Antigenicity of porcine cornea as xenograft

Purpose. To investigate the antigenicity of porcine corneal stroma. as xenograft to man. Methods. The localization of alpha-gal epitope in the porcine eye was determined using biotinylated Griffonia simplicifolia I isolectin B4. Porcine corneal stromal was inserted into corneal stromal pockets of cynomolgus monkeys. Immunohistochemistry was performed to analyze the immunological reaction in the monkey. Results. Immunohistochemistry showed no alpha-gal epitope in the porcine cornea except for several keratocytes in the anterior-most part. Haze and keratic precipitates developed in two corneas out of three corneas that were followed up until 6 months after the surgery. In these two corneas, infiltrating cells included CD4(+), CD8(+), or HAM56(+) cells, suggesting that haze and keratic precipitates were induced by cellular rejection to porcine corneal stroma. Conclusions. Porcine corneal stroma induces no hyperacute rejection but mild cellular rejection when transplanted in the cornea of cynomolgus monkeys.