The ultrastructure of transplanted rabbit retinal epithelium.

Retinal epithelial cells from pigmented rabbits have been cultured and radiolabelled during division with 3H-thymidine and transplanted to the subretinal space of albino rabbits using a pars plana transvitreal approach. The host rabbits were maintained on cyclosporine immunosuppression after transplantation surgery. The transplant cells survive and maintain a morphologically normal appearance for at least 5 months. The pigmented epithelial cells retain their pigmentation and become integrated with the host retinal epithelium forming junctional complexes with both the host and other transplant cells. The transplant cells contact host photoreceptors with their apical processes and phagocytize outer segments. There appears to be no significant cell division among the transplant cells.