Role of recipient epithelium in promoting survival of orthotopic corneal allografts in mice.
OBJECTIVE
To determine whether epithelium-deprived corneal allografts covered with syngeneic epithelium display immune privilege in orthotopic transplantation and whether syngeneic epithelium containing antigen-presenting cells nullifies this effect.


METHODS
Epithelium-deprived allogeneic corneas (C57BL/6) and epithelium-deprived allogeneic corneas reconstituted with syngeneic (BALB/c) epithelium (containing or deprived of Langerhans' cells) were transplanted orthotopically into normal eyes of BALB/c mice. Graft survival was assessed clinically and evaluated histologically.


RESULTS
Epithelium-deprived corneal grafts survived in syngeneic recipients but were swiftly rejected in allogeneic recipients. These allografts incited intense stromal inflammation and neovascularization. Epithelium-deprived allografts that were resurfaced in vivo by syngeneic epithelium derived from immune-incompetent SCID mice also underwent intense acute rejection when placed in normal eyes of BALB/c mice. The epithelium of in vivo resurfaced grafts was replete with Langerhans' cells. By contrast, most of the epithelium-deprived allografts reconstituted in vitro with fresh, normal BALB/c corneal epithelium survived indefinitely when placed in eyes of BALB/c mice. Similar grafts reconstituted with BALB/c epithelium containing Langerhans' cells were swiftly rejected.


CONCLUSIONS
Replacement of donor epithelium with Langerhans' cell-deficient syngeneic epithelium protects orthotopic allogeneic cornea grafts (stroma plus endothelium) from immune-mediated rejection. The presence of an intact, histocompatible layer of corneal epithelium has two important effects on orthotopic corneal allografts: It suppresses nonspecific inflammation and neovascularization within the graft, and it blunts the alloimmunogenicity of the histoincompatible stroma and endothelium.
Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA.
J
J
Hori
J W
JW
Streilein
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D001854:Bone Marrow Cells / Q000502:physiology; D019573:Epithelium, Corneal / Q000502:physiology*; D016650:Fluorescein-5-isothiocyanate; D006084:Graft Rejection / Q000473:pathology; D006085:Graft Survival / Q000502:physiology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D015948:Keratoplasty, Penetrating / Q000502:physiology*; D007801:Langerhans Cells / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016513:Mice, SCID; D014184:Transplantation, Homologous
D000949:Histocompatibility Antigens Class II; D016650:Fluorescein-5-isothiocyanate