Suppression of graft rejection in rat keratoepithelioplasty by anterior chamber inoculation of donor lymphocytes.

A newly developed model of keratoepithelioplasty (KEP) in the rat was used to analyze the effect of anterior chamber-associated immune deviation on the suppression of corneal allograft rejection. The right eyes of Fisher rats received an anterior chamber (AC) injection of lymphocyte suspension from Dark Agouti (DA) rats (DAL group) or phosphate-buffered saline (positive control group). Seven days later, DA corneal lenticules were grafted onto both eyes of the recipients. Delayed type hypersensitivity (DTH) was also assessed in another group of Fisher rats receiving an AC injection of DA lymphocytes in the right eye. Within 15 days, 88% of the eyes in the positive control group demonstrated vigorous epithelial edema, a large area of epithelial defect, and vascularization. By contrast, in the DAL group, only 37% of the eyes showed slight epithelial edema, a small area of epithelial defect, and rare vascularization; suppression of graft rejection was observed in both eyes. DTH assay demonstrated significant suppression in the recipients of the AC injection of donor-type lymphocytes. This study indicates that the AC injection of donor-type lymphocytes prior to corneal grafting suppresses allograft rejection in the rat KEP model, correlative with the suppression of DTH reaction.