFN-γ DFT2 express restricted repertoire MHC-I allotypes compared with fibroblast cells, potentially reducing breadth peptide presentation. Comparison peptidomes IFNγ, host demonstrates dominant motif, despite differences in lines, preference for hydrophobic leucine residue at position 3 Ω peptides. present derived neural proteins, which reflects shared cellular origin could exploited design. These results suggest polymorphisms tumours ‘hidden’ common providing potential permissive passage infectious demonstrating complexity mammalian barriers.