A model for xenogenic immune response

Purpose: To develop a model for analyzing the immune response after xenogen ic human fetal retinal pigment epithtelium (HFRPE) transplantation. Materia ls ann methods: Purl sheets of HFRPE cells were isolated and attached to po ly (DL-lactide-co-glycolide) polymer films and HFRPE spheroids were formed. The spheroids were transplanted into the subretinal space of New Zealand a lbino rabbits and were observed for 5 months. Bare polymer films were trans planted into the subretinal space of Dutch Belted pigmented rabbits, servin g as control. Results: The polymer film was bioegraded within 3 weeks in th e subretinal space. No signs of inflammation in the retina or choroid were observed. The WI;RPE spheroids were easily transplanted into the subretinal space. The immune response was followed with ophthalmoscopy. Light microsc opy indicated a localized immune response in the transplanted area in which the retina and the choroid were infiltrated with immune cells. This infilt ration was denser in the choroid. Conclusions: HFRPE spheroid transplantati on may be utilized as a model for studying the xenogenic immune response af ter HFRPE transplantation. This model may also have applications in evaluat ing the role of immune suppressive agents in preventing rejection after HFR PE transplantation.