Abstract
Purpose: :
To identify the localization of indoleamine 2,3–dioxygenase (IDO) in human corneal cells and to evaluate its functional ability as a local immunosuppressive factor.
Methods: :
The expression profile of IDO was identified by RT–PCR and Western blotting in a primary culture of human corneal cells (fibroblasts, epithelial cells and endothelial cells). The IDO expression on human corneal layer was also investigated by immunofluorescence. In order to investigate the immunosuppressive function of IDO, human corneal cells were cocultured with immune cells and proliferation and apoptosis rates of immune cells were identified.
Results: :
Among the three different types of human corneal cells, mRNA and protein expression of IDO was observed in human corneal fibroblasts, and stromal layer showed higher expression of IDO. Immune cells cocultured with human corneal fibroblasts showed cell death and unique evidence of apoptosis. Moreover, treatment with a synergistic enhancer of IDO in human corneal fibroblasts increased apoptosis of cocultured immune cells.
Conclusions: :
These results suggest that human corneal fibroblasts are relatively immuno–resistant, which is consistent with the rarity of stromal rejection in clinical corneal grafting.
Keywords: cornea: basic science