The above findings indicate that the CD8 T cells from TriVax boosted mice are more susceptible to PD-1 inhibition than T cells from BiVax/IL2Cx vaccinated mice, which would explain their reduced ability to induce diabetes assuming that PD-1 checkpoint inhibition is present in the pancreas of the vaccinated RIP-gp mice. This evidence concerns the gene PDCD1 and diabetes mellitus.