Fig 7. Schematic illustration of the possible mechanism for IDO fibroblast therapy model.

IDO-expressing fibroblasts are injected to recently diabetic mice, intraperitoneally. A group of these fibroblasts express CCR7 and migrate to regional lymph nodes. These fibroblasts get in touch with naive T cells there and via IDO and PD-L1/2 medicated mechanisms convert them into regulatory T cells. These Tregs will then reach pancreas through blood and lymphatic streams and suppress autoimmune and inflammatory effectors immune cells. As a result, insulitis level diminishes and consequently diabetes is controlled.