CELLULAR-ORGANIZATION IN RETINAL TRANSPLANTS USING CELL-SUSPENSIONS OR FRAGMENTS OF EMBRYONIC RETINAL TISSUE

We have investigated the cellular organization in two different types of retinal transplants using cell type-specific monoclonal antibodies. Both fragments and cell suspensions of E17-E19 Sprague-Dawley rat ret ina were transplanted to a subretinal site in congenic adult rat hosts . After a survival time of 28 days, the transplants were stained by im munocytochemistry with antibodies against rhodopsin, which stained rod s; with antibodies against HPC-1, which stained amacrine cells and out er and inner plexiform layers; and with antibodies against vimentin, w hich stained Muller cell fibers and horizontal cells. In the host reti na, the distribution of immunocytochemical staining was similar, irres pective of transplantation technique. In the transplants, the antirhod opsin staining showed that fragment transplants developed photorecepto rs in rosettes, whereas in cell suspension transplants, this staining showed a scattered distribution of photoreceptors. The HPC-1 staining showed that regions corresponding to the inner nuclear layer surrounde d both types of transplants and made large invaginations into them. In one case, using the cell suspension technique, fibres were found to r un from the inner plexiform layer of the transplant to the outer plexi form layer of the host. The vimentin staining revealed a disorganized array of Muller cell fibres in both types of transplants, but with som e concentration to the regions corresponding to the inner plexiform la yer.