Abstract
Purpose: :
The early immunological consequences of transplantation into the subretinal space have not been explored in a systematic manner. By utilizing a murine extended life RPE cell line (RPET) derived from C57BL/6 mice we were able to set up syngeneic retinal transplants in C57BL/6 hosts and allogeneic retinal transplants using sv129 mice as hosts. The RPET cell line was derived from a mouse harboring temperature sensitive simian virus 40 T-antigen (SV40T) and as such donor cells can be identified by a commercial SV40T antibody (Santa Cruz).
Methods: :
RPET cell lines were grown in DMEM with 1% fetal calf serum at 330C and transplanted as a suspension in serum free DMEM at a concentration of 105 cells/ µl.Equal numbers of grafted, sham and untreated control eyes (n=4; n=4; n=4 respectively at each time point) were used. Eyes were harvested at 1, 3, 7 & 28 days and frozen for immunocytochemistry. Sections were cut and stained for the following antibodies:- macrophage markers CD11b and F4/80; natural killer cells CD49b; SV40T to detect donor cells.
Results: :
Donor cells were clearly detectable in both syngeneic and allogeneic transplants. The numbers of SV40T positive cells seen in the transplant site were far less than those introduced. Macrophages were identified infiltrating into the transplant sites from day one post transplantation. There were no significant differences in the numbers of inflammatory cells recruited to the transplant sites between syngeneic and allogeneic hosts.
Conclusions: :
As graft cell loss and inflammatory cell recruitment were similar in both conditions we suggest that cell preparation itself or the innate immune system were responsible for the destruction and removal of the majority of transplanted cells in the early post transplant phase.
Keywords: retinal pigment epithelium • immune tolerance/privilege • transplantation