Allogeneic Sensitization and Tolerance Induction After Corneal Endothelial Cell Transplantation in Mice.

PURPOSE We evaluated the allogeneic response after corneal endothelial cell transplantation in the anterior chamber (AC) in a new mouse model by examining the acquisition of a delayed-type hypersensitivity (DTH) response, induction of allogeneic AC-associated immune deviation (ACAID), and acquisition of delayed transplantation tolerance. METHOD The corneal eyecups from C57BL/6 mice were prepared. The epithelial layer was detached with EDTA solution and treated with trypsin to release mouse-derived primary corneal endothelial cells (mpCECs). The mpCECs (1 × 104 cells) were transplanted into the AC of the eye or subcutaneously (SC) into the neck of BALB/c mice. In the mouse model of endothelial cell transplantation, the endothelial cells in a 2-mm central area of the cornea were eliminated by cryoinjury. The mpCEC transplant model was evaluated by measuring allogeneic cell survival and corneal thickness. The allospecific DTH response and ACAID induction were evaluated 1 week after transplantation. The long-term transplantation tolerance was evaluated by observing a secondary penetrating keratoplasty (PKP) performed on the same donor C57BL/6 mice. RESULTS The SC injection of mpCECs induced a DTH response, whereas the AC injection induced ACAID. However, eyes inflamed by cryoinjury showed neither the DTH response nor ACAID following AC injection. The mpCECs survived for at least 1 week after injection. Penetrating keratoplasty allografts at 8 weeks after mpCEC transplantation survived indefinitely (100%). CONCLUSIONS The mpCECs display low allogenicity in the AC and are capable of inducing allogeneic tolerance. Corneal endothelial cell transplantation into the AC may represent a safe technique for allogeneic transplantation.